Symbol (chemistry)

In relation to the chemical elements, a symbol is a code for a chemical element.[nb 1] Many functional groups has their own chemical symbol, e.g. Ph for the phenyl group, and Me for the methyl group. Chemical symbols for elements normally consist of one or two letters from the Latin alphabet, but can contain three when the element has a systematic temporary name (as of March 2017, no discovered elements have such a name), and are written with the first letter capitalized.

Earlier chemical element symbols stem from classical Latin and Greek vocabulary. For some elements, this is because the material was known in ancient times, while for others, the name is a more recent invention. For example, "He" is the symbol for helium (New Latin name, not known in ancient Roman times), "Pb" for lead (plumbum in Latin), and "Hg" for mercury (hydrargyrum in Greek). Some symbols come from other sources, like "W" for tungsten (Wolfram in German, not known in Roman times).

Temporary symbols assigned to newly or not-yet synthesized elements use 3-letter symbols based on their atomic numbers. For example, "Uno" was the temporary symbol for hassium (element 108) which had the temporary name of unniloctium.

Chemical symbols may be modified by the use of prepended superscripts or subscripts to specify a particular isotope of an atom. Additionally, appended superscripts may be used to indicate the ionization or oxidation state of an element. They are widely used in chemistry and they have been officially chosen by the International Union of Pure and Applied Chemistry. There are also some historical symbols that are no longer officially used.

This is an example of an atomic symbol. The text boxes explain where the numbers are derived from.

Attached subscripts or superscripts specifying a nucleotide or molecule have the following meanings and positions:

In Chinese each chemical element has a dedicated character, usually created for the purpose (see Chemical elements in East Asian languages). However, Latin symbols are also used, especially in formulas.

The periodic table, elements being denoted by their symbols

A list of current, dated, as well as proposed and historical signs and symbols is included here with its signification. Also given is each element's atomic number, atomic weight or the atomic mass of the most stable isotope, group and period numbers on the periodic table, and etymology of the symbol.

Hazard pictographs are another type of symbols used in chemistry.

