From 6cae939e4adc0f0b74331253d50a1dac4b6d9e89 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Axel=20M=C3=BCller?=
 <87638982+molshape@users.noreply.github.com>
Date: Sat, 2 Aug 2025 12:25:10 +0200
Subject: [PATCH 1/2] Update Atomic Weights

- Update atomic weights for F, Ar, Sc, Y, Zr, Gd, Ho, Tm, and Lu in `elements.py`
- Update `README.md` accordingly
- Update literature references
---
 README.md                         |   4 +-
 misc/{AtWt19.html => AtWt23.html} | 104 +++++++++++++++---------------
 src/chemformula/elements.py       |  24 +++----
 3 files changed, 68 insertions(+), 64 deletions(-)
 rename misc/{AtWt19.html => AtWt23.html} (83%)
diff --git a/README.md b/README.md
index dbec55d..8ab084c 100644
--- a/README.md
+++ b/README.md
@@ -273,7 +273,9 @@ All atomic weights are taken from the IUPAC Commission on Isotopic Abundances an
 - [*Pure Appl. Chem.*, **2016**, *88*, 1225-1229](https://doi.org/10.1515/pac-2016-0501)
 - [*Chem. Int.*, **2018**, *40*(4), 23-24](https://doi.org/10.1515/ci-2018-0409)
 - [*Chem. Int.*, **2020**, *42*(2), 31](https://doi.org/10.1515/ci-2020-0222)
+- [*Pure Appl. Chem.*, **2022**, *94*(5), 573-600](https://doi.org/10.1515/pac-2019-0603)
+- [*Chem. Int.*, **2025**, *47*(1), 20-20](https://doi.org/10.1515/ci-2025-0105)
 
-The actual data has been downloaded from https://www.qmul.ac.uk/sbcs/iupac/AtWt/ as of August 8th, 2021. The original data has been mirrored to [/misc/AtWt19.html](https://github.com/molshape/ChemFormula/blob/main/misc/AtWt19.html).
+The current data has been downloaded from https://iupac.qmul.ac.uk/AtWt/ as of August 2<sup>nd</sup>, 2025. The original data has been mirrored to [/misc/AtWt23.html](https://github.com/molshape/ChemFormula/blob/main/misc/AtWt23.html).
 
 Quoted atomic weights are those suggested for materials where the origin of the sample is unknown. For most radioactive elements the isotope with the longest half-life is quoted as an integer.
diff --git a/misc/AtWt19.html b/misc/AtWt23.html
similarity index 83%
rename from misc/AtWt19.html
rename to misc/AtWt23.html
index bd2ad10..0a85c0b 100644
--- a/misc/AtWt19.html
+++ b/misc/AtWt23.html
@@ -1,5 +1,5 @@
-<html><head><title>2019 Atomic Weights</title>
-<base href="https://www.qmul.ac.uk/sbcs/iupac/AtWt/index.html">
+<html><head><title>2023 Atomic Weights</title>
+<base href="https://iupac.qmul.ac.uk/AtWt/index.html">
 <meta name="keywords" content="IUPAC atomic weight relative atomic mass">
 <meta name="description" content="The full text of the IUPAC table of atomic weights">
 <meta name="object type" content="document">
@@ -7,15 +7,15 @@
 
 <center><b><a href="http://www.ciaaw.org">IUPAC Commission on Isotopic Abundances and Atomic Weights</a>.</b><p>
 
-<h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
+<h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2023</b></h1><p>
 
-These tables are based on the <a href="AtWt15.html">2015 table</a> with changes from the 2015 table for the values of aluminium, argon, cobalt, gold, holmium, iridium, manganese, niobium, praseodymium, protactinium, rhodium, terbium, thulium and yttrium. See <a href="http://iupac.org/standard-atomic-weights-of-14-chemical-elements-revised/">report 5 June 2018</a>. The revised value of hafnium was reported <a href="https://iupac.org/standard-atomic-weight-of-hafnium-revised/">11 December 2019</a><p>
+These tables are based on the <a href="https://doi.org/10.1515/pac-2019-0603">2021 table</a> with changes from the 2019 table for the values of Ar, Hf, Ir, Pb and Yb and changes to the uncertainty for Al, Au, Co, F, Ho, Mn, Nb, Pa, Pr, Rh, Sc, Tb, Tm, and Y. The values of<a href="https://iupac.org/standard-atomic-weights-of-three-technology-critical-elements-revised/"> Gd, Lu and Zr were revised and published in 2024</a>.<p>
 
-<span style="color: #ff000"><b>https://www.qmul.ac.uk/sbcs/iupac/AtWt/ </b></span></center><p>
+<span style="color: #ff000"><b>https://iupac.qmul.ac.uk/AtWt/ </b></span></center><p>
 
 World Wide Web version of atomic weight data originally prepared by <a href="mailto:g.p.moss@qmul.ac.uk">G. P. Moss</a>, from a file provided by D. R. Lide.<p>
 
-Previous values may be consulted from the <a href = "AtWt93.html">1993 table</a>, the <a href = "AtWt95.html">1995 table</a>, the <a href = "AtWt97.html">1997 table</a>, the <a href = "AtWt99.html">1999 table</a>, the <a href = "AtWt01.html">2001 table</a>, the <a href = "AtWt05.html">2005 table</a>, the <a href = "AtWt07.html">2007 table</a>, the <a href = "AtWt09.html">2009 table</a>, the <a href = "AtWt11.html">2011 table</a>, the  <a href = "AtWt13.html">2013 table</a> or the <a href = "AtWt15.html">2015 table</a>.<p>
+Previous values may be consulted from the <a href = "AtWt93.html">1993 table</a>, the <a href = "AtWt95.html">1995 table</a>, the <a href = "AtWt97.html">1997 table</a>, the <a href = "AtWt99.html">1999 table</a>, the <a href = "AtWt01.html">2001 table</a>, the <a href = "AtWt05.html">2005 table</a>, the <a href = "AtWt07.html">2007 table</a>, the <a href = "AtWt09.html">2009 table</a>, the <a href = "AtWt11.html">2011 table</a>, the  <a href = "AtWt13.html">2013 table</a>, the <a href = "AtWt15.html">2015 table</a>, <a href = "AtWt19.html">2019 table or the <a href = "AtWt21.html">2021 table</a>.<p>
 
 The standard atomic weights of twelve elements having two or more stable isotopes have  variability of atomic-weight values in natural terrestrial materials. These are given in <a href="#01">table 1</a> below. In the other lists the values quoted are those suggested for material where the origin of the sample is unknown. For radioactive elements the isotope with the longest half-life is quoted in parenthesis. The original paper should be consulted for full details of the variation in atomic weight and the half life of the radioisotopes quoted below. <p>
 
@@ -45,34 +45,34 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>82</td><td>Pb</td><td>lead</td><td>206.14</td><td>207.94</td></tr>
 </table></center><p>
 
-See original paper for the range of these elements from different sources [Isotope-abundance variations and atomic weights of selected elements: 2016 (IUPAC Technical Report), <a href="https://www.degruyter.com/view/j/pac.2016.88.issue-12/pac-2016-0302/pac-2016-0302.xml"><i>Pure Appl. Chem.</i> 2016, <b>88</b>(12), 1203-1224.</a> and <a href="https://www.degruyter.com/document/doi/10.1515/pac-2018-0916/html"> <i>Pure Appl. Chem.</i> 2021, <b>93</b>(1), 155-166</a>]<p>
+See original paper for the range of these elements from different sources [Isotope-abundance variations and atomic weights of selected elements: 2016 (IUPAC Technical Report), <a href="https://www.degruyter.com/view/j/pac.2016.88.issue-12/pac-2016-0302/pac-2016-0302.xml"><i>Pure Appl. Chem.</i> 2016, <b>88</b>(12), 1203-1224.</a>, <a href="https://www.degruyter.com/document/doi/10.1515/pac-2018-0916/html"> <i>Pure Appl. Chem.</i> 2021, <b>93</b>(1), 155-166</a> and <a href=" https://doi.org/10.1515/pac-2019-0603"><i>Pure Appl. Chem.</i> 2022, <b>94</b></a>]<p>
 
 
 <center><a name="02"><h3><b>Table 2. List of Elements in Atomic Number Order.</b></h3></a><p>
  
