Symbol (chemistry)

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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 (IUPAC). 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:

• The nucleon number (mass number) is shown in the left superscript position (e.g., ¹⁴N). This number defines the specific isotope. Various letters, such as "m" and "f" may also be used here to indicate a nuclear isomer (e.g., ^99mTc). Alternately, the number here can represent a specific spin state (e.g., ¹O₂). These details can be omitted if not relevant in a certain context.
• The proton number (atomic number) may be indicated in the left subscript position (e.g., ₆₄Gd). The atomic number is redundant to the chemical element, but is sometimes used to emphasize the change of numbers of nucleons in a nuclear reaction.
• If necessary, a state of ionization or an excited state may be indicated in the right superscript position (e.g., state of ionization Ca²⁺).
• The number of atoms of an element in a molecule or chemical compound is shown in the right subscript position (e.g., N₂ or Fe₂O₃). If this number is one, it is normally omitted - the number one is then implicit.
• A radical is indicated by a dot on the right side (e.g., Cl^• for a neutral chlorine atom). This is often omitted unless relevant to a certain context because it is already deducible from the charge and atomic number information values.

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.

Contents

• 1 Symbols for chemical elements
• 2 Symbols and names not currently used
  • 2.1 Pictographic symbols
• 3 Symbols for named isotopes
• 4 Other symbols
• 5 See also
• 6 Notes
• 7 References
• 8 External links