Symbols for chemical elements

List of chemical elements
Z[upper-roman 1] Symbol Element Origin of name[1][2] Group Period Atomic weight[3][4] (u (±)) Density (g/cm3) Melt (K) [5] Boil (K) C[upper-roman 1] (J/g · K) χ[upper-roman 1] Abundance in Earth's crust[upper-roman 2] (mg/kg)
1 H Hydrogen composed of the Greek elements hydro- and -gen meaning 'water-forming' 1 1 1.008[upper-roman 3][upper-roman 4][upper-roman 5][upper-roman 6] 0.00008988 14.01 20.28 14.304 2.20 1400
2 He Helium the Greek helios, 'sun' 18 1 4.002602(2)[upper-roman 3][upper-roman 5] 0.0001785 —[upper-roman 7] 4.22 5.193 – 0.008
3 Li Lithium the Greek lithos, 'stone' 1 2 6.94[upper-roman 3][upper-roman 4][upper-roman 5][upper-roman 8][upper-roman 6] 0.534 453.69 1560 3.582 0.98 20
4 Be Beryllium beryl, a mineral 2 2 9.0121831(5) 1.85 1560 2742 1.825 1.57 2.8
5 B Boron borax, a mineral 13 2 10.81[upper-roman 3][upper-roman 4][upper-roman 5][upper-roman 6] 2.34 2349 4200 1.026 2.04 10
6 C Carbon the Latin carbo, 'coal' 14 2 12.011[upper-roman 3][upper-roman 5][upper-roman 6] 2.267 3800 4300 0.709 2.55 200
7 N Nitrogen the Greek nitron and '-gen' meaning 'niter-forming' 15 2 14.007[upper-roman 3][upper-roman 5][upper-roman 6] 0.0012506 63.15 77.36 1.04 3.04 19
8 O Oxygen from the Greek oxy-, both 'sharp' and 'acid', and -gen, meaning 'acid-forming' 16 2 15.999[upper-roman 3][upper-roman 5][upper-roman 6] 0.001429 54.36 90.20 0.918 3.44 461000
9 F Fluorine the Latin fluere, 'to flow' 17 2 18.998403163(6) 0.001696 53.53 85.03 0.824 3.98 585
10 Ne Neon the Greek neos, meaning 'new' 18 2 20.1797(6)[upper-roman 3][upper-roman 4] 0.0008999 24.56 27.07 1.03 – 0.005
11 Na Sodium the English word soda (natrium in Latin) 1 3 22.98976928(2) 0.971 370.87 1156 1.228 0.93 23600
12 Mg Magnesium Magnesia, a district of Eastern Thessaly in Greece 2 3 24.305[upper-roman 6] 1.738 923 1363 1.023 1.31 23300
13 Al Aluminium from alumina, a compound (originally aluminum) 13 3 26.9815385(7) 2.698 933.47 2792 0.897 1.61 82300
14 Si Silicon from the Latin silex, 'flint' (originally silicium) 14 3 28.085[upper-roman 5][upper-roman 6] 2.3296 1687 3538 0.705 1.9 282000
15 P Phosphorus the Greek phoosphoros, 'carrying light' 15 3 30.973761998(5) 1.82 317.30 550 0.769 2.19 1050
16 S Sulfur the Latin sulphur, 'fire and brimstone' 16 3 32.06[upper-roman 3][upper-roman 5][upper-roman 6] 2.067 388.36 717.87 0.71 2.58 350
17 Cl Chlorine the Greek chloros, 'greenish yellow' 17 3 35.45[upper-roman 3][upper-roman 4][upper-roman 5][upper-roman 6] 0.003214 171.6 239.11 0.479 3.16 145
18 Ar Argon the Greek argos, 'idle' 18 3 39.948(1)[upper-roman 3][upper-roman 5] 0.0017837 83.80 87.30 0.52 – 3.5
19 K Potassium New Latin potassa, 'potash' (kalium in Latin) 1 4 39.0983(1) 0.862 336.53 1032 0.757 0.82 20900
20 Ca Calcium the Latin calx, 'lime' 2 4 40.078(4)[upper-roman 3] 1.54 1115 1757 0.647 1 41500
21 Sc Scandium Scandia, the Latin name for Scandinavia 3 4 44.955908(5) 2.989 1814 3109 0.568 1.36 22
22 Ti Titanium Titans, the sons of the Earth goddess of Greek mythology 4 4 47.867(1) 4.54 1941 3560 0.523 1.54 5650
23 V Vanadium Vanadis, an Old Norse name for the Scandinavian goddess Freyja 5 4 50.9415(1) 6.11 2183 3680 0.489 1.63 120
24 Cr Chromium the Greek chroma, 'color' 6 4 51.9961(6) 7.15 2180 2944 0.449 1.66 102
25 Mn Manganese corrupted from magnesia negra, see Magnesium 7 4 54.938044(3) 7.44 1519 2334 0.479 1.55 950
26 Fe Iron English word (ferrum in Latin) 8 4 55.845(2) 7.874 1811 3134 0.449 1.83 56300
27 Co Cobalt the German word Kobold, 'goblin' 9 4 58.933194(4) 8.86 1768 3200 0.421 1.88 25
28 Ni Nickel from Swedish kopparnickel, containing the German word Nickel, 'goblin' 10 4 58.6934(4) 8.912 1728 3186 0.444 1.91 84
29 Cu Copper English word (Latin cuprum) 11 4 63.546(3)[upper-roman 5] 8.96 1357.77 2835 0.385 1.9 60
30 Zn Zinc the German Zink 12 4 65.38(2) 7.134 692.88 1180 0.388 1.65 70
31 Ga Gallium Gallia, the Latin name for France 13 4 69.723(1) 5.907 302.9146 2673 0.371 1.81 19
32 Ge Germanium Germania, the Latin name for Germany 14 4 72.630(8) 5.323 1211.40 3106 0.32 2.01 1.5
33 As Arsenic English word (Latin arsenicum) 15 4 74.921595(6) 5.776 1090 [upper-roman 9] 887 0.329 2.18 1.8
34 Se Selenium the Greek selene, 'moon' 16 4 78.971(8)[upper-roman 5] 4.809 453 958 0.321 2.55 0.05
35 Br Bromine the Greek bromos, 'stench' 17 4 79.904[upper-roman 6] 3.122 265.8 332.0 0.474 2.96 2.4
36 Kr Krypton the Greek kryptos, 'hidden' 18 4 83.798(2)[upper-roman 3][upper-roman 4] 0.003733 115.79 119.93 0.248 3 1×10−4
37 Rb Rubidium the Latin rubidus, 'deep red' 1 5 85.4678(3)[upper-roman 3] 1.532 312.46 961 0.363 0.82 90
38 Sr Strontium Strontian, a small town in Scotland 2 5 87.62(1)[upper-roman 3][upper-roman 5] 2.64 1050 1655 0.301 0.95 370
39 Y Yttrium Ytterby, Sweden 3 5 88.90584(2) 4.469 1799 3609 0.298 1.22 33
40 Zr Zirconium Persian Zargun, 'gold-colored'; German Zirkoon, 'jargoon' 4 5 91.224(2)[upper-roman 3] 6.506 2128 4682 0.278 1.33 165
41 Nb Niobium Niobe, daughter of king Tantalus from Greek mythology 5 5 92.90637(2) 8.57 2750 5017 0.265 1.6 20