 <table border=0 cellspace=13 cellpadding=0>
 <tr><td>At No &nbsp; &nbsp; </td><td>Symbol &nbsp; &nbsp; </td><td>Name</td><td>Atomic Wt</td><td>Notes</td></tr>
-<tr><td>1</td><td>H</td><td>Hydrogen</td><td>1.008</td><td>3, 5</td></tr>
+<tr><td>1</td><td>H</td><td>Hydrogen</td><td>1.0080(2)</td><td>3, 5</td></tr>
 <tr><td>2</td><td>He</td><td>Helium</td><td>4.002 602(2)</td><td>1, 2</td></tr>
-<tr><td>3</td><td>Li</td><td>Lithium</td><td>6.94</td><td>3, 5</td></tr>
+<tr><td>3</td><td>Li</td><td>Lithium</td><td>6.94(6)</td><td>3, 5</td></tr>
 <tr><td>4</td><td>Be</td><td>Beryllium</td><td>9.012 1831(5)</td></tr>
-<tr><td>5</td><td>B</td><td>Boron</td><td>10.81</td><td>3, 5</td></tr>
-<tr><td>6</td><td>C</td><td>Carbon</td><td>12.011</td><td>5</td></tr>
-<tr><td>7</td><td>N</td><td>Nitrogen</td><td>14.007</td><td>5</td></tr>
-<tr><td>8</td><td>O</td><td>Oxygen</td><td>15.999</td><td>5</td></tr>
-<tr><td>9</td><td>F</td><td>Fluorine</td><td>18.998 403 163(6)</td></tr>
+<tr><td>5</td><td>B</td><td>Boron</td><td>10.81(2)</td><td>3, 5</td></tr>
+<tr><td>6</td><td>C</td><td>Carbon</td><td>12.011(2)</td><td>5</td></tr>
+<tr><td>7</td><td>N</td><td>Nitrogen</td><td>14.007(1)</td><td>5</td></tr>
+<tr><td>8</td><td>O</td><td>Oxygen</td><td>15.999(1)</td><td>5</td></tr>
+<tr><td>9</td><td>F</td><td>Fluorine</td><td>18.998 403 162(5)</td></tr>
 <tr><td>10</td><td>Ne</td><td>Neon</td><td>20.1797(6)</td><td>1, 3</td></tr>
 <tr><td>11</td><td>Na</td><td>Sodium</td><td>22.989 769 28(2) &nbsp; &nbsp; </td></tr>
-<tr><td>12</td><td>Mg</td><td>Magnesium</td><td>24.305</td><td>5</td></tr>
+<tr><td>12</td><td>Mg</td><td>Magnesium</td><td>24.305(2)</td><td>5</td></tr>
 <tr><td>13</td><td>Al</td><td>Aluminium</td><td>26.981 5384(3)</td></tr>
-<tr><td>14</td><td>Si</td><td>Silicon</td><td>28.085</td><td>5</td></tr>
-<tr><td>15</td><td>P</td><td>Phosphorus</td><td>30.973 761 998(5)</td></tr>
-<tr><td>16</td><td>S</td><td>Sulfur</td><td>32.06</td><td>5</td></tr>
-<tr><td>17</td><td>Cl</td><td>Chlorine</td><td>35.45</td><td>3, 5</td></tr>
-<tr><td>18</td><td>Ar</td><td>Argon</td><td>39.948(1)</td><td>1, 2, 5</td></tr>
+<tr><td>14</td><td>Si</td><td>Silicon</td><td>28.085(1)</td><td>5</td></tr>
+<tr><td>15</td><td>P</td><td>Phosphorus</td><td>(30.973 761 998(5)</td></tr>
+<tr><td>16</td><td>S</td><td>Sulfur</td><td>32.06(2)</td><td>5</td></tr>
+<tr><td>17</td><td>Cl</td><td>Chlorine</td><td>35.45(1)</td><td>3, 5</td></tr>
+<tr><td>18</td><td>Ar</td><td>Argon</td><td>39.95(16)</td><td>1, 2, 5</td></tr>
 <tr><td>19</td><td>K</td><td>Potassium</td><td>39.0983(1)</td><td></td></tr>
 <tr><td>20</td><td>Ca</td><td>Calcium</td><td>40.078(4)</td><td></td></tr>
-<tr><td>21</td><td>Sc</td><td>Scandium</td><td>44.955 908(5)</td></tr>
+<tr><td>21</td><td>Sc</td><td>Scandium</td><td>44.955 907(4)</td></tr>
 <tr><td>22</td><td>Ti</td><td>Titanium</td><td>47.867(1)</td></tr>
 <tr><td>23</td><td>V</td><td>Vanadium</td><td>50.9415(1)</td></tr>
 <tr><td>24</td><td>Cr</td><td>Chromium</td><td>51.9961(6)</td></tr>
@@ -86,12 +86,12 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>32</td><td>Ge</td><td>Germanium</td><td>72.630(8)</td></tr>
 <tr><td>33</td><td>As</td><td>Arsenic</td><td>74.921 595(6)</td></tr>
 <tr><td>34</td><td>Se</td><td>Selenium</td><td>78.971(8)</td></tr>
-<tr><td>35</td><td>Br</td><td>Bromine</td><td>79.904</td><td>5</td></tr>
+<tr><td>35</td><td>Br</td><td>Bromine</td><td>79.904(3)_</td><td>5</td></tr>
 <tr><td>36</td><td>Kr</td><td>Krypton</td><td>83.798(2)</td><td>1, 3</td></tr>
 <tr><td>37</td><td>Rb</td><td>Rubidium</td><td>85.4678(3)</td><td>1</td></tr>
 <tr><td>38</td><td>Sr</td><td>Strontium</td><td>87.62(1)</td><td>1, 2</td></tr>
-<tr><td>39</td><td>Y</td><td>Yttrium</td><td>88.905 84(1)</td></tr>
-<tr><td>40</td><td>Zr</td><td>Zirconium</td><td>91.224(2)</td><td>1</td></tr>
+<tr><td>39</td><td>Y</td><td>Yttrium</td><td>88.905 838(2)</td></tr>
+<tr><td>40</td><td>Zr</td><td>Zirconium</td><td>91.222(3)</td><td>1</td></tr>
 <tr><td>41</td><td>Nb</td><td>Niobium</td><td>92.906 37(1)</td></tr>
 <tr><td>42</td><td>Mo</td><td>Molybdenum</td><td>95.95(1)</td><td>1</td></tr>
 <tr><td>43</td><td>Tc</td><td>Technetium</td><td>[97]</td><td>4</td></tr>
@@ -115,14 +115,14 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>61</td><td>Pm</td><td>Promethium</td><td>[145]</td><td></td></tr>
 <tr><td>62</td><td>Sm</td><td>Samarium</td><td>150.36(2)</td><td>1</td></tr>
 <tr><td>63</td><td>Eu</td><td>Europium</td><td>151.964(1)</td><td>1</td></tr>
-<tr><td>64</td><td>Gd</td><td>Gadolinium</td><td>157.25(3)</td><td>1</td></tr>
-<tr><td>65</td><td>Tb</td><td>Terbium</td><td>158.925 354(8)</td></tr>
+<tr><td>64</td><td>Gd</td><td>Gadolinium</td><td>157.249(2)</td><td>1</td></tr>
+<tr><td>65</td><td>Tb</td><td>Terbium</td><td>158.925 354(7)</td></tr>
 <tr><td>66</td><td>Dy</td><td>Dysprosium</td><td>162.500(1)</td><td>1</td></tr>
-<tr><td>67</td><td>Ho</td><td>Holmium</td><td>164.930 328(7)</td></tr>
+<tr><td>67</td><td>Ho</td><td>Holmium</td><td>164.930 329(5)</td></tr>
 <tr><td>68</td><td>Er</td><td>Erbium</td><td>167.259(3)</td><td>1</td></tr>
-<tr><td>69</td><td>Tm</td><td>Thulium</td><td>168.934 218(6)</td></tr>
+<tr><td>69</td><td>Tm</td><td>Thulium</td><td>168.934 219(5)</td></tr>
 <tr><td>70</td><td>Yb</td><td>Ytterbium</td><td>173.045(10)</td><td>1</td></tr>
-<tr><td>71</td><td>Lu</td><td>Lutetium</td><td>174.9668(1)</td><td>1</td></tr>
+<tr><td>71</td><td>Lu</td><td>Lutetium</td><td>174.966 69(5)</td><td>1</td></tr>
 <tr><td>72</td><td>Hf</td><td>Hafnium</td><td>178.486(6)</td></tr>
 <tr><td>73</td><td>Ta</td><td>Tantalum</td><td>180.947 88(2)</td></tr>
 <tr><td>74</td><td>W</td><td>Tungsten</td><td>183.84(1)</td></tr>
@@ -132,8 +132,8 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>78</td><td>Pt</td><td>Platinum</td><td>195.084(9)</td></tr>
 <tr><td>79</td><td>Au</td><td>Gold</td><td>196.966 570(4)</td></tr>
 <tr><td>80</td><td>Hg</td><td>Mercury</td><td>200.592(3)</td></tr>
-<tr><td>81</td><td>Tl</td><td>Thallium</td><td>204.38</td><td>5</td></tr>
-<tr><td>82</td><td>Pb</td><td>Lead</td><td>207.2(1)</td><td>1, 2, 5</td></tr>
+<tr><td>81</td><td>Tl</td><td>Thallium</td><td>204.38(1)</td><td>5</td></tr>
+<tr><td>82</td><td>Pb</td><td>Lead</td><td>207.2(1.1)</td><td>1, 2, 5</td></tr>
 <tr><td>83</td><td>Bi</td><td>Bismuth</td><td>208.980 40(1)</td></tr>
 <tr><td>84</td><td>Po</td><td>Polonium</td><td>[209]</td><td>4</td></tr>
 <tr><td>85</td><td>At</td><td>Astatine</td><td>[210]</td><td>4</td></tr>
@@ -196,7 +196,7 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>13</td><td>Al</td><td>Aluminium</td><td>26.981 5384(3)</td></tr>
 <tr><td>95</td><td>Am</td><td>Americium</td><td>[243]</td><td>4</td></tr>
 <tr><td>51</td><td>Sb</td><td>Antimony</td><td>121.760(1)</td><td>1 </td></tr>
-<tr><td>18</td><td>Ar</td><td>Argon</td><td>39.948(1)</td><td>1, 2, 5</td></tr>
+<tr><td>18</td><td>Ar</td><td>Argon</td><td>39.95(16)</td><td>1, 2, 5</td></tr>
 <tr><td>33</td><td>As</td><td>Arsenic</td><td>74.921 595(6)</td></tr>
 <tr><td>85</td><td>At</td><td>Astatine</td><td>[210]</td><td>4</td></tr>
 <tr><td>56</td><td>Ba</td><td>Barium</td><td>137.327(7)</td></tr>
@@ -204,13 +204,13 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>4</td><td>Be</td><td>Beryllium</td><td>9.012 1831(5)</td></tr>
 <tr><td>83</td><td>Bi</td><td>Bismuth</td><td>208.980 40(1)</td></tr>
 <tr><td>107</td><td>Bh</td><td>Bohrium</td><td>[270]</td><td>4</td></tr>
-<tr><td>5</td><td>B</td><td>Boron</td><td>10.81</td><td>3, 5</td></tr>
-<tr><td>35</td><td>Br</td><td>Bromine</td><td>79.904</td><td>5</td></tr>
+<tr><td>5</td><td>B</td><td>Boron</td><td>10.81(2)</td><td>3, 5</td></tr>
+<tr><td>35</td><td>Br</td><td>Bromine</td><td>79.904(3)</td><td>5</td></tr>
 <tr><td>48</td><td>Cd</td><td>Cadmium</td><td>112.414(4)</td><td>1 </td></tr>
 <tr><td>55</td><td>Cs</td><td>Caesium</td><td>132.905 451 96(6)</td></tr>
 <tr><td>20</td><td>Ca</td><td>Calcium</td><td>40.078(4)</td><td>1</td></tr>
 <tr><td>98</td><td>Cf</td><td>Californium</td><td>[251]</td><td>4</td></tr>
-<tr><td>6</td><td>C</td><td>Carbon</td><td>12.011</td><td>5</td></tr>
+<tr><td>6</td><td>C</td><td>Carbon</td><td>12.011(2)</td><td>5</td></tr>
 <tr><td>58</td><td>Ce</td><td>Cerium</td><td>140.116(1)</td><td>1</td></tr>
 <tr><td>17</td><td>Cl</td><td>Chlorine</td><td>35.45</td><td>3, 5</td></tr>
 <tr><td>24</td><td>Cr</td><td>Chromium</td><td>51.9961(6)</td></tr>
@@ -226,16 +226,16 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>63</td><td>Eu</td><td>Europium</td><td>151.964(1)</td><td>1</td></tr>
 <tr><td>100</td><td>Fm</td><td>Fermium</td><td>[257]</td><td>4</td></tr>
 <tr><td>114</td><td>Fl</td><td>Flerovium</td><td>[289]</td><td>4</td></tr>
-<tr><td>9</td><td>F</td><td>Fluorine</td><td>18.998 403 163(6)</td></tr>
+<tr><td>9</td><td>F</td><td>Fluorine</td><td>18.998 403 162(5)</td></tr>
 <tr><td>87</td><td>Fr</td><td>Francium</td><td>[223]</td><td>4</td></tr>
-<tr><td>64</td><td>Gd</td><td>Gadolinium</td><td>157.25(3)</td><td>1</td></tr>
+<tr><td>64</td><td>Gd</td><td>Gadolinium</td><td>157.249(2)</td><td>1</td></tr>
 <tr><td>31</td><td>Ga</td><td>Gallium</td><td>69.723(1)</td></tr>
 <tr><td>32</td><td>Ge</td><td>Germanium</td><td>72.630(8)</td></tr>
 <tr><td>79</td><td>Au</td><td>Gold</td><td>196.966 570(4)</td></tr>
 <tr><td>72</td><td>Hf</td><td>Hafnium</td><td>178.486(6)</td></tr>
 <tr><td>108</td><td>Hs</td><td>Hassium</td><td>[270]</td><td>4</td></tr>
 <tr><td>2</td><td>He</td><td>Helium</td><td>4.002 602(2)</td><td>1, 2</td></tr>
-<tr><td>67</td><td>Ho</td><td>Holmium</td><td>164.930 328(7)</td></tr>
+<tr><td>67</td><td>Ho</td><td>Holmium</td><td>164.930 329(5)</td></tr>
 <tr><td>1</td><td>H</td><td>Hydrogen</td><td>1.008</td><td>3, 5</td></tr>
 <tr><td>49</td><td>In</td><td>Indium</td><td>114.818(1)</td></tr>
 <tr><td>53</td><td>I</td><td>Iodine</td><td>126.904 47(3)</td></tr>
@@ -244,11 +244,11 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>36</td><td>Kr</td><td>Krypton</td><td>83.798(2)</td><td>1, 3</td></tr>
 <tr><td>57</td><td>La</td><td>Lanthanum</td><td>138.905 47(7)</td><td>1</td></tr>
 <tr><td>103</td><td>Lr</td><td>Lawrencium</td><td>[262]</td><td>4</td></tr>
-<tr><td>82</td><td>Pb</td><td>Lead</td><td>207.2(1)</td><td>1, 2, 5</td></tr>
+<tr><td>82</td><td>Pb</td><td>Lead</td><td>207.2(1.1)</td><td>1, 2, 5</td></tr>
 <tr><td>3</td><td>Li</td><td>Lithium</td><td>6.94</td><td>3, 5</td></tr>
 <tr><td>116</td><td>Lv</td><td>Livermorium</td><td>[293]</td><td>4</td></tr>
-<tr><td>71</td><td>Lu</td><td>Lutetium</td><td>174.9668(1)</td><td>1</td></tr>
-<tr><td>12</td><td>Mg</td><td>Magnesium</td><td>24.305</td><td>5</td></tr>
+<tr><td>71</td><td>Lu</td><td>Lutetium</td><td>174.966 69(5)</td><td>1</td></tr>
+<tr><td>12</td><td>Mg</td><td>Magnesium</td><td>24.305(2)</td><td>5</td></tr>
 <tr><td>25</td><td>Mn</td><td>Manganese</td><td>54.938 043(2)</td></tr>
 <tr><td>109</td><td>Mt</td><td>Meitnerium</td><td>[278]</td><td>4</td></tr>
 <tr><td>101</td><td>Md</td><td>Mendelevium</td><td>[258]</td><td>4</td></tr>
@@ -261,11 +261,11 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>28</td><td>Ni</td><td>Nickel</td><td>58.6934(4)</td></tr>
 <tr><td>113</td><td>Nh</td><td>Nihonium </td><td>[286]</td><td>4</td></tr>
 <tr><td>41</td><td>Nb</td><td>Niobium</td><td>92.906 37(1)</td></tr>
-<tr><td>7</td><td>N</td><td>Nitrogen</td><td>14.007</td><td>5</td></tr>
+<tr><td>7</td><td>N</td><td>Nitrogen</td><td>14.007(1)</td><td>5</td></tr>
 <tr><td>102</td><td>No</td><td>Nobelium</td><td>[259]</td><td>4</td></tr>
 <tr><td>118</td><td>Og</td><td>Oganesson</td><td>[294]</td><td>4</td></tr>
 <tr><td>76</td><td>Os</td><td>Osmium</td><td>190.23(3)</td><td>1</td></tr>
-<tr><td>8</td><td>O</td><td>Oxygen</td><td>15.999</td><td>5</td></tr>
+<tr><td>8</td><td>O</td><td>Oxygen</td><td>15.999(1)</td><td>5</td></tr>
 <tr><td>46</td><td>Pd</td><td>Palladium</td><td>106.42(1)</td><td>1</td></tr>
 <tr><td>15</td><td>P</td><td>Phosphorus</td><td>30.973 761 998(5)</td></tr>
 <tr><td>78</td><td>Pt</td><td>Platinum</td><td>195.084(9)</td></tr>
@@ -284,22 +284,22 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>44</td><td>Ru</td><td>Ruthenium</td><td>101.07(2)</td><td>1</td></tr>
 <tr><td>104</td><td>Rf</td><td>Rutherfordium</td><td>[267]</td><td>4</td></tr>
 <tr><td>62</td><td>Sm</td><td>Samarium</td><td>150.36(2)</td><td>1 </td></tr>
-<tr><td>21</td><td>Sc</td><td>Scandium</td><td>44.955 908(5)</td></tr>
+<tr><td>21</td><td>Sc</td><td>Scandium</td><td>44.955 907(4)</td></tr>
 <tr><td>106</td><td>Sg</td><td>Seaborgium</td><td>[269]</td><td>4</td></tr>
 <tr><td>34</td><td>Se</td><td>Selenium</td><td>78.971(8)</td></tr>
-<tr><td>14</td><td>Si</td><td>Silicon</td><td>28.085</td><td>5</td></tr>
+<tr><td>14</td><td>Si</td><td>Silicon</td><td>28.085(1)</td><td>5</td></tr>
 <tr><td>47</td><td>Ag</td><td>Silver</td><td>107.8682(2)</td><td>1</td></tr>
 <tr><td>11</td><td>Na</td><td>Sodium</td><td>22.989 769 28(2) &nbsp; &nbsp; </td></tr>
 <tr><td>38</td><td>Sr</td><td>Strontium</td><td>87.62(1)</td><td>1, 2</td></tr>
-<tr><td>16</td><td>S</td><td>Sulfur</td><td>32.06</td><td>5</td></tr>
+<tr><td>16</td><td>S</td><td>Sulfur</td><td>32.06(2)</td><td>5</td></tr>
 <tr><td>73</td><td>Ta</td><td>Tantalum</td><td>180.947 88(2)</td></tr>
 <tr><td>43</td><td>Tc</td><td>Technetium</td><td>[97]</td><td>4</td></tr>
 <tr><td>52</td><td>Te</td><td>Tellurium</td><td>127.60(3)</td><td>1</td></tr>
 <tr><td>117</td><td>Ts</td><td>Tennessine</td><td>[293]</td><td>4</td></tr>
-<tr><td>65</td><td>Tb</td><td>Terbium</td><td>158.925 354(8)</td></tr>
-<tr><td>81</td><td>Tl</td><td>Thallium</td><td>204.38</td><td>5</td></tr>
+<tr><td>65</td><td>Tb</td><td>Terbium</td><td>158.925 354(7)</td></tr>
+<tr><td>81</td><td>Tl</td><td>Thallium</td><td>204.38(1)</td><td>5</td></tr>
 <tr><td>90</td><td>Th</td><td>Thorium</td><td>232.0377(4)</td><td>1, 4</td></tr> 
-<tr><td>69</td><td>Tm</td><td>Thulium</td><td>168.934 218(6)</td></tr>
+<tr><td>69</td><td>Tm</td><td>Thulium</td><td>168.934 219(5)</td></tr>
 <tr><td>50</td><td>Sn</td><td>Tin</td><td>118.710(7)</td><td>1</td></tr>
 <tr><td>22</td><td>Ti</td><td>Titanium</td><td>47.867(1)</td></tr>
 <tr><td>74</td><td>W</td><td>Tungsten</td><td>183.84(1)</td></tr>
@@ -307,9 +307,9 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>23</td><td>V</td><td>Vanadium</td><td>50.9415(1)</td></tr>
 <tr><td>54</td><td>Xe</td><td>Xenon</td><td>131.293(6)</td><td>1, 3</td></tr>
 <tr><td>70</td><td>Yb</td><td>Ytterbium</td><td>173.045(10)</td><td>1</td></tr>
-<tr><td>39</td><td>Y</td><td>Yttrium</td><td>88.905 84(1)</td></tr>
+<tr><td>39</td><td>Y</td><td>Yttrium</td><td>88.905 838(2)</td></tr>
 <tr><td>30</td><td>Zn</td><td>Zinc</td><td>65.38(2)</td><td>2</td></tr>
-<tr><td>40</td><td>Zr</td><td>Zirconium</td><td>91.224(2)</td><td>1</td></tr>
+<tr><td>40</td><td>Zr</td><td>Zirconium</td><td>91.222(3)</td><td>1</td></tr>
 </table></center>
 