Symbols for chemical elements

[hide]List of chemical elements
Z[I]	Symbol	Element	Origin of name[1][2]	Group	Period	Atomic weight[3][4] (u (±))	Density (g/cm3)	Melt (K) [5]	Boil (K)	C[I] (J/g · K)	χ[I]	Abundance in Earth's crust[II] (mg/kg)
1	H	Hydrogen	composed of the Greek elements hydro- and -gen meaning 'water-forming'	1	1	1.008[III][IV][V][VI]	0.00008988	14.01	20.28	14.304	2.20	1400
2	He	Helium	the Greek helios, 'sun'	18	1	4.002602(2)[III][V]	0.0001785	—[VII]	4.22	5.193	–	0.008
3	Li	Lithium	the Greek lithos, 'stone'	1	2	6.94[III][IV][V][VIII][VI]	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[III][IV][V][VI]	2.34	2349	4200	1.026	2.04	10
6	C	Carbon	the Latin carbo, 'coal'	14	2	12.011[III][V][VI]	2.267	3800	4300	0.709	2.55	200
7	N	Nitrogen	the Greek nitron and '-gen' meaning 'niter-forming'	15	2	14.007[III][V][VI]	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[III][V][VI]	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)[III][IV]	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[VI]	1.738	923	1363	1.023	1.31	23300
13	Al	Aluminium	from alumina, a compound (originally alumium)	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[V][VI]	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[III][V][VI]	2.067	388.36	717.87	0.71	2.58	350
17	Cl	Chlorine	the Greek chloros, 'greenish yellow'	17	3	35.45[III][IV][V][VI]	0.003214	171.6	239.11	0.479	3.16	145
18	Ar	Argon	the Greek argos, 'idle'	18	3	39.948(1)[III][V]	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)[III]	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 a mischievous sprite of German miner mythology, Nickel	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)[V]	8.96	1357.77	2835	0.385	1.9	60
30	Zn	Zinc	German word Zinke (prong, tooth)	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 [IX]	887	0.329	2.18	1.8
34	Se	Selenium	the Greek selene, 'moon'	16	4	78.971(8)[V]	4.809	453	958	0.321	2.55	0.05
35	Br	Bromine	the Greek bromos, 'stench'	17	4	79.904[VI]	3.122	265.8	332.0	0.474	2.96	2.4
36	Kr	Krypton	the Greek kryptos, 'hidden'	18	4	83.798(2)[III][IV]	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)[III]	1.532	312.46	961	0.363	0.82	90
38	Sr	Strontium	Strontian, a small town in Scotland	2	5	87.62(1)[III][V]	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)[III]	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)[III]	10.22	2896	4912	0.251	2.16	1.2
43	Tc	Technetium	the Greek tekhnètos meaning 'artificial'	7	5	[98][X]	11.5	2430	4538	–	1.9	~ 3×10−9[XI]
44	Ru	Ruthenium	Ruthenia, the New Latin name for Russia	8	5	101.07(2)[III]	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)[III]	12.02	1828.05	3236	0.244	2.2	0.015
47	Ag	Silver	English word (argentum in Latin)	11	5	107.8682(2)[III]	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)[III]	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)[III]	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)[III]	6.685	903.78	1860	0.207	2.05	0.2
52	Te	Tellurium	Latin tellus, 'earth'	16	5	127.60(3)[III]	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)[III][IV]	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)[III]	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)[III]	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)[III]	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][X]	7.26	1315	3273	–	1.13	2×10−19[XI]
62	Sm	Samarium	Samarskite, the name of the mineral from which it was first isolated		6	150.36(2)[III]	7.52	1345	2067	0.197	1.17	7.05
63	Eu	Europium	Europe		6	151.964(1)[III]	5.243	1099	1802	0.182	1.2	2
64	Gd	Gadolinium	Johan Gadolin, chemist, physicist and mineralogist		6	157.25(3)[III]	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)[III]	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)[III]	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)[III]	6.965	1097	1469	0.155	1.1	3.2
71	Lu	Lutetium	Lutetia, the Latin name for Paris		6	174.9668(1)[III]	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)[III]	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[VI]	11.85	577	1746	0.129	1.62	0.85