42 Mo Molybdenum the Greek molybdos meaning 'lead' 6 5 95.95(1)[upper-roman 3] 10.22 2896 4912 0.251 2.16 1.2
43 Tc Technetium the Greek tekhnètos meaning 'artificial' 7 5 [98][upper-roman 10] 11.5 2430 4538 – 1.9 ~ 3×10−9[upper-roman 11]
44 Ru Ruthenium Ruthenia, the New Latin name for Russia 8 5 101.07(2)[upper-roman 3] 12.37 2607 4423 0.238 2.2 0.001
45 Rh Rhodium the Greek rhodos, meaning 'rose coloured' 9 5 102.90550(2) 12.41 2237 3968 0.243 2.28 0.001
46 Pd Palladium the then recently discovered asteroid Pallas, considered a planet at the time 10 5 106.42(1)[upper-roman 3] 12.02 1828.05 3236 0.244 2.2 0.015
47 Ag Silver English word (argentum in Latin) 11 5 107.8682(2)[upper-roman 3] 10.501 1234.93 2435 0.235 1.93 0.075
48 Cd Cadmium the New Latin cadmia, from King Kadmos 12 5 112.414(4)[upper-roman 3] 8.69 594.22 1040 0.232 1.69 0.159
49 In Indium indigo 13 5 114.818(1) 7.31 429.75 2345 0.233 1.78 0.25
50 Sn Tin English word (stannum in Latin) 14 5 118.710(7)[upper-roman 3] 7.287 505.08 2875 0.228 1.96 2.3
51 Sb Antimony uncertain: perhaps from the Greek anti, 'against', and monos, 'alone', or the Old French antimoine, 'Monk's bane' (stibium in Latin) 15 5 121.760(1)[upper-roman 3] 6.685 903.78 1860 0.207 2.05 0.2
52 Te Tellurium Latin tellus, 'earth' 16 5 127.60(3)[upper-roman 3] 6.232 722.66 1261 0.202 2.1 0.001
53 I Iodine French iode (after the Greek ioeides, 'violet') 17 5 126.90447(3) 4.93 386.85 457.4 0.214 2.66 0.45
54 Xe Xenon the Greek xenos, 'strange' 18 5 131.293(6)[upper-roman 3][upper-roman 4] 0.005887 161.4 165.03 0.158 2.6 3×10−5
55 Cs Caesium the Latin caesius, 'sky blue' 1 6 132.90545196(6) 1.873 301.59 944 0.242 0.79 3
56 Ba Barium the Greek barys, 'heavy' 2 6 137.327(7) 3.594 1000 2170 0.204 0.89 425
57 La Lanthanum the Greek lanthanein, 'to lie hidden' 3 6 138.90547(7)[upper-roman 3] 6.145 1193 3737 0.195 1.1 39
58 Ce Cerium the then recently discovered asteroid Ceres, considered a planet at the time 6 140.116(1)[upper-roman 3] 6.77 1068 3716 0.192 1.12 66.5
59 Pr Praseodymium the Greek praseios didymos meaning 'green twin' 6 140.90766(2) 6.773 1208 3793 0.193 1.13 9.2
60 Nd Neodymium the Greek neos didymos meaning 'new twin' 6 144.242(3)[upper-roman 3] 7.007 1297 3347 0.19 1.14 41.5
61 Pm Promethium Prometheus of Greek mythology who stole fire from the Gods and gave it to humans 6 [145][upper-roman 10] 7.26 1315 3273 – 1.13 2×10−19[upper-roman 11]
62 Sm Samarium Samarskite, the name of the mineral from which it was first isolated 6 150.36(2)[upper-roman 3] 7.52 1345 2067 0.197 1.17 7.05
63 Eu Europium Europe 6 151.964(1)[upper-roman 3] 5.243 1099 1802 0.182 1.2 2
64 Gd Gadolinium Johan Gadolin, chemist, physicist and mineralogist 6 157.25(3)[upper-roman 3] 7.895 1585 3546 0.236 1.2 6.2
65 Tb Terbium Ytterby, Sweden 6 158.92535(2) 8.229 1629 3503 0.182 1.2 1.2
66 Dy Dysprosium the Greek dysprositos, 'hard to get' 6 162.500(1)[upper-roman 3] 8.55 1680 2840 0.17 1.22 5.2
67 Ho Holmium Holmia, the New Latin name for Stockholm 6 164.93033(2) 8.795 1734 2993 0.165 1.23 1.3
68 Er Erbium Ytterby, Sweden 6 167.259(3)[upper-roman 3] 9.066 1802 3141 0.168 1.24 3.5
69 Tm Thulium Thule, the ancient name for Scandinavia 6 168.93422(2) 9.321 1818 2223 0.16 1.25 0.52
70 Yb Ytterbium Ytterby, Sweden 6 173.045(10)[upper-roman 3] 6.965 1097 1469 0.155 1.1 3.2
71 Lu Lutetium Lutetia, the Latin name for Paris 6 174.9668(1)[upper-roman 3] 9.84 1925 3675 0.154 1.27 0.8
72 Hf Hafnium Hafnia, the New Latin name for Copenhagen 4 6 178.49(2) 13.31 2506 4876 0.144 1.3 3
73 Ta Tantalum King Tantalus, father of Niobe from Greek mythology 5 6 180.94788(2) 16.654 3290 5731 0.14 1.5 2
74 W Tungsten the Swedish tung sten, 'heavy stone' (W is wolfram, the old name of the tungsten mineral wolframite) 6 6 183.84(1) 19.25 3695 5828 0.132 2.36 1.3
75 Re Rhenium Rhenus, the Latin name for the river Rhine 7 6 186.207(1) 21.02 3459 5869 0.137 1.9 7×10−4
76 Os Osmium the Greek osmè, meaning 'smell' 8 6 190.23(3)[upper-roman 3] 22.61 3306 5285 0.13 2.2 0.002
77 Ir Iridium Iris, the Greek goddess of the rainbow 9 6 192.217(3) 22.56 2719 4701 0.131 2.2 0.001
78 Pt Platinum the Spanish platina, meaning 'little silver' 10 6 195.084(9) 21.46 2041.4 4098 0.133 2.28 0.005
79 Au Gold English word (aurum in Latin) 11 6 196.966569(5) 19.282 1337.33 3129 0.129 2.54 0.004
80 Hg Mercury the New Latin name mercurius, named after the Roman god (Hg from former name hydrargyrum, from Greek hydr-, 'water', and argyros, 'silver') 12 6 200.592(3) 13.5336 234.43 629.88 0.14 2 0.085
81 Tl Thallium the Greek thallos, 'green twig' 13 6 204.38[upper-roman 6] 11.85 577 1746 0.129 1.62 0.85
82 Pb Lead English word (plumbum in Latin) 14 6 207.2(1)[upper-roman 3][upper-roman 5] 11.342 600.61 2022 0.129 1.87 14
83 Bi Bismuth Uncertain, possibly Arabic or German 15 6 208.98040(1)[upper-roman 10] 9.807 544.7 1837 0.122 2.02 0.009
84 Po Polonium Named after the home country of Marie Curie (Polonia, Latin for Poland), who is also the discoverer of Radium 16 6 [209][upper-roman 10] 9.32 527 1235 – 2.0 2×10−10[upper-roman 11]
85 At Astatine the Greek astatos, 'unstable' 17 6 [210][upper-roman 10] 7 575 610 – 2.2 3×10−20[upper-roman 11]