 <ol>
@@ -318,7 +318,7 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 
 <li>Range in isotopic composition of normal terrestrial material prevents a more precise value being given; the tabulated value should be applicable to any normal material.
 
-<li>Modified isotopic compositions may be found in commercially available material because it has been subject to an undisclosed or inadvertant isotopic fractionation. Substantial deviations in atomic weight of the element from that given in the Table can occur.
+<li>Modified isotopic compositions may be found in commercially available material because it has been subject to an undisclosed or inadvertent isotopic fractionation. Substantial deviations in atomic weight of the element from that given in the Table can occur.
 
 <li>Element has no stable nuclides. The value enclosed in brackets, e.g. [209], indicates the mass number of the longest-lived isotope of the element. However three such elements (Th, Pa, and U) do have a characteristic terrestrial isotopic composition, and for these an atomic weight is tabulated.
 
diff --git a/src/chemformula/elements.py b/src/chemformula/elements.py
index d1b47d5..0e508e5 100644
--- a/src/chemformula/elements.py
+++ b/src/chemformula/elements.py
@@ -1,5 +1,5 @@
 '''
-ATOMIC WEIGHTS OF THE ELEMENTS (2019)
+ATOMIC WEIGHTS OF THE ELEMENTS (2023)
 from the IUPAC Commission on Isotopic Abundances and Atomic Weights
 
 Based on the following reports:
@@ -10,8 +10,10 @@
     - Pure Appl. Chem., 2016, 88, 1225-1229 (https://doi.org/10.1515/pac-2016-0501)
     - Chem. Int., 2018, 40(4), 23-24        (https://doi.org/10.1515/ci-2018-0409)
     - Chem. Int., 2020, 42(2), 31           (https://doi.org/10.1515/ci-2020-0222)
+    - Pure Appl. Chem., 2022, 94(5), 573-600 (https://doi.org/10.1515/pac-2019-0603)
+    - Chem. Int., 2025, 47(1), 20-20         (https://doi.org/10.1515/ci-2025-0105)
 
-Data taken from: https://www.qmul.ac.uk/sbcs/iupac/AtWt/
+Data taken from: https://iupac.qmul.ac.uk/AtWt/
 
 Quoted atomic weights are those suggested for materials where the origin of the sample is unknown.
 For radioactive elements the isotope with the longest half-life is quoted as an integer.
@@ -28,7 +30,7 @@ def atomic_weight(element):
         "C":   12.011,
         "N":   14.007,
         "O":   15.999,
-        "F":   18.998403163,
+        "F":   18.998403162,
         "Ne":  20.1797,
         "Na":  22.98976928,
         "Mg":  24.305,
@@ -37,10 +39,10 @@ def atomic_weight(element):
         "P":   30.973761998,
         "S":   32.06,
         "Cl":  35.45,
-        "Ar":  39.948,
+        "Ar":  39.95,
         "K":   39.0983,
         "Ca":  40.078,
-        "Sc":  44.955908,
+        "Sc":  44.955907,
         "Ti":  47.867,
         "V":   50.9415,
         "Cr":  51.9961,
@@ -58,8 +60,8 @@ def atomic_weight(element):
         "Kr":  83.798,
         "Rb":  85.4678,
         "Sr":  87.62,
-        "Y":   88.90584,
-        "Zr":  91.224,
+        "Y":   88.905838,
+        "Zr":  91.222,
         "Nb":  92.90637,
         "Mo":  95.95,
         "Tc":  97,
@@ -83,14 +85,14 @@ def atomic_weight(element):
         "Pm": 145,
         "Sm": 150.36,
         "Eu": 151.964,
-        "Gd": 157.25,
+        "Gd": 157.249,
         "Tb": 158.925354,
         "Dy": 162.500,
-        "Ho": 164.930328,
+        "Ho": 164.930329,
         "Er": 167.259,
-        "Tm": 168.934218,
+        "Tm": 168.934219,
         "Yb": 173.045,
-        "Lu": 174.9668,
+        "Lu": 174.96669,
         "Hf": 178.486,
         "Ta": 180.94788,
         "W":  183.84,

From 9b9b6ab561009d7274f1e06f27fe726a40f098e5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Axel=20M=C3=BCller?=
 <87638982+molshape@users.noreply.github.com>
Date: Sat, 2 Aug 2025 12:25:10 +0200
Subject: [PATCH 2/2] Update Atomic Weights -> 1.4.0

- Update atomic weights for F, Ar, Sc, Y, Zr, Gd, Ho, Tm, and Lu in `elements.py`
- Update `README.md` accordingly
- Update literature references
- Bump version to 1.4.0
---
 README.md                         |   4 +-
 misc/{AtWt19.html => AtWt23.html} | 104 +++++++++++++++---------------
 pyproject.toml                    |   2 +-
 src/chemformula/elements.py       |  24 +++----
 uv.lock                           |   2 +-
 5 files changed, 70 insertions(+), 66 deletions(-)
 rename misc/{AtWt19.html => AtWt23.html} (83%)

diff --git a/README.md b/README.md
index dbec55d..8ab084c 100644
--- a/README.md
+++ b/README.md
@@ -273,7 +273,9 @@ All atomic weights are taken from the IUPAC Commission on Isotopic Abundances an
 - [*Pure Appl. Chem.*, **2016**, *88*, 1225-1229](https://doi.org/10.1515/pac-2016-0501)
 - [*Chem. Int.*, **2018**, *40*(4), 23-24](https://doi.org/10.1515/ci-2018-0409)
 - [*Chem. Int.*, **2020**, *42*(2), 31](https://doi.org/10.1515/ci-2020-0222)
+- [*Pure Appl. Chem.*, **2022**, *94*(5), 573-600](https://doi.org/10.1515/pac-2019-0603)
+- [*Chem. Int.*, **2025**, *47*(1), 20-20](https://doi.org/10.1515/ci-2025-0105)
 
-The actual data has been downloaded from https://www.qmul.ac.uk/sbcs/iupac/AtWt/ as of August 8th, 2021. The original data has been mirrored to [/misc/AtWt19.html](https://github.com/molshape/ChemFormula/blob/main/misc/AtWt19.html).
+The current data has been downloaded from https://iupac.qmul.ac.uk/AtWt/ as of August 2<sup>nd</sup>, 2025. The original data has been mirrored to [/misc/AtWt23.html](https://github.com/molshape/ChemFormula/blob/main/misc/AtWt23.html).
 
 Quoted atomic weights are those suggested for materials where the origin of the sample is unknown. For most radioactive elements the isotope with the longest half-life is quoted as an integer.
diff --git a/misc/AtWt19.html b/misc/AtWt23.html
similarity index 83%
rename from misc/AtWt19.html
rename to misc/AtWt23.html
index bd2ad10..0a85c0b 100644
--- a/misc/AtWt19.html
+++ b/misc/AtWt23.html
@@ -1,5 +1,5 @@
-<html><head><title>2019 Atomic Weights</title>
-<base href="https://www.qmul.ac.uk/sbcs/iupac/AtWt/index.html">
+<html><head><title>2023 Atomic Weights</title>
+<base href="https://iupac.qmul.ac.uk/AtWt/index.html">
 <meta name="keywords" content="IUPAC atomic weight relative atomic mass">
 <meta name="description" content="The full text of the IUPAC table of atomic weights">
 <meta name="object type" content="document">
@@ -7,15 +7,15 @@
 
 <center><b><a href="http://www.ciaaw.org">IUPAC Commission on Isotopic Abundances and Atomic Weights</a>.</b><p>
 
-<h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
+<h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2023</b></h1><p>
 
-These tables are based on the <a href="AtWt15.html">2015 table</a> with changes from the 2015 table for the values of aluminium, argon, cobalt, gold, holmium, iridium, manganese, niobium, praseodymium, protactinium, rhodium, terbium, thulium and yttrium. See <a href="http://iupac.org/standard-atomic-weights-of-14-chemical-elements-revised/">report 5 June 2018</a>. The revised value of hafnium was reported <a href="https://iupac.org/standard-atomic-weight-of-hafnium-revised/">11 December 2019</a><p>
+These tables are based on the <a href="https://doi.org/10.1515/pac-2019-0603">2021 table</a> with changes from the 2019 table for the values of Ar, Hf, Ir, Pb and Yb and changes to the uncertainty for Al, Au, Co, F, Ho, Mn, Nb, Pa, Pr, Rh, Sc, Tb, Tm, and Y. The values of<a href="https://iupac.org/standard-atomic-weights-of-three-technology-critical-elements-revised/"> Gd, Lu and Zr were revised and published in 2024</a>.<p>
 
-<span style="color: #ff000"><b>https://www.qmul.ac.uk/sbcs/iupac/AtWt/ </b></span></center><p>
+<span style="color: #ff000"><b>https://iupac.qmul.ac.uk/AtWt/ </b></span></center><p>
 
 World Wide Web version of atomic weight data originally prepared by <a href="mailto:g.p.moss@qmul.ac.uk">G. P. Moss</a>, from a file provided by D. R. Lide.<p>
 