82	Pb	Lead	English word (plumbum in Latin)	14	6	207.2(1)[III][V]	11.342	600.61	2022	0.129	1.87	14
83	Bi	Bismuth	Uncertain, possibly Arabic or German	15	6	208.98040(1)[X]	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][X]	9.32	527	1235	–	2.0	2×10−10[XI]
85	At	Astatine	the Greek astatos, 'unstable'	17	6	[210][X]	7	575	610	–	2.2	3×10−20[XI]
86	Rn	Radon	From radium, as it was first detected as an emission from radium during radioactive decay	18	6	[222][X]	0.00973	202	211.3	0.094	2.2	4×10−13[XI]
87	Fr	Francium	Francia, the New Latin name for France	1	7	[223][X]	1.87	300	950	–	0.7	~ 1×10−18[XI]
88	Ra	Radium	the Latin radius, 'ray'	2	7	[226][X]	5.5	973	2010	0.094	0.9	9×10−7[XI]
89	Ac	Actinium	the Greek aktis, 'ray'	3	7	[227][X]	10.07	1323	3471	0.12	1.1	5.5×10−10[XI]
90	Th	Thorium	Thor, the Scandinavian god of thunder		7	232.0377(4)[X][III]	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)[X]	15.37	1841	4300	–	1.5	1.4×10−6[XI]
92	U	Uranium	Uranus, the seventh planet in the Solar System		7	238.02891(3)[X]	18.95	1405.3	4404	0.116	1.38	2.7
93	Np	Neptunium	Neptune, the eighth planet in the Solar System		7	[237][X]	20.45	917	4273	–	1.36	≤ 3×10−12[XI]
94	Pu	Plutonium	Pluto, a dwarf planet in the Solar System (then considered the ninth planet)		7	[244][X]	19.84	912.5	3501	–	1.28	≤ 3×10−11[XI]
95	Am	Americium	The Americas, as the element was first synthesized on the continent, by analogy with europium		7	[243][X]	13.69	1449	2880	–	1.13	0[XII]
96	Cm	Curium	Pierre Curie, a physicist, and Marie Curie, a physicist and chemist, named after great scientists by analogy with gadolinium		7	[247][X]	13.51	1613	3383	–	1.28	0[XII]
97	Bk	Berkelium	Berkeley, California, where the element was first synthesized, by analogy with terbium		7	[247][X]	14.79	1259	2900	–	1.3	0[XII]
98	Cf	Californium	California, where the element was first synthesized		7	[251][X]	15.1	1173	(1743)[XIII]	–	1.3	0[XII]
99	Es	Einsteinium	Albert Einstein, physicist		7	[252][X]	8.84	1133	(1269)[XIII]	–	1.3	0[XII]
100	Fm	Fermium	Enrico Fermi, physicist		7	[257][X]	(9.7)[XIII]	(1125)[XIII]	–	–	1.3	0[XII]
101	Md	Mendelevium	Dmitri Mendeleev, chemist and inventor		7	[258][X]	(10.3)[XIII]	(1100)[XIII]	–	–	1.3	0[XII]
102	No	Nobelium	Alfred Nobel, chemist, engineer, innovator, and armaments manufacturer		7	[259][X]	(9.9)[XIII]	(1100)[XIII]	–	–	1.3	0[XII]
103	Lr	Lawrencium	Ernest O. Lawrence, physicist		7	[266][X]	(15.6)[XIII]	(1900)[XIII]	–	–	1.3	0[XII]
104	Rf	Rutherfordium	Ernest Rutherford, chemist and physicist	4	7	[267][X]	(23.2)[XIII]	(2400)[XIII]	(5800)[XIII]	–	–	0[XII]
105	Db	Dubnium	Dubna, Russia	5	7	[268][X]	(29.3)[XIII]	–	–	–	–	0[XII]
106	Sg	Seaborgium	Glenn T. Seaborg, scientist	6	7	[269][X]	(35.0)[XIII]	–	–	–	–	0[XII]
107	Bh	Bohrium	Niels Bohr, physicist	7	7	[270][X]	(37.1)[XIII]	–	–	–	–	0[XII]
108	Hs	Hassium	Hesse, Germany, where the element was first synthesized	8	7	[277][X]	(40.7)[XIII]	–	–	–	–	0[XII]
109	Mt	Meitnerium	Lise Meitner, physicist	9	7	[278][X]	(37.4)[XIII]	–	–	–	–	0[XII]
110	Ds	Darmstadtium	Darmstadt, Germany, where the element was first synthesized	10	7	[281][X]	(34.8)[XIII]	–	–	–	–	0[XII]
111	Rg	Roentgenium	Wilhelm Conrad Röntgen, physicist	11	7	[282][X]	(28.7)[XIII]	–	–	–	–	0[XII]
112	Cn	Copernicium	Nicolaus Copernicus, astronomer	12	7	[285][X]	(23.7)[XIII]	–	~357[XIV]	–	–	0[XII]
113	Nh	Nihonium	the Japanese name for Japan, Nihon, where the element was first synthesized	13	7	[286][X]	(16)[XIII]	(700)[XIII]	(1400)[XIII]	–	–	0[XII]
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][X]	(14)[XIII]	–	~210	–	–	0[XII]
115	Mc	Moscovium	Moscow Oblast, Russia, where the element was first synthesized	15	7	[290][X]	(13.5)[XIII]	(700)[XIII]	(1400)[XIII]	–	–	0[XII]
116	Lv	Livermorium	Lawrence Livermore National Laboratory (in Livermore, California) which collaborated with JINR on its synthesis	16	7	[293][X]	(12.9)[XIII]	(709)[XIII]	(1085)[XIII]	–	–	0[XII]
117	Ts	Tennessine	Tennessee, United States	17	7	[294][X]	(7.2)[XIII]	(723)[XIII]	(883)[XIII]	–	–	0[XII]
118	Og	Oganesson	Yuri Oganessian, physicist	18	7	[294][X]	(5.0)[XIII][XV]	–	(350)[XIII]	–	–	0[XII]