86 Rn Radon From radium, as it was first detected as an emission from radium during radioactive decay 18 6 [222][upper-roman 10] 0.00973 202 211.3 0.094 2.2 4×10−13[upper-roman 11]
87 Fr Francium Francia, the New Latin name for France 1 7 [223][upper-roman 10] 1.87 300 950 – 0.7 ~ 1×10−18[upper-roman 11]
88 Ra Radium the Latin radius, 'ray' 2 7 [226][upper-roman 10] 5.5 973 2010 0.094 0.9 9×10−7[upper-roman 11]
89 Ac Actinium the Greek aktis, 'ray' 3 7 [227][upper-roman 10] 10.07 1323 3471 0.12 1.1 5.5×10−10[upper-roman 11]
90 Th Thorium Thor, the Scandinavian god of thunder 7 232.0377(4)[upper-roman 10][upper-roman 3] 11.72 2115 5061 0.113 1.3 9.6
91 Pa Protactinium the Greek protos, 'first', and actinium, which is produced through the radioactive decay of protactinium 7 231.03588(2)[upper-roman 10] 15.37 1841 4300 – 1.5 1.4×10−6[upper-roman 11]
92 U Uranium Uranus, the seventh planet in the Solar System 7 238.02891(3)[upper-roman 10] 18.95 1405.3 4404 0.116 1.38 2.7
93 Np Neptunium Neptune, the eighth planet in the Solar System 7 [237][upper-roman 10] 20.45 917 4273 – 1.36 ≤ 3×10−12[upper-roman 11]
94 Pu Plutonium Pluto, a dwarf planet in the Solar System (then considered the ninth planet) 7 [244][upper-roman 10] 19.84 912.5 3501 – 1.28 ≤ 3×10−11[upper-roman 11]
95 Am Americium The Americas, as the element was first synthesized on the continent, by analogy with europium 7 [243][upper-roman 10] 13.69 1449 2880 – 1.13 0[upper-roman 12]
96 Cm Curium Pierre Curie, a physicist, and Marie Curie, a physicist and chemist, named after great scientists by analogy with gadolinium 7 [247][upper-roman 10] 13.51 1613 3383 – 1.28 0[upper-roman 12]
97 Bk Berkelium Berkeley, California, where the element was first synthesized, by analogy with terbium 7 [247][upper-roman 10] 14.79 1259 2900 – 1.3 0[upper-roman 12]
98 Cf Californium California, where the element was first synthesized 7 [251][upper-roman 10] 15.1 1173 (1743)[upper-roman 13] – 1.3 0[upper-roman 12]
99 Es Einsteinium Albert Einstein, physicist 7 [252][upper-roman 10] 8.84 1133 (1269)[upper-roman 13] – 1.3 0[upper-roman 12]
100 Fm Fermium Enrico Fermi, physicist 7 [257][upper-roman 10] (9.7)[upper-roman 13] (1125)[upper-roman 13] – – 1.3 0[upper-roman 12]
101 Md Mendelevium Dmitri Mendeleev, chemist and inventor 7 [258][upper-roman 10] (10.3)[upper-roman 13] (1100)[upper-roman 13] – – 1.3 0[upper-roman 12]
102 No Nobelium Alfred Nobel, chemist, engineer, innovator, and armaments manufacturer 7 [259][upper-roman 10] (9.9)[upper-roman 13] (1100)[upper-roman 13] – – 1.3 0[upper-roman 12]
103 Lr Lawrencium Ernest O. Lawrence, physicist 7 [266][upper-roman 10] (15.6)[upper-roman 13] (1900)[upper-roman 13] – – 1.3 0[upper-roman 12]
104 Rf Rutherfordium Ernest Rutherford, chemist and physicist 4 7 [267][upper-roman 10] (23.2)[upper-roman 13] (2400)[upper-roman 13] (5800)[upper-roman 13] – – 0[upper-roman 12]
105 Db Dubnium Dubna, Russia 5 7 [268][upper-roman 10] (29.3)[upper-roman 13] – – – – 0[upper-roman 12]
106 Sg Seaborgium Glenn T. Seaborg, scientist 6 7 [269][upper-roman 10] (35.0)[upper-roman 13] – – – – 0[upper-roman 12]
107 Bh Bohrium Niels Bohr, physicist 7 7 [270][upper-roman 10] (37.1)[upper-roman 13] – – – – 0[upper-roman 12]
108 Hs Hassium Hesse, Germany, where the element was first synthesized 8 7 [277][upper-roman 10] (40.7)[upper-roman 13] – – – – 0[upper-roman 12]
109 Mt Meitnerium Lise Meitner, physicist 9 7 [278][upper-roman 10] (37.4)[upper-roman 13] – – – – 0[upper-roman 12]
110 Ds Darmstadtium Darmstadt, Germany, where the element was first synthesized 10 7 [281][upper-roman 10] (34.8)[upper-roman 13] – – – – 0[upper-roman 12]
111 Rg Roentgenium Wilhelm Conrad Röntgen, physicist 11 7 [282][upper-roman 10] (28.7)[upper-roman 13] – – – – 0[upper-roman 12]
112 Cn Copernicium Nicolaus Copernicus, astronomer 12 7 [285][upper-roman 10] (23.7)[upper-roman 13] – ~357[upper-roman 14] – – 0[upper-roman 12]
113 Nh Nihonium the Japanese name for Japan, Nihon, where the element was first synthesized 13 7 [286][upper-roman 10] (16)[upper-roman 13] (700)[upper-roman 13] (1400)[upper-roman 13] – – 0[upper-roman 12]
114 Fl Flerovium Flerov Laboratory of Nuclear Reactions, part of JINR where the element was synthesized; itself named for Georgy Flyorov, physicist 14 7 [289][upper-roman 10] (14)[upper-roman 13] – ~210 – – 0[upper-roman 12]
115 Mc Moscovium Moscow Oblast, Russia, where the element was first synthesized 15 7 [290][upper-roman 10] (13.5)[upper-roman 13] (700)[upper-roman 13] (1400)[upper-roman 13] – – 0[upper-roman 12]
116 Lv Livermorium Lawrence Livermore National Laboratory (in Livermore, California) which collaborated with JINR on its synthesis 16 7 [293][upper-roman 10] (12.9)[upper-roman 13] (709)[upper-roman 13] (1085)[upper-roman 13] – – 0[upper-roman 12]
117 Ts Tennessine Tennessee, United States 17 7 [294][upper-roman 10] (7.2)[upper-roman 13] (723)[upper-roman 13] (883)[upper-roman 13] – – 0[upper-roman 12]
118 Og Oganesson Yuri Oganessian, physicist 18 7 [294][upper-roman 10] (5.0)[upper-roman 13][upper-roman 15] – (350)[upper-roman 13] – – 0[upper-roman 12]