-Previous values may be consulted from the <a href = "AtWt93.html">1993 table</a>, the <a href = "AtWt95.html">1995 table</a>, the <a href = "AtWt97.html">1997 table</a>, the <a href = "AtWt99.html">1999 table</a>, the <a href = "AtWt01.html">2001 table</a>, the <a href = "AtWt05.html">2005 table</a>, the <a href = "AtWt07.html">2007 table</a>, the <a href = "AtWt09.html">2009 table</a>, the <a href = "AtWt11.html">2011 table</a>, the  <a href = "AtWt13.html">2013 table</a> or the <a href = "AtWt15.html">2015 table</a>.<p>
+Previous values may be consulted from the <a href = "AtWt93.html">1993 table</a>, the <a href = "AtWt95.html">1995 table</a>, the <a href = "AtWt97.html">1997 table</a>, the <a href = "AtWt99.html">1999 table</a>, the <a href = "AtWt01.html">2001 table</a>, the <a href = "AtWt05.html">2005 table</a>, the <a href = "AtWt07.html">2007 table</a>, the <a href = "AtWt09.html">2009 table</a>, the <a href = "AtWt11.html">2011 table</a>, the  <a href = "AtWt13.html">2013 table</a>, the <a href = "AtWt15.html">2015 table</a>, <a href = "AtWt19.html">2019 table or the <a href = "AtWt21.html">2021 table</a>.<p>
 
 The standard atomic weights of twelve elements having two or more stable isotopes have  variability of atomic-weight values in natural terrestrial materials. These are given in <a href="#01">table 1</a> below. In the other lists the values quoted are those suggested for material where the origin of the sample is unknown. For radioactive elements the isotope with the longest half-life is quoted in parenthesis. The original paper should be consulted for full details of the variation in atomic weight and the half life of the radioisotopes quoted below. <p>
 
@@ -45,34 +45,34 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>82</td><td>Pb</td><td>lead</td><td>206.14</td><td>207.94</td></tr>
 </table></center><p>
 
-See original paper for the range of these elements from different sources [Isotope-abundance variations and atomic weights of selected elements: 2016 (IUPAC Technical Report), <a href="https://www.degruyter.com/view/j/pac.2016.88.issue-12/pac-2016-0302/pac-2016-0302.xml"><i>Pure Appl. Chem.</i> 2016, <b>88</b>(12), 1203-1224.</a> and <a href="https://www.degruyter.com/document/doi/10.1515/pac-2018-0916/html"> <i>Pure Appl. Chem.</i> 2021, <b>93</b>(1), 155-166</a>]<p>
+See original paper for the range of these elements from different sources [Isotope-abundance variations and atomic weights of selected elements: 2016 (IUPAC Technical Report), <a href="https://www.degruyter.com/view/j/pac.2016.88.issue-12/pac-2016-0302/pac-2016-0302.xml"><i>Pure Appl. Chem.</i> 2016, <b>88</b>(12), 1203-1224.</a>, <a href="https://www.degruyter.com/document/doi/10.1515/pac-2018-0916/html"> <i>Pure Appl. Chem.</i> 2021, <b>93</b>(1), 155-166</a> and <a href=" https://doi.org/10.1515/pac-2019-0603"><i>Pure Appl. Chem.</i> 2022, <b>94</b></a>]<p>
 
 
 <center><a name="02"><h3><b>Table 2. List of Elements in Atomic Number Order.</b></h3></a><p>
  
