Atomic Weights (IUPAC, 1971; based on "C = 12.000)'
Back to Index | Back to Studies | Back to Documents
|
Element
=
|
Weight
(AMU)
|
Element
=
|
Weight
(AMU)
|
Element
=
|
Weight
(AMU)
|
|
Aluminium
|
26.98154
|
Hydrogen
|
1.0079'
|
Rhenium
|
186.2
|
|
Antimony
|
121.75
|
Iridium
|
114.82
|
Rhodium
|
102.9055
|
|
Argon
|
39.948
b
|
Iodine
|
126.9045
|
Rubidium
|
85.4678
|
|
Arsenic
|
74.9216
|
Iridium
|
192.22
|
Ruthenium
|
101.07
|
|
Barium
|
137.34
|
Iron
|
55.847
|
Samarium
|
150.4
|
|
Beryllium
|
9.01218
|
Krypton
|
83.80
|
Scandium
|
44.9559
|
|
Bismuth |
208.9804
|
Lanthanum
|
138.9055
|
Selenium
|
78.96
|
|
Boron
|
10.81
b
|
Lead
|
207.2
b
|
Silicon
|
28.086
b
|
|
Bromine
|
79.904
|
Lithium
|
6.94
b
|
Silver
|
107.868
|
|
Cadmium
|
112.40
|
Lutetium
|
174.97
|
Sodium
|
22.98977
|
|
Calcium
|
40.08
|
Magnesium
|
24.305
|
Strontium
|
87.62
|
|
Carbon
|
12.011
b
|
Manganese
|
54.9380
|
Sulphur
|
32.06
b
|
|
Cerium |
140.12
|
Mercury
|
200.59
|
Tantalum
|
180.9479
|
|
Cesium
|
132.9054
|
Molybdenum
|
95.94
|
Technetium
|
98.9062d
|
|
Chlorine
|
35.453
|
Neodymium
|
144.24
|
Tellurium
|
127.60
|
|
Chromium
|
51.996
|
Neon
|
20.179
|
Terbium
|
158.9254
|
|
Cobalt
|
58.9332
|
Neptunium
|
237.0482
|
Thallium
|
204.37
|
|
Copper
|
63.546
b
|
Nickel
|
58.71
|
Thorium
|
232.0381
|
|
Dysprosium
|
162.50
|
Niobium
|
92.9064
|
Thulium
|
168.9342
|
|
Erbium |
167.26
|
Nitrogen
|
14.0067
|
Tin
|
118.69
|
|
Europium
|
151.96
|
Osmium
|
190.2
|
Titanium
|
47.90
|
|
Fluorine
|
18.9984
|
Oxygen
|
15.9994
b, c
|
Tungsten
|
183.85
|
|
Gadolinium
|
157.25
|
Palladium
|
106.4
|
Uranium
|
238.029c
|
|
Gallium
|
69.72
|
Phosphorus
|
30.97376
|
Vanadium
|
50.9414
|
|
Germanium |
72.59
|
Platinum
|
195.09
|
Xenon
|
131.30
|
|
Gold
|
196.9665
|
Potassium
|
39.098
|
Ytterbium
|
173.04
|
|
Hafnium
|
178.49
|
Praseodymium
|
140.0977
|
Yttrium
|
88.9059
|
|
Helium
|
4.00260
|
Protactinium
|
231.0359
|
Zinc
|
65.38e
|
|
Holmium
|
164.9304
|
Radium
|
226.0254
d
|
Zirconium
|
91.22
|
a Elements in materials of terrestrial origin. Reliable to ± 1 in last digit or ± 3 when subscript.
b Variation in natural isotopic abundance limits precision.
c Variations possible owing to artificial isotopic separation.
d Most commonly available long-lived isotope.
e A new coulometric determination gives 65.377 ± 0.003 (Chem. Eng. News, 1971, Sept. 27, p. 32).