Notes

  1. 1 2 3 Z is the standard symbol for atomic number; C is the standard symbol for heat capacity; and χ is the standard symbol for electronegativity on the Pauling scale.
  2. ↑ Unless otherwise indicated, elements are primordial – they occur naturally, and not through decay.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 The isotopic composition of this element varies in some geological specimens, and the variation may exceed the uncertainty stated in the table.
  4. 1 2 3 4 5 6 7 The isotopic composition of the element can vary in commercial materials, which can cause the atomic weight to deviate significantly from the given value.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 The isotopic composition varies in terrestrial material such that a more precise atomic weight can not be given.
  6. 1 2 3 4 5 6 7 8 9 10 11 12 The value listed is the conventional atomic-weight value suitable for trade and commerce. The actual value may differ depending on the isotopic composition of the sample. Since 2009, IUPAC provides the standard atomic-weight values for these elements using the interval notation. The corresponding standard atomic weights are:
    • Hydrogen: [1.00784, 1.00811]
    • Lithium: [6.938, 6.997]
    • Boron: [10.806, 10.821]
    • Carbon: [12.0096, 12.0116]
    • Nitrogen: [14.00643, 14.00728]
    • Oxygen: [15.99903, 15.99977]
    • Magnesium: [24.304, 24.307]
    • Silicon: [28.084, 28.086]
    • Sulfur: [32.059, 32.076]
    • Chlorine: [35.446, 35.457]
    • Bromine: [79.901, 79.907]
    • Thallium: [204.382, 204.385]
  7. ↑ This element does not solidify at a pressure of one atmosphere. Helium can only solidify at pressures above 25 atmospheres, which corresponds to a melting point of absolute zero.
  8. ↑ The atomic weight of commercial lithium can vary between 6.939 and 6.996—analysis of the specific material is necessary to find a more accurate value.
  9. ↑ This element sublimes at one atmosphere of pressure.
  10. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 The element does not have any stable nuclides, and a value in brackets, e.g. [209], indicates the mass number of the longest-lived isotope of the element. However, four such elements, bismuth, thorium, protactinium, and uranium, have characteristic terrestrial isotopic compositions, and thus their standard atomic weights are given.
  11. 1 2 3 4 5 6 7 8 9 10 11 This element is transient – it occurs only through decay.
  12. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 This element is synthetic – the transuranic elements 95 and above do not occur naturally, but they can all be produced artificially.
  13. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 The value has not been precisely measured, usually because of the element's short half-life; the value given in parentheses is a prediction.
  14. ↑ With error bars: 357+112
    −108     K.
  15. ↑ This predicted value is for liquid oganesson, not gaseous oganesson.

Antimatter atoms are denoted by a bar above the symbol for their matter counterpart, so e.g. H is the symbol for antihydrogen.

Symbols and names not currently used

The following is a list of symbols and names formerly used or suggested for elements, including symbols for placeholder names and names given by discredited claimants for discovery.