 <table border=0 cellspace=13 cellpadding=0>
 <tr><td>At No &nbsp; &nbsp; </td><td>Symbol &nbsp; &nbsp; </td><td>Name</td><td>Atomic Wt</td><td>Notes</td></tr>
-<tr><td>1</td><td>H</td><td>Hydrogen</td><td>1.008</td><td>3, 5</td></tr>
+<tr><td>1</td><td>H</td><td>Hydrogen</td><td>1.0080(2)</td><td>3, 5</td></tr>
 <tr><td>2</td><td>He</td><td>Helium</td><td>4.002 602(2)</td><td>1, 2</td></tr>
-<tr><td>3</td><td>Li</td><td>Lithium</td><td>6.94</td><td>3, 5</td></tr>
+<tr><td>3</td><td>Li</td><td>Lithium</td><td>6.94(6)</td><td>3, 5</td></tr>
 <tr><td>4</td><td>Be</td><td>Beryllium</td><td>9.012 1831(5)</td></tr>
-<tr><td>5</td><td>B</td><td>Boron</td><td>10.81</td><td>3, 5</td></tr>
-<tr><td>6</td><td>C</td><td>Carbon</td><td>12.011</td><td>5</td></tr>
-<tr><td>7</td><td>N</td><td>Nitrogen</td><td>14.007</td><td>5</td></tr>
-<tr><td>8</td><td>O</td><td>Oxygen</td><td>15.999</td><td>5</td></tr>
-<tr><td>9</td><td>F</td><td>Fluorine</td><td>18.998 403 163(6)</td></tr>
+<tr><td>5</td><td>B</td><td>Boron</td><td>10.81(2)</td><td>3, 5</td></tr>
+<tr><td>6</td><td>C</td><td>Carbon</td><td>12.011(2)</td><td>5</td></tr>
+<tr><td>7</td><td>N</td><td>Nitrogen</td><td>14.007(1)</td><td>5</td></tr>
+<tr><td>8</td><td>O</td><td>Oxygen</td><td>15.999(1)</td><td>5</td></tr>
+<tr><td>9</td><td>F</td><td>Fluorine</td><td>18.998 403 162(5)</td></tr>
 <tr><td>10</td><td>Ne</td><td>Neon</td><td>20.1797(6)</td><td>1, 3</td></tr>
 <tr><td>11</td><td>Na</td><td>Sodium</td><td>22.989 769 28(2) &nbsp; &nbsp; </td></tr>
-<tr><td>12</td><td>Mg</td><td>Magnesium</td><td>24.305</td><td>5</td></tr>
+<tr><td>12</td><td>Mg</td><td>Magnesium</td><td>24.305(2)</td><td>5</td></tr>
 <tr><td>13</td><td>Al</td><td>Aluminium</td><td>26.981 5384(3)</td></tr>
-<tr><td>14</td><td>Si</td><td>Silicon</td><td>28.085</td><td>5</td></tr>
-<tr><td>15</td><td>P</td><td>Phosphorus</td><td>30.973 761 998(5)</td></tr>
-<tr><td>16</td><td>S</td><td>Sulfur</td><td>32.06</td><td>5</td></tr>
-<tr><td>17</td><td>Cl</td><td>Chlorine</td><td>35.45</td><td>3, 5</td></tr>
-<tr><td>18</td><td>Ar</td><td>Argon</td><td>39.948(1)</td><td>1, 2, 5</td></tr>
+<tr><td>14</td><td>Si</td><td>Silicon</td><td>28.085(1)</td><td>5</td></tr>
+<tr><td>15</td><td>P</td><td>Phosphorus</td><td>(30.973 761 998(5)</td></tr>
+<tr><td>16</td><td>S</td><td>Sulfur</td><td>32.06(2)</td><td>5</td></tr>
+<tr><td>17</td><td>Cl</td><td>Chlorine</td><td>35.45(1)</td><td>3, 5</td></tr>
+<tr><td>18</td><td>Ar</td><td>Argon</td><td>39.95(16)</td><td>1, 2, 5</td></tr>
 <tr><td>19</td><td>K</td><td>Potassium</td><td>39.0983(1)</td><td></td></tr>
 <tr><td>20</td><td>Ca</td><td>Calcium</td><td>40.078(4)</td><td></td></tr>
-<tr><td>21</td><td>Sc</td><td>Scandium</td><td>44.955 908(5)</td></tr>
+<tr><td>21</td><td>Sc</td><td>Scandium</td><td>44.955 907(4)</td></tr>
 <tr><td>22</td><td>Ti</td><td>Titanium</td><td>47.867(1)</td></tr>
 <tr><td>23</td><td>V</td><td>Vanadium</td><td>50.9415(1)</td></tr>
 <tr><td>24</td><td>Cr</td><td>Chromium</td><td>51.9961(6)</td></tr>
@@ -86,12 +86,12 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>32</td><td>Ge</td><td>Germanium</td><td>72.630(8)</td></tr>
 <tr><td>33</td><td>As</td><td>Arsenic</td><td>74.921 595(6)</td></tr>
 <tr><td>34</td><td>Se</td><td>Selenium</td><td>78.971(8)</td></tr>
-<tr><td>35</td><td>Br</td><td>Bromine</td><td>79.904</td><td>5</td></tr>
+<tr><td>35</td><td>Br</td><td>Bromine</td><td>79.904(3)_</td><td>5</td></tr>
 <tr><td>36</td><td>Kr</td><td>Krypton</td><td>83.798(2)</td><td>1, 3</td></tr>
 <tr><td>37</td><td>Rb</td><td>Rubidium</td><td>85.4678(3)</td><td>1</td></tr>
 <tr><td>38</td><td>Sr</td><td>Strontium</td><td>87.62(1)</td><td>1, 2</td></tr>
-<tr><td>39</td><td>Y</td><td>Yttrium</td><td>88.905 84(1)</td></tr>
-<tr><td>40</td><td>Zr</td><td>Zirconium</td><td>91.224(2)</td><td>1</td></tr>
+<tr><td>39</td><td>Y</td><td>Yttrium</td><td>88.905 838(2)</td></tr>
+<tr><td>40</td><td>Zr</td><td>Zirconium</td><td>91.222(3)</td><td>1</td></tr>
 <tr><td>41</td><td>Nb</td><td>Niobium</td><td>92.906 37(1)</td></tr>
 <tr><td>42</td><td>Mo</td><td>Molybdenum</td><td>95.95(1)</td><td>1</td></tr>
 <tr><td>43</td><td>Tc</td><td>Technetium</td><td>[97]</td><td>4</td></tr>
@@ -115,14 +115,14 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>61</td><td>Pm</td><td>Promethium</td><td>[145]</td><td></td></tr>
 <tr><td>62</td><td>Sm</td><td>Samarium</td><td>150.36(2)</td><td>1</td></tr>
 <tr><td>63</td><td>Eu</td><td>Europium</td><td>151.964(1)</td><td>1</td></tr>
-<tr><td>64</td><td>Gd</td><td>Gadolinium</td><td>157.25(3)</td><td>1</td></tr>
-<tr><td>65</td><td>Tb</td><td>Terbium</td><td>158.925 354(8)</td></tr>
+<tr><td>64</td><td>Gd</td><td>Gadolinium</td><td>157.249(2)</td><td>1</td></tr>
+<tr><td>65</td><td>Tb</td><td>Terbium</td><td>158.925 354(7)</td></tr>
 <tr><td>66</td><td>Dy</td><td>Dysprosium</td><td>162.500(1)</td><td>1</td></tr>
-<tr><td>67</td><td>Ho</td><td>Holmium</td><td>164.930 328(7)</td></tr>
+<tr><td>67</td><td>Ho</td><td>Holmium</td><td>164.930 329(5)</td></tr>
 <tr><td>68</td><td>Er</td><td>Erbium</td><td>167.259(3)</td><td>1</td></tr>
-<tr><td>69</td><td>Tm</td><td>Thulium</td><td>168.934 218(6)</td></tr>
+<tr><td>69</td><td>Tm</td><td>Thulium</td><td>168.934 219(5)</td></tr>
 <tr><td>70</td><td>Yb</td><td>Ytterbium</td><td>173.045(10)</td><td>1</td></tr>
-<tr><td>71</td><td>Lu</td><td>Lutetium</td><td>174.9668(1)</td><td>1</td></tr>
+<tr><td>71</td><td>Lu</td><td>Lutetium</td><td>174.966 69(5)</td><td>1</td></tr>
 <tr><td>72</td><td>Hf</td><td>Hafnium</td><td>178.486(6)</td></tr>
 <tr><td>73</td><td>Ta</td><td>Tantalum</td><td>180.947 88(2)</td></tr>
 <tr><td>74</td><td>W</td><td>Tungsten</td><td>183.84(1)</td></tr>
@@ -132,8 +132,8 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>78</td><td>Pt</td><td>Platinum</td><td>195.084(9)</td></tr>
 <tr><td>79</td><td>Au</td><td>Gold</td><td>196.966 570(4)</td></tr>
 <tr><td>80</td><td>Hg</td><td>Mercury</td><td>200.592(3)</td></tr>
-<tr><td>81</td><td>Tl</td><td>Thallium</td><td>204.38</td><td>5</td></tr>
-<tr><td>82</td><td>Pb</td><td>Lead</td><td>207.2(1)</td><td>1, 2, 5</td></tr>
+<tr><td>81</td><td>Tl</td><td>Thallium</td><td>204.38(1)</td><td>5</td></tr>
+<tr><td>82</td><td>Pb</td><td>Lead</td><td>207.2(1.1)</td><td>1, 2, 5</td></tr>
 <tr><td>83</td><td>Bi</td><td>Bismuth</td><td>208.980 40(1)</td></tr>
 <tr><td>84</td><td>Po</td><td>Polonium</td><td>[209]</td><td>4</td></tr>
 <tr><td>85</td><td>At</td><td>Astatine</td><td>[210]</td><td>4</td></tr>
@@ -196,7 +196,7 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>13</td><td>Al</td><td>Aluminium</td><td>26.981 5384(3)</td></tr>
 <tr><td>95</td><td>Am</td><td>Americium</td><td>[243]</td><td>4</td></tr>
 <tr><td>51</td><td>Sb</td><td>Antimony</td><td>121.760(1)</td><td>1 </td></tr>
-<tr><td>18</td><td>Ar</td><td>Argon</td><td>39.948(1)</td><td>1, 2, 5</td></tr>
+<tr><td>18</td><td>Ar</td><td>Argon</td><td>39.95(16)</td><td>1, 2, 5</td></tr>
 <tr><td>33</td><td>As</td><td>Arsenic</td><td>74.921 595(6)</td></tr>
 <tr><td>85</td><td>At</td><td>Astatine</td><td>[210]</td><td>4</td></tr>
 <tr><td>56</td><td>Ba</td><td>Barium</td><td>137.327(7)</td></tr>
@@ -204,13 +204,13 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>4</td><td>Be</td><td>Beryllium</td><td>9.012 1831(5)</td></tr>
 <tr><td>83</td><td>Bi</td><td>Bismuth</td><td>208.980 40(1)</td></tr>
 <tr><td>107</td><td>Bh</td><td>Bohrium</td><td>[270]</td><td>4</td></tr>