Chemical symbolNameAtomic numberOrigin of symbolWhy not usedRefs
AArgon18A used for Argon until 1957. Current symbol is Ar. [nb 2] [6]
AbAlabamine85Discredited claim to discovery of astatine. [nb 3] [7]
AdAldebaranium70Former name for ytterbium. [nb 3]
AmAlabamium85Discredited claim to discovery of astatine. The symbol is now used for americium.[nb 3] [7]
AnAthenium99Proposed name for einsteinium. [nb 4]
AoAusonium93Discredited claim to discovery of neptunium. [nb 3] [7]
AzAzote7Former name for nitrogen. [nb 2]
BoBoron5Current symbol is B. [nb 2]
BvBrevium91Former name for protactinium. [nb 2]
BzBerzelium Baskerville wrongly believed berzelium to be a new element. Was actually thorium. [nb 4] [8]
CbColumbium41Former name for niobium. [nb 2] [7][8]
ChChromium24Current symbol is Cr. [nb 2]
ClColumbium41Former name for niobium. The symbol is now used for chlorine. [nb 2]
CnCarolinium Baskerville wrongly believed carolinium to be a new element. Was actually thorium. The symbol is now used for copernicium. [8]
CpCassiopeium71Former name for lutetium. [nb 2]
CpCopernicium112Current symbol is Cn. [nb 2]
CtCeltium72Discredited claim to discovery of hafnium. [nb 3]
CtCenturium100Proposed name for fermium. [nb 4]
DDidymium Mixture of the elements praseodymium and neodymium. Mosander wrongly believed didymium to be an element. [9]
DaDavyum43Discredited claim to discovery of technetium. [nb 3] [7]
DbDubnium104Proposed name for rutherfordium. The symbol and name were instead used for element 105. [nb 2][nb 4] [7]
DiDidymium Mixture of the elements praseodymium and neodymium. Mosander wrongly believed didymium to be an element. [9]
DsDysprosium66Current symbol is Dy. The symbol is now used for darmstadtium. [nb 2]
EEinsteinium99Current symbol is Es. [nb 2]
EErbium68Current symbol is Er. [nb 2]
EaEkaaluminium31Name given by Mendeleev to an as of then undiscovered element. When discovered, gallium closely matched the prediction. [nb 4][nb 5]
EbEkaboron21Name given by Mendeleev to an as of then undiscovered element. When discovered, scandium closely matched the prediction. [nb 4][nb 5] [7]
ElEkaaluminium31Name given by Mendeleev to an as of then undiscovered element. When discovered, gallium closely matched the prediction. [nb 4][nb 5] [7]
EmEkamanganese43Name given by Mendeleev to an as of then undiscovered element. When discovered, technetium closely matched the prediction. [nb 4][nb 5] [7]
EmEmanation86Also called "radium emanation", the name was originally given by Friedrich Ernst Dorn in 1900. In 1923, this element officially became radon (the name given at one time to 222Rn, an isotope identified in the decay chain of radium). [nb 2] [7]
EmEmanium89Alternate name formerly proposed for actinium. [nb 4]
EsEkasilicon32Name given by Mendeleev to an as of then undiscovered element. When discovered, germanium closely matched the prediction. The symbol is now used for einsteinium. [nb 4][nb 5] [7]
EsEsperium94Discredited claim to discovery of plutonium. The symbol is now used for einsteinium. [nb 3] [7]
FaFrancium87Current symbol is Fr. [nb 2]
FlFlorentium61Discredited claim to discovery of promethium. The symbol is now used for flerovium. [nb 3]
FlFluorine9Current symbol is F. The symbol is now used for flerovium.[nb 2]
FrFlorentium61Discredited claim to discovery of promethium. The symbol is now used for francium. [nb 3] [7]
GGlucinium4Former name for beryllium. [nb 2]
GlGlucinium4Former name for beryllium. [nb 2] [7]
HaHahnium105Proposed name for dubnium. [nb 4]
HnHahnium108Proposed name for hassium. [nb 4] [7]
HvHelvetium85Discredited claim to discovery of astatine. [nb 3] [8]
HyMercury80Hy from the Greek hydrargyrum for "liquid silver". Current symbol is Hg. [nb 2] [6]
IIridium77Current symbol is Ir. The symbol is now used for iodine. [nb 2]
IlIllinium61Discredited claim to discovery of promethium. [nb 3] [7]
JJodium53Former name for iodine. [nb 2]
JgJargonium72Discredited claim to discovery of hafnium. [nb 3] [7]
JlJoliotium105Proposed name for dubnium. [nb 4] [7]
KaPotassium19Current symbol is K. [nb 2]
KuKurchatovium104Proposed name for rutherfordium. [nb 4] [7]
LLithium3Current symbol is Li. [nb 2]
LwLawrencium103Current symbol is Lr. [nb 2]
MMuriaticum17Former name for chlorine. [nb 2]
MaManganese25Current symbol is Mn. [nb 2]
MaMasurium43Disputed claim to discovery of technetium. [nb 3] [7]
MdMendelevium97Proposed name for berkelium. The symbol and name were later used for element 101. [nb 2][nb 4]
MlMoldavium87Discredited claim to discovery of francium. [nb 3] [8]
MsMagnesium12Current symbol is Mg. [nb 2]
MsMasrium88Discredited claim of discovery of radium. [nb 3]
MsMasurium43Disputed claim to discovery of technetium. [nb 3]
MvMendelevium101Current symbol is Md. [nb 2]
NgNorwegium72Discredited claim to discovery of hafnium. [nb 3]
NoNorium72Discredited claim to discovery of hafnium. The symbol is now used for nobelium. [nb 3]
NpNipponium43Discredited claim to discovery of technetium. The symbol is now used for neptunium. [nb 3] [7]
NsNielsbohrium105Proposed name for dubnium. [nb 4] [7]
NsNielsbohrium107Proposed name for bohrium. [nb 4] [7]
NtNiton86Former name for radon. [nb 2] [7]
NyNeoytterbium70Former name for ytterbium. [nb 2]
PLead82Current symbol is Pb. The symbol is now used for phosphorus. [nb 2]
PaPalladium46Current symbol is Pd. The symbol is now used for protactinium. [nb 2]
PePelopium41Former name for niobium. [nb 2]
PlPalladium46Current symbol is Pd. [nb 2]
PoPotassium19Current symbol is K. The symbol is now used for polonium. [nb 2]
RRhodium45Current symbol is Rh. [nb 2]
RdRadium88Current symbol is Ra. [nb 2]
RfRutherfordium106Proposed name for seaborgium. The symbol and name were instead used for element 104. [nb 2][nb 4] [7]
RoRhodium45Current symbol is Rh. [nb 2]
SaSamarium62Current symbol is Sm. [nb 2] [7]
SoSodium11Current symbol is Na. [nb 2]
StAntimony51Current symbol is Sb. [nb 2]
StTin50Current symbol is Sn. [nb 2]
TnTungsten74Current symbol is W. [nb 2]
TrTerbium65Current symbol is Tb. [nb 2]
TuThulium69Current symbol is Tm. [nb 2]
TuTungsten74Current symbol is W. [nb 2]
UnbUnnilbium102Temporary name given to nobelium until it was permanently named by IUPAC. [nb 5]
UneUnnilennium109Temporary name given to meitnerium until it was permanently named by IUPAC. [nb 5]
UnhUnnilhexium106Temporary name given to seaborgium until it was permanently named by IUPAC. [nb 5]
UnoUnniloctium108Temporary name given to hassium until it was permanently named by IUPAC. [nb 5]
UnpUnnilpentium105Temporary name given to dubnium until it was permanently named by IUPAC. [nb 5]
UnqUnnilquadium104Temporary name given to rutherfordium until it was permanently named by IUPAC. [nb 5]
UnsUnnilseptium107Temporary name given to bohrium until it was permanently named by IUPAC. [nb 5]
UntUnniltrium103Temporary name given to lawrencium until it was permanently named by IUPAC. [nb 5]
UnuUnnilunium101Temporary name given to mendelevium until it was permanently named by IUPAC. [nb 5]
UubUnunbium112Temporary name given to copernicium until it was permanently named by IUPAC. [nb 5]
UuhUnunhexium116Temporary name given to livermorium until it was permanently named by IUPAC. [nb 5]
UunUnunnilium110Temporary name given to darmstadtium until it was permanently named by IUPAC. [nb 5]
UuoUnunoctium118Temporary name given to oganesson until it was permanently named by IUPAC. [nb 5]
UupUnunpentium115Temporary name given to moscovium until it was permanently named by IUPAC. [nb 5]
UuqUnunquadium114Temporary name given to flerovium until it was permanently named by IUPAC. [nb 5]
UusUnunseptium117Temporary name given to tennessine until it was permanently named by IUPAC. [nb 5]
UutUnuntrium113Temporary name given to nihonium until it was permanently named by IUPAC. [nb 5]
UuuUnununium111Temporary name given to roentgenium until it was permanently named by IUPAC. [nb 5]
UrUranium92Current symbol is U. [nb 2]
ViVirginium87Discredited claim to discovery of francium. [nb 3] [7]
VmVirginium87Discredited claim to discovery of francium. [nb 3] [7]
VaVanadium23Current symbol is V. [nb 2]
WoTungsten74Current symbol is W. [nb 2]
XXenon54Current symbol is Xe. [nb 2]
YtYttrium39Current symbol is Y. [nb 2] [7]

Pictographic symbols

The following is a list of pictographic symbols employed to symbolize elements known since ancient times (for example to the alchemists). Not included in this list are symbolic representations of substances previously called elements (such as certain rare earth mineral blends and the classical elements fire and water of ancient philosophy) which are known today to be multi-atomic. Also not included are symbolic representations currently used for elements in other languages such as the Chinese characters for elements. Modern alphabetic notation was introduced in 1814 by Jöns Jakob Berzelius.

Chemical symbolOriginal nameModern nameAtomic numberOrigin of symbol
☉HydrogenHydrogen1Daltonian symbol circa 1808.
⬤CarbonCarbon6Daltonian symbol circa 1808.
⦶AzoteNitrogen7Daltonian symbol circa 1808.
◯OxygenOxygen8Daltonian symbol circa 1808.
⦷SodaSodium11Daltonian symbol circa 1808.
⊛MagnesiumMagnesium12Alchemical symbol.
SulfurSulfur16Alchemical symbol.
PallasSulfur16Alchemical symbol.
🜍SulfurSulfur16Alchemical symbol.
ⴲSulfurSulfur16Daltonian symbol circa 1808.
♂MarsIron26Alchemical symbol.
ⒾIronIron26Daltonian symbol circa 1808.
Stellae FixaeCopper29Pre–16th-century alchemical symbol.
♀VenusCopper29Alchemical symbol.
CopperCopper29Alchemical symbol.
ⒸCopperCopper29Daltonian symbol circa 1808.
ⓏZincZinc30Daltonian symbol circa 1808.
ArsenicArsenic33Alchemical symbol.
🜺ArsenicArsenic33Alchemical symbol.
☽LunaSilver47Alchemical symbol.
🜛SilverSilver47Alchemical symbol.
ⓈSilverSilver47Daltonian symbol circa 1808.
♃IupiterTin50Alchemical symbol.
♁AntimonyAntimony51Alchemical symbol.
☾PlatinumPlatinum78Alchemical symbol.
☉PlatinumPlatinum78Alchemical symbol.
⛢UranusPlatinum78Alchemical symbol.
☼SolGold79Alchemical symbol from the 16th century.
☉SolGold79Alchemical symbol from 1700 through 1783.
🜚GoldGold79Alchemical symbol.
♓PiscesMercury80Pre–16th-century alchemical symbol.
♆NeptunusMercury80Alchemical symbol from the 17th century.
☿MercuriusMercury80Alchemical symbol from 1700 through 1783.
♄SaturnusLead82Alchemical symbol circa 1783.
ⓁLeadLead82Daltonian symbol circa 1808.
♉TaurusBismuth83Alchemical symbol.

Symbols for named isotopes

The following is a list of isotopes of elements given in the previous tables which have been designated unique symbols. By this it is meant that a comprehensive list of current systematic symbols (in the uAtom form) are not included in the list and can instead be found in the Isotope index chart. The symbols for the named isotopes of hydrogen, deuterium (D) and tritium (T) are still in use today. Heavy water and other deuterated solvents are commonly used in chemistry, and it is convenient to use a single character rather than a symbol with a subscript in these cases. The practice also continues with tritium compounds. When the name of the solvent is given, a lowercase d is sometimes used. For example, d6-benzene and C6D6 can be used instead of [2H6]C6H6.[10]

The symbols for isotopes of elements other than hydrogen are no longer in use within the scientific community. Many of these symbols were designated during the early years of radiochemistry, and several isotopes (namely those in the actinium decay family, the radium decay family, and the thorium decay family) bear placeholder names using the early naming system devised by Ernest Rutherford.[11]