-<tr><td>5</td><td>B</td><td>Boron</td><td>10.81</td><td>3, 5</td></tr>
-<tr><td>35</td><td>Br</td><td>Bromine</td><td>79.904</td><td>5</td></tr>
+<tr><td>5</td><td>B</td><td>Boron</td><td>10.81(2)</td><td>3, 5</td></tr>
+<tr><td>35</td><td>Br</td><td>Bromine</td><td>79.904(3)</td><td>5</td></tr>
 <tr><td>48</td><td>Cd</td><td>Cadmium</td><td>112.414(4)</td><td>1 </td></tr>
 <tr><td>55</td><td>Cs</td><td>Caesium</td><td>132.905 451 96(6)</td></tr>
 <tr><td>20</td><td>Ca</td><td>Calcium</td><td>40.078(4)</td><td>1</td></tr>
 <tr><td>98</td><td>Cf</td><td>Californium</td><td>[251]</td><td>4</td></tr>
-<tr><td>6</td><td>C</td><td>Carbon</td><td>12.011</td><td>5</td></tr>
+<tr><td>6</td><td>C</td><td>Carbon</td><td>12.011(2)</td><td>5</td></tr>
 <tr><td>58</td><td>Ce</td><td>Cerium</td><td>140.116(1)</td><td>1</td></tr>
 <tr><td>17</td><td>Cl</td><td>Chlorine</td><td>35.45</td><td>3, 5</td></tr>
 <tr><td>24</td><td>Cr</td><td>Chromium</td><td>51.9961(6)</td></tr>
@@ -226,16 +226,16 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>63</td><td>Eu</td><td>Europium</td><td>151.964(1)</td><td>1</td></tr>
 <tr><td>100</td><td>Fm</td><td>Fermium</td><td>[257]</td><td>4</td></tr>
 <tr><td>114</td><td>Fl</td><td>Flerovium</td><td>[289]</td><td>4</td></tr>
-<tr><td>9</td><td>F</td><td>Fluorine</td><td>18.998 403 163(6)</td></tr>
+<tr><td>9</td><td>F</td><td>Fluorine</td><td>18.998 403 162(5)</td></tr>
 <tr><td>87</td><td>Fr</td><td>Francium</td><td>[223]</td><td>4</td></tr>
-<tr><td>64</td><td>Gd</td><td>Gadolinium</td><td>157.25(3)</td><td>1</td></tr>
+<tr><td>64</td><td>Gd</td><td>Gadolinium</td><td>157.249(2)</td><td>1</td></tr>
 <tr><td>31</td><td>Ga</td><td>Gallium</td><td>69.723(1)</td></tr>
 <tr><td>32</td><td>Ge</td><td>Germanium</td><td>72.630(8)</td></tr>
 <tr><td>79</td><td>Au</td><td>Gold</td><td>196.966 570(4)</td></tr>
 <tr><td>72</td><td>Hf</td><td>Hafnium</td><td>178.486(6)</td></tr>
 <tr><td>108</td><td>Hs</td><td>Hassium</td><td>[270]</td><td>4</td></tr>
 <tr><td>2</td><td>He</td><td>Helium</td><td>4.002 602(2)</td><td>1, 2</td></tr>
-<tr><td>67</td><td>Ho</td><td>Holmium</td><td>164.930 328(7)</td></tr>
+<tr><td>67</td><td>Ho</td><td>Holmium</td><td>164.930 329(5)</td></tr>
 <tr><td>1</td><td>H</td><td>Hydrogen</td><td>1.008</td><td>3, 5</td></tr>
 <tr><td>49</td><td>In</td><td>Indium</td><td>114.818(1)</td></tr>
 <tr><td>53</td><td>I</td><td>Iodine</td><td>126.904 47(3)</td></tr>
@@ -244,11 +244,11 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>36</td><td>Kr</td><td>Krypton</td><td>83.798(2)</td><td>1, 3</td></tr>
 <tr><td>57</td><td>La</td><td>Lanthanum</td><td>138.905 47(7)</td><td>1</td></tr>
 <tr><td>103</td><td>Lr</td><td>Lawrencium</td><td>[262]</td><td>4</td></tr>
-<tr><td>82</td><td>Pb</td><td>Lead</td><td>207.2(1)</td><td>1, 2, 5</td></tr>
+<tr><td>82</td><td>Pb</td><td>Lead</td><td>207.2(1.1)</td><td>1, 2, 5</td></tr>
 <tr><td>3</td><td>Li</td><td>Lithium</td><td>6.94</td><td>3, 5</td></tr>
 <tr><td>116</td><td>Lv</td><td>Livermorium</td><td>[293]</td><td>4</td></tr>
-<tr><td>71</td><td>Lu</td><td>Lutetium</td><td>174.9668(1)</td><td>1</td></tr>
-<tr><td>12</td><td>Mg</td><td>Magnesium</td><td>24.305</td><td>5</td></tr>
+<tr><td>71</td><td>Lu</td><td>Lutetium</td><td>174.966 69(5)</td><td>1</td></tr>
+<tr><td>12</td><td>Mg</td><td>Magnesium</td><td>24.305(2)</td><td>5</td></tr>
 <tr><td>25</td><td>Mn</td><td>Manganese</td><td>54.938 043(2)</td></tr>
 <tr><td>109</td><td>Mt</td><td>Meitnerium</td><td>[278]</td><td>4</td></tr>
 <tr><td>101</td><td>Md</td><td>Mendelevium</td><td>[258]</td><td>4</td></tr>
@@ -261,11 +261,11 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>28</td><td>Ni</td><td>Nickel</td><td>58.6934(4)</td></tr>
 <tr><td>113</td><td>Nh</td><td>Nihonium </td><td>[286]</td><td>4</td></tr>
 <tr><td>41</td><td>Nb</td><td>Niobium</td><td>92.906 37(1)</td></tr>
-<tr><td>7</td><td>N</td><td>Nitrogen</td><td>14.007</td><td>5</td></tr>
+<tr><td>7</td><td>N</td><td>Nitrogen</td><td>14.007(1)</td><td>5</td></tr>
 <tr><td>102</td><td>No</td><td>Nobelium</td><td>[259]</td><td>4</td></tr>
 <tr><td>118</td><td>Og</td><td>Oganesson</td><td>[294]</td><td>4</td></tr>
 <tr><td>76</td><td>Os</td><td>Osmium</td><td>190.23(3)</td><td>1</td></tr>
-<tr><td>8</td><td>O</td><td>Oxygen</td><td>15.999</td><td>5</td></tr>
+<tr><td>8</td><td>O</td><td>Oxygen</td><td>15.999(1)</td><td>5</td></tr>
 <tr><td>46</td><td>Pd</td><td>Palladium</td><td>106.42(1)</td><td>1</td></tr>
 <tr><td>15</td><td>P</td><td>Phosphorus</td><td>30.973 761 998(5)</td></tr>
 <tr><td>78</td><td>Pt</td><td>Platinum</td><td>195.084(9)</td></tr>
@@ -284,22 +284,22 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>44</td><td>Ru</td><td>Ruthenium</td><td>101.07(2)</td><td>1</td></tr>
 <tr><td>104</td><td>Rf</td><td>Rutherfordium</td><td>[267]</td><td>4</td></tr>
 <tr><td>62</td><td>Sm</td><td>Samarium</td><td>150.36(2)</td><td>1 </td></tr>
-<tr><td>21</td><td>Sc</td><td>Scandium</td><td>44.955 908(5)</td></tr>
+<tr><td>21</td><td>Sc</td><td>Scandium</td><td>44.955 907(4)</td></tr>
 <tr><td>106</td><td>Sg</td><td>Seaborgium</td><td>[269]</td><td>4</td></tr>
 <tr><td>34</td><td>Se</td><td>Selenium</td><td>78.971(8)</td></tr>
-<tr><td>14</td><td>Si</td><td>Silicon</td><td>28.085</td><td>5</td></tr>
+<tr><td>14</td><td>Si</td><td>Silicon</td><td>28.085(1)</td><td>5</td></tr>
 <tr><td>47</td><td>Ag</td><td>Silver</td><td>107.8682(2)</td><td>1</td></tr>
 <tr><td>11</td><td>Na</td><td>Sodium</td><td>22.989 769 28(2) &nbsp; &nbsp; </td></tr>
 <tr><td>38</td><td>Sr</td><td>Strontium</td><td>87.62(1)</td><td>1, 2</td></tr>
-<tr><td>16</td><td>S</td><td>Sulfur</td><td>32.06</td><td>5</td></tr>
+<tr><td>16</td><td>S</td><td>Sulfur</td><td>32.06(2)</td><td>5</td></tr>
 <tr><td>73</td><td>Ta</td><td>Tantalum</td><td>180.947 88(2)</td></tr>
 <tr><td>43</td><td>Tc</td><td>Technetium</td><td>[97]</td><td>4</td></tr>
 <tr><td>52</td><td>Te</td><td>Tellurium</td><td>127.60(3)</td><td>1</td></tr>
 <tr><td>117</td><td>Ts</td><td>Tennessine</td><td>[293]</td><td>4</td></tr>
-<tr><td>65</td><td>Tb</td><td>Terbium</td><td>158.925 354(8)</td></tr>
-<tr><td>81</td><td>Tl</td><td>Thallium</td><td>204.38</td><td>5</td></tr>
+<tr><td>65</td><td>Tb</td><td>Terbium</td><td>158.925 354(7)</td></tr>
+<tr><td>81</td><td>Tl</td><td>Thallium</td><td>204.38(1)</td><td>5</td></tr>
 <tr><td>90</td><td>Th</td><td>Thorium</td><td>232.0377(4)</td><td>1, 4</td></tr> 
-<tr><td>69</td><td>Tm</td><td>Thulium</td><td>168.934 218(6)</td></tr>
+<tr><td>69</td><td>Tm</td><td>Thulium</td><td>168.934 219(5)</td></tr>
 <tr><td>50</td><td>Sn</td><td>Tin</td><td>118.710(7)</td><td>1</td></tr>
 <tr><td>22</td><td>Ti</td><td>Titanium</td><td>47.867(1)</td></tr>
 <tr><td>74</td><td>W</td><td>Tungsten</td><td>183.84(1)</td></tr>
@@ -307,9 +307,9 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 <tr><td>23</td><td>V</td><td>Vanadium</td><td>50.9415(1)</td></tr>
 <tr><td>54</td><td>Xe</td><td>Xenon</td><td>131.293(6)</td><td>1, 3</td></tr>
 <tr><td>70</td><td>Yb</td><td>Ytterbium</td><td>173.045(10)</td><td>1</td></tr>
-<tr><td>39</td><td>Y</td><td>Yttrium</td><td>88.905 84(1)</td></tr>
+<tr><td>39</td><td>Y</td><td>Yttrium</td><td>88.905 838(2)</td></tr>
 <tr><td>30</td><td>Zn</td><td>Zinc</td><td>65.38(2)</td><td>2</td></tr>
-<tr><td>40</td><td>Zr</td><td>Zirconium</td><td>91.224(2)</td><td>1</td></tr>
+<tr><td>40</td><td>Zr</td><td>Zirconium</td><td>91.222(3)</td><td>1</td></tr>
 </table></center>
 
 <ol>
@@ -318,7 +318,7 @@ <h1><b>ATOMIC WEIGHTS OF THE ELEMENTS 2019</b></h1><p>
 
 <li>Range in isotopic composition of normal terrestrial material prevents a more precise value being given; the tabulated value should be applicable to any normal material.
 
-<li>Modified isotopic compositions may be found in commercially available material because it has been subject to an undisclosed or inadvertant isotopic fractionation. Substantial deviations in atomic weight of the element from that given in the Table can occur.
+<li>Modified isotopic compositions may be found in commercially available material because it has been subject to an undisclosed or inadvertent isotopic fractionation. Substantial deviations in atomic weight of the element from that given in the Table can occur.
 
 <li>Element has no stable nuclides. The value enclosed in brackets, e.g. [209], indicates the mass number of the longest-lived isotope of the element. However three such elements (Th, Pa, and U) do have a characteristic terrestrial isotopic composition, and for these an atomic weight is tabulated.
 
diff --git a/pyproject.toml b/pyproject.toml
index 97b13ec..6a4bfd4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "chemformula"
-version = "1.3.1"
+version = "1.4.0"
 description = "ChemFormula is a Python class for working with chemical formulas. It allows parsing chemical formulas, generating formatted output strings and calculating formula weights."
 readme = "README.md"
 authors = [
diff --git a/src/chemformula/elements.py b/src/chemformula/elements.py
index d1b47d5..0e508e5 100644
--- a/src/chemformula/elements.py
+++ b/src/chemformula/elements.py
@@ -1,5 +1,5 @@
 '''
-ATOMIC WEIGHTS OF THE ELEMENTS (2019)
+ATOMIC WEIGHTS OF THE ELEMENTS (2023)
 from the IUPAC Commission on Isotopic Abundances and Atomic Weights
 
 Based on the following reports:
@@ -10,8 +10,10 @@
     - Pure Appl. Chem., 2016, 88, 1225-1229 (https://doi.org/10.1515/pac-2016-0501)
     - Chem. Int., 2018, 40(4), 23-24        (https://doi.org/10.1515/ci-2018-0409)
     - Chem. Int., 2020, 42(2), 31           (https://doi.org/10.1515/ci-2020-0222)
+    - Pure Appl. Chem., 2022, 94(5), 573-600 (https://doi.org/10.1515/pac-2019-0603)
+    - Chem. Int., 2025, 47(1), 20-20         (https://doi.org/10.1515/ci-2025-0105)
 
-Data taken from: https://www.qmul.ac.uk/sbcs/iupac/AtWt/
+Data taken from: https://iupac.qmul.ac.uk/AtWt/
 
 Quoted atomic weights are those suggested for materials where the origin of the sample is unknown.
 For radioactive elements the isotope with the longest half-life is quoted as an integer.
@@ -28,7 +30,7 @@ def atomic_weight(element):
         "C":   12.011,
         "N":   14.007,
         "O":   15.999,
-        "F":   18.998403163,
+        "F":   18.998403162,
         "Ne":  20.1797,
         "Na":  22.98976928,
         "Mg":  24.305,
@@ -37,10 +39,10 @@ def atomic_weight(element):
         "P":   30.973761998,
         "S":   32.06,
         "Cl":  35.45,
-        "Ar":  39.948,
+        "Ar":  39.95,
         "K":   39.0983,
         "Ca":  40.078,
-        "Sc":  44.955908,
+        "Sc":  44.955907,
         "Ti":  47.867,
         "V":   50.9415,
         "Cr":  51.9961,
@@ -58,8 +60,8 @@ def atomic_weight(element):
         "Kr":  83.798,
         "Rb":  85.4678,
         "Sr":  87.62,
-        "Y":   88.90584,
-        "Zr":  91.224,
+        "Y":   88.905838,
+        "Zr":  91.222,
         "Nb":  92.90637,
         "Mo":  95.95,
         "Tc":  97,
@@ -83,14 +85,14 @@ def atomic_weight(element):
         "Pm": 145,
         "Sm": 150.36,
         "Eu": 151.964,
-        "Gd": 157.25,
+        "Gd": 157.249,
         "Tb": 158.925354,
         "Dy": 162.500,
-        "Ho": 164.930328,
+        "Ho": 164.930329,
         "Er": 167.259,
-        "Tm": 168.934218,
+        "Tm": 168.934219,
         "Yb": 173.045,
-        "Lu": 174.9668,
+        "Lu": 174.96669,
         "Hf": 178.486,
         "Ta": 180.94788,
         "W":  183.84,
diff --git a/uv.lock b/uv.lock
index 080b7a5..4eca76d 100644
--- a/uv.lock
+++ b/uv.lock
@@ -13,7 +13,7 @@ wheels = [
 