Chemical symbolNameAtomic numberOrigin of symbol
AcActinium89From the Greek aktinos. Name restricted at one time to 227Ac, an isotope of actinium. This named isotope later became the official name for element 89.
AcAActinium A84From actinium and A. Placeholder name given at one time to 215Po, an isotope of polonium identified in the decay chain of actinium.
AcBActinium B82From actinium and B. Placeholder name given at one time to 211Pb, an isotope of lead identified in the decay chain of actinium.
AcCActinium C83From actinium and C. Placeholder name given at one time to 211Bi, an isotope of bismuth identified in the decay chain of actinium.
AcC'Actinium C'84From actinium and C'. Placeholder name given at one time to 211Po, an isotope of polonium identified in the decay chain of actinium.
AcC"Actinium C"81From actinium and C". Placeholder name given at one time to 207Tl, an isotope of thallium identified in the decay chain of actinium.
AcKActinium K87Name given at one time to 223Fr, an isotope of francium identified in the decay chain of actinium.
AcUActino-uranium92Name given at one time to 235U, an isotope of uranium.
AcXActinium X88Name given at one time to 223Ra, an isotope of radium identified in the decay chain of actinium.
AnActinon86From actinium and emanation. Name given at one time to 219Rn, an isotope of radon identified in the decay chain of actinium.
DDeuterium1From the Greek deuteros. Name given to 2H.
IoIonium90Name given to 230Th, an isotope of thorium identified in the decay chain of uranium.
MsTh1Mesothorium 188Name given at one time to 228Ra, an isotope of radium.
MsTh2Mesothorium 289Name given at one time to 228Ac, an isotope of actinium.
PaProtactinium91From the Greek protos and actinium. Name restricted at one time to 231Pa, an isotope of protactinium. This named isotope later became the official name for element 91.
RaRadium88From the Latin radius. Name restricted at one time to 226Ra, an isotope of radium. This named isotope later became the official name for element 88.
RaARadium A84From radium and A. Placeholder name given at one time to 218Po, an isotope of polonium identified in the decay chain of radium.
RaBRadium B82From radium and B. Placeholder name given at one time to 214Pb, an isotope of lead identified in the decay chain of radium.
RaCRadium C83From radium and C. Placeholder name given at one time to 214Bi, an isotope of bismuth identified in the decay chain of radium.
RaC'Radium C'84From radium and C'. Placeholder name given at one time to 214Po, an isotope of polonium identified in the decay chain of radium.
RaC"Radium C"81From radium and C". Placeholder name given at one time to 210Tl, an isotope of thallium identified in the decay chain of radium.
RaDRadium D82From radium and D. Placeholder name given at one time to 210Pb, an isotope of lead identified in the decay chain of radium.
RaERadium E83From radium and E. Placeholder name given at one time to 210Bi, an isotope of bismuth identified in the decay chain of radium.
RaE"Radium E"81From radium and E". Placeholder name given at one time to 206Tl, an isotope of thallium identified in the decay chain of radium.
RaFRadium F84From radium and F. Placeholder name given at one time to 210Po, an isotope of polonium identified in the decay chain of radium.
RdAcRadioactinium90Name given at one time to 227Th, an isotope of thorium.
RdThRadiothorium90Name given at one time to 228Th, an isotope of thorium.
RnRadon86From radium and emanation. Name restricted at one time to 222Rn, an isotope of radon identified in the decay chain of radium. This named isotope later became the official name for element 86 in 1923.
TTritium1From the Greek tritos. Name given to 3H.
ThThorium90After Thor. Name restricted at one time to 232Th, an isotope of thorium. This named isotope later became the official name for element 90.
ThAThorium A84From thorium and A. Placeholder name given at one time to 216Po, an isotope of polonium identified in the decay chain of thorium.
ThBThorium B82From thorium and B. Placeholder name given at one time to 212Pb, an isotope of lead identified in the decay chain of thorium.
ThCThorium C83From thorium and C. Placeholder name given at one time to 212Bi, an isotope of bismuth identified in the decay chain of thorium.
ThC'Thorium C'84From thorium and C'. Placeholder name given at one time to 212Po, an isotope of polonium identified in the decay chain of thorium.
ThC"Thorium C"81From thorium and C". Placeholder name given at one time to 208Tl, an isotope of thallium identified in the decay chain of thorium.
ThXThorium X88Name given at one time to 224Ra, an isotope of radium identified in the decay chain of thorium.
TnThoron86From thorium and emanation. Name given at one time to 220Rn, an isotope of radon identified in the decay chain of thorium.
UIUranium I92Name given at one time to 238U, an isotope of uranium.
UIIUranium II92Name given at one time to 234U, an isotope of uranium.
UX1Uranium X190Name given at one time to 234Th, an isotope of thorium identified in the decay chain of uranium.
UX2Uranium X291Name given at one time to 234mPa, an isotope of protactinium identified in the decay chain of uranium.
UYUranium Y90Name given at one time to 231Th, an isotope of thorium identified in the decay chain of uranium.
UZUranium Z91Name given at one time to 234Pa, an isotope of protactinium identified in the decay chain of uranium.

Other symbols

See also Skeletal formula § Pseudoelement symbols.

General:

From organic chemistry:

Exotic atoms:

See also

Notes

  1. ↑ This should not be confused with formula. When a number is present at the bottom right corner of the symbol of the element, only then is it said to be a formula, but if the number is not present, it is a symbol.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 Name changed due to a standardization of, modernization of, or update to older formerly-used symbol.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Name designated by discredited/disputed claimant.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Name proposed prior to discovery/creation of element or prior to official re-naming of a placeholder name.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Temporary placeholder name.

References

  1. ↑ "Periodic Table – Royal Society of Chemistry". www.rsc.org.
  2. ↑ "Online Etymology Dictionary". etymonline.com.
  3. ↑ Wieser, Michael E.; et al. (2013). "Atomic weights of the elements 2011 (IUPAC Technical Report)". Pure Appl. Chem. IUPAC. 85 (5): 1047–1078. doi:10.1351/PAC-REP-13-03-02. (for standard atomic weights of elements)
  4. ↑ Sonzogni, Alejandro. "Interactive Chart of Nuclides". National Nuclear Data Center: Brookhaven National Laboratory. Retrieved 2008-06-06. (for atomic weights of elements with atomic numbers 103–118)
  5. ↑ Holman, S. W.; Lawrence, R. R.; Barr, L. (1 January 1895). "Melting Points of Aluminum, Silver, Gold, Copper, and Platinum". Proceedings of the American Academy of Arts and Sciences. 31: 218–233. doi:10.2307/20020628.
  6. 1 2 Holden, N. E. (12 March 2004). "History of the Origin of the Chemical Elements and Their Discoverers". National Nuclear Data Center.
  7. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19: 175–183. doi:10.1007/s10699-013-9326-y.
  8. 1 2 3 4 5 Fontani, Marco; Costa, Mariagrazia; Orna, Mary Virginia (2014). The Lost Elements: The Periodic Table's Shadow Side. Oxford University Press. ISBN 9780199383344.
  9. 1 2 Praseodymium. was.chemistryexplained.com.
  10. ↑ IUPAC. "Isotopically Modified Compounds". IUPAC. Retrieved 31 March 2015.
  11. ↑ Morgan, G. T., ed. (1905). "Annual Reports on the Progress of Chemistry for 1904". Journal of the Chemical Society. Gurney & Jackson. 1: 268. In view of the extraordinarily complex nature of the later changes occurring in Radium, Rutherford has proposed a new and convenient system of nomenclature. The first product of the change of the radium emanation is named radium A, the next radium B, and so on.
  12. ↑ Jurczyk, M.; Rajewski, W.; Majchrzycki, W.; Wójcik, G. (1999-08-30). "Mechanically alloyed MmNi5-type materials for metal hydride electrodes". Journal of Alloys and Compounds. 290 (1–2): 262–266. doi:10.1016/S0925-8388(99)00202-9.
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