 [[package]]
 name = "chemformula"
-version = "1.3.1"
+version = "1.4.0"
 source = { editable = "." }
 dependencies = [
     { name = "casregnum" },

At No	Symbol	Name	Atomic Wt	Notes
1	H	Hydrogen	1.008	3, 5
1	H	Hydrogen	1.0080(2)	3, 5
2	He	Helium	4.002 602(2)	1, 2
3	Li	Lithium	6.94	3, 5
3	Li	Lithium	6.94(6)	3, 5
4	Be	Beryllium	9.012 1831(5)
5	B	Boron	10.81	3, 5
6	C	Carbon	12.011	5
7	N	Nitrogen	14.007	5
8	O	Oxygen	15.999	5
9	F	Fluorine	18.998 403 163(6)
5	B	Boron	10.81(2)	3, 5
6	C	Carbon	12.011(2)	5
7	N	Nitrogen	14.007(1)	5
8	O	Oxygen	15.999(1)	5
9	F	Fluorine	18.998 403 162(5)
10	Ne	Neon	20.1797(6)	1, 3
11	Na	Sodium	22.989 769 28(2)
12	Mg	Magnesium	24.305	5
12	Mg	Magnesium	24.305(2)	5
13	Al	Aluminium	26.981 5384(3)
14	Si	Silicon	28.085	5
15	P	Phosphorus	30.973 761 998(5)
16	S	Sulfur	32.06	5
17	Cl	Chlorine	35.45	3, 5
18	Ar	Argon	39.948(1)	1, 2, 5
14	Si	Silicon	28.085(1)	5
15	P	Phosphorus	(30.973 761 998(5)
16	S	Sulfur	32.06(2)	5
17	Cl	Chlorine	35.45(1)	3, 5
18	Ar	Argon	39.95(16)	1, 2, 5
19	K	Potassium	39.0983(1)
20	Ca	Calcium	40.078(4)
21	Sc	Scandium	44.955 908(5)
21	Sc	Scandium	44.955 907(4)
22	Ti	Titanium	47.867(1)
23	V	Vanadium	50.9415(1)
24	Cr	Chromium	51.9961(6)
32	Ge	Germanium	72.630(8)
33	As	Arsenic	74.921 595(6)
34	Se	Selenium	78.971(8)
35	Br	Bromine	79.904	5
35	Br	Bromine	79.904(3)_	5
36	Kr	Krypton	83.798(2)	1, 3
37	Rb	Rubidium	85.4678(3)	1
38	Sr	Strontium	87.62(1)	1, 2
39	Y	Yttrium	88.905 84(1)
40	Zr	Zirconium	91.224(2)	1
39	Y	Yttrium	88.905 838(2)
40	Zr	Zirconium	91.222(3)	1
41	Nb	Niobium	92.906 37(1)
42	Mo	Molybdenum	95.95(1)	1
43	Tc	Technetium	[97]	4
61	Pm	Promethium	[145]
62	Sm	Samarium	150.36(2)	1
63	Eu	Europium	151.964(1)	1
64	Gd	Gadolinium	157.25(3)	1
65	Tb	Terbium	158.925 354(8)
64	Gd	Gadolinium	157.249(2)	1
65	Tb	Terbium	158.925 354(7)
66	Dy	Dysprosium	162.500(1)	1
67	Ho	Holmium	164.930 328(7)
67	Ho	Holmium	164.930 329(5)
68	Er	Erbium	167.259(3)	1
69	Tm	Thulium	168.934 218(6)
69	Tm	Thulium	168.934 219(5)
70	Yb	Ytterbium	173.045(10)	1
71	Lu	Lutetium	174.9668(1)	1
71	Lu	Lutetium	174.966 69(5)	1
72	Hf	Hafnium	178.486(6)
73	Ta	Tantalum	180.947 88(2)
74	W	Tungsten	183.84(1)
78	Pt	Platinum	195.084(9)
79	Au	Gold	196.966 570(4)
80	Hg	Mercury	200.592(3)
81	Tl	Thallium	204.38	5
82	Pb	Lead	207.2(1)	1, 2, 5
81	Tl	Thallium	204.38(1)	5
82	Pb	Lead	207.2(1.1)	1, 2, 5
83	Bi	Bismuth	208.980 40(1)
84	Po	Polonium	[209]	4
85	At	Astatine	[210]	4
13	Al	Aluminium	26.981 5384(3)
95	Am	Americium	[243]	4
51	Sb	Antimony	121.760(1)	1
18	Ar	Argon	39.948(1)	1, 2, 5
18	Ar	Argon	39.95(16)	1, 2, 5
33	As	Arsenic	74.921 595(6)
85	At	Astatine	[210]	4
56	Ba	Barium	137.327(7)
4	Be	Beryllium	9.012 1831(5)
83	Bi	Bismuth	208.980 40(1)
107	Bh	Bohrium	[270]	4
5	B	Boron	10.81	3, 5
35	Br	Bromine	79.904	5
5	B	Boron	10.81(2)	3, 5
35	Br	Bromine	79.904(3)	5
48	Cd	Cadmium	112.414(4)	1
55	Cs	Caesium	132.905 451 96(6)
20	Ca	Calcium	40.078(4)	1
98	Cf	Californium	[251]	4
6	C	Carbon	12.011	5
6	C	Carbon	12.011(2)	5
58	Ce	Cerium	140.116(1)	1
17	Cl	Chlorine	35.45	3, 5
24	Cr	Chromium	51.9961(6)
63	Eu	Europium	151.964(1)	1
100	Fm	Fermium	[257]	4
114	Fl	Flerovium	[289]	4
9	F	Fluorine	18.998 403 163(6)
9	F	Fluorine	18.998 403 162(5)
87	Fr	Francium	[223]	4
64	Gd	Gadolinium	157.25(3)	1
64	Gd	Gadolinium	157.249(2)	1
31	Ga	Gallium	69.723(1)
32	Ge	Germanium	72.630(8)
79	Au	Gold	196.966 570(4)
72	Hf	Hafnium	178.486(6)
108	Hs	Hassium	[270]	4
2	He	Helium	4.002 602(2)	1, 2
67	Ho	Holmium	164.930 328(7)
67	Ho	Holmium	164.930 329(5)
1	H	Hydrogen	1.008	3, 5
49	In	Indium	114.818(1)
53	I	Iodine	126.904 47(3)
36	Kr	Krypton	83.798(2)	1, 3
57	La	Lanthanum	138.905 47(7)	1
103	Lr	Lawrencium	[262]	4
82	Pb	Lead	207.2(1)	1, 2, 5
82	Pb	Lead	207.2(1.1)	1, 2, 5
3	Li	Lithium	6.94	3, 5
116	Lv	Livermorium	[293]	4
71	Lu	Lutetium	174.9668(1)	1
12	Mg	Magnesium	24.305	5
71	Lu	Lutetium	174.966 69(5)	1
12	Mg	Magnesium	24.305(2)	5
25	Mn	Manganese	54.938 043(2)
109	Mt	Meitnerium	[278]	4
101	Md	Mendelevium	[258]	4
28	Ni	Nickel	58.6934(4)
113	Nh	Nihonium	[286]	4
41	Nb	Niobium	92.906 37(1)
7	N	Nitrogen	14.007	5
7	N	Nitrogen	14.007(1)	5
102	No	Nobelium	[259]	4
118	Og	Oganesson	[294]	4
76	Os	Osmium	190.23(3)	1
8	O	Oxygen	15.999	5
8	O	Oxygen	15.999(1)	5
46	Pd	Palladium	106.42(1)	1
15	P	Phosphorus	30.973 761 998(5)
78	Pt	Platinum	195.084(9)
44	Ru	Ruthenium	101.07(2)	1
104	Rf	Rutherfordium	[267]	4
62	Sm	Samarium	150.36(2)	1
21	Sc	Scandium	44.955 908(5)
21	Sc	Scandium	44.955 907(4)
106	Sg	Seaborgium	[269]	4
34	Se	Selenium	78.971(8)
14	Si	Silicon	28.085	5
14	Si	Silicon	28.085(1)	5
47	Ag	Silver	107.8682(2)	1
11	Na	Sodium	22.989 769 28(2)
38	Sr	Strontium	87.62(1)	1, 2
16	S	Sulfur	32.06	5
16	S	Sulfur	32.06(2)	5
73	Ta	Tantalum	180.947 88(2)
43	Tc	Technetium	[97]	4
52	Te	Tellurium	127.60(3)	1
117	Ts	Tennessine	[293]	4
65	Tb	Terbium	158.925 354(8)
81	Tl	Thallium	204.38	5
65	Tb	Terbium	158.925 354(7)
81	Tl	Thallium	204.38(1)	5
90	Th	Thorium	232.0377(4)	1, 4
69	Tm	Thulium	168.934 218(6)
69	Tm	Thulium	168.934 219(5)
50	Sn	Tin	118.710(7)	1
22	Ti	Titanium	47.867(1)
74	W	Tungsten	183.84(1)
23	V	Vanadium	50.9415(1)
54	Xe	Xenon	131.293(6)	1, 3
70	Yb	Ytterbium	173.045(10)	1
39	Y	Yttrium	88.905 84(1)
39	Y	Yttrium	88.905 838(2)
30	Zn	Zinc	65.38(2)	2
40	Zr	Zirconium	91.224(2)	1
40	Zr	Zirconium	91.222(3)	1