Notes

Background color shows subcategory in the metal–metalloid–nonmetal trend:

Metal						Metalloid	Nonmetal			Unknown chemical properties
Alkali metal	Alkaline earth metal	Lan­thanide	Actinide	Transition metal	Post-​transition metal		Polyatomic nonmetal	Diatomic nonmetal	Noble gas

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 symbol	Name	Atomic number	Origin of symbol	Why not used	Refs
A	Argon	18	A used for Argon until 1957. Current symbol is Ar.	[nb 2]	[6]
Ab	Alabamine	85	Discredited claim to discovery of astatine.	[nb 3]	[7]
Ad	Aldebaranium	70	Former name for ytterbium.	[nb 3]
Am	Alabamium	85	Discredited claim to discovery of astatine. The symbol is now used for americium.	[nb 3]	[7]
An	Athenium	99	Proposed name for einsteinium.	[nb 4]
Ao	Ausonium	93	Discredited claim to discovery of neptunium.	[nb 3]	[7]
Az	Azote	7	Former name for nitrogen.	[nb 2]
Bo	Boron	5	Current symbol is B.	[nb 2]
Bv	Brevium	91	Former name for protactinium.	[nb 2]
Bz	Berzelium		Baskerville wrongly believed berzelium to be a new element. Was actually thorium.	[nb 4]	[8]
Cb	Columbium	41	Former name for niobium.	[nb 2]	[7][8]
Ch	Chromium	24	Current symbol is Cr.	[nb 2]
Cl	Columbium	41	Former name for niobium. The symbol is now used for chlorine.	[nb 2]
Cn	Carolinium		Baskerville wrongly believed carolinium to be a new element. Was actually thorium. The symbol is now used for copernicium.		[8]
Cp	Cassiopeium	71	Former name for lutetium.	[nb 2]
Cp	Copernicium	112	Current symbol is Cn.	[nb 2]
Ct	Celtium	72	Discredited claim to discovery of hafnium.	[nb 3]
Ct	Centurium	100	Proposed name for fermium.	[nb 4]
D	Didymium		Mixture of the elements praseodymium and neodymium. Mosander wrongly believed didymium to be an element.		[9]
Da	Davyum	43	Discredited claim to discovery of technetium.	[nb 3]	[7]
Db	Dubnium	104	Proposed name for rutherfordium. The symbol and name were instead used for element 105.	[nb 2][nb 4]	[7]
Di	Didymium		Mixture of the elements praseodymium and neodymium. Mosander wrongly believed didymium to be an element.		[9]
Ds	Dysprosium	66	Current symbol is Dy. The symbol is now used for darmstadtium.	[nb 2]
E	Einsteinium	99	Current symbol is Es.	[nb 2]
E	Erbium	68	Current symbol is Er.	[nb 2]
Ea	Ekaaluminium	31	Name given by Mendeleev to an as of then undiscovered element. When discovered, gallium closely matched the prediction.	[nb 4][nb 5]
Eb	Ekaboron	21	Name given by Mendeleev to an as of then undiscovered element. When discovered, scandium closely matched the prediction.	[nb 4][nb 5]	[7]
El	Ekaaluminium	31	Name given by Mendeleev to an as of then undiscovered element. When discovered, gallium closely matched the prediction.	[nb 4][nb 5]	[7]
Em	Ekamanganese	43	Name given by Mendeleev to an as of then undiscovered element. When discovered, technetium closely matched the prediction.	[nb 4][nb 5]	[7]
Em	Emanation	86	Also 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]
Em	Emanium	89	Alternate name formerly proposed for actinium.	[nb 4]
Es	Ekasilicon	32	Name 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]
Es	Esperium	94	Discredited claim to discovery of plutonium. The symbol is now used for einsteinium.	[nb 3]	[7]
Fa	Francium	87	Current symbol is Fr.	[nb 2]
Fl	Florentium	61	Discredited claim to discovery of promethium. The symbol is now used for flerovium.	[nb 3]
Fl	Fluorine	9	Current symbol is F. The symbol is now used for flerovium.	[nb 2]
Fr	Florentium	61	Discredited claim to discovery of promethium. The symbol is now used for francium.	[nb 3]	[7]
G	Glucinium	4	Former name for beryllium.	[nb 2]
Gl	Glucinium	4	Former name for beryllium.	[nb 2]	[7]
Ha	Hahnium	105	Proposed name for dubnium.	[nb 4]
Hn	Hahnium	108	Proposed name for hassium.	[nb 4]	[7]
Hv	Helvetium	85	Discredited claim to discovery of astatine.	[nb 3]	[8]
Hy	Mercury	80	Hy from the Greek hydrargyrum for "liquid silver". Current symbol is Hg.	[nb 2]	[6]
I	Iridium	77	Current symbol is Ir. The symbol is now used for iodine.	[nb 2]
Il	Illinium	61	Discredited claim to discovery of promethium.	[nb 3]	[7]
J	Jodium	53	Former name for iodine.	[nb 2]
Jg	Jargonium	72	Discredited claim to discovery of hafnium.	[nb 3]	[7]
Jl	Joliotium	105	Proposed name for dubnium.	[nb 4]	[7]
Ka	Potassium	19	Current symbol is K.	[nb 2]
Ku	Kurchatovium	104	Proposed name for rutherfordium.	[nb 4]	[7]
L	Lithium	3	Current symbol is Li.	[nb 2]
Lw	Lawrencium	103	Current symbol is Lr.	[nb 2]
M	Muriaticum	17	Former name for chlorine.	[nb 2]
Ma	Manganese	25	Current symbol is Mn.	[nb 2]
Ma	Masurium	43	Disputed claim to discovery of technetium.	[nb 3]	[7]
Md	Mendelevium	97	Proposed name for berkelium. The symbol and name were later used for element 101.	[nb 2][nb 4]
Ml	Moldavium	87	Discredited claim to discovery of francium.	[nb 3]	[8]
Ms	Magnesium	12	Current symbol is Mg.	[nb 2]
Ms	Masrium	88	Discredited claim of discovery of radium.	[nb 3]
Ms	Masurium	43	Disputed claim to discovery of technetium.	[nb 3]
Mv	Mendelevium	101	Current symbol is Md.	[nb 2]
Ng	Norwegium	72	Discredited claim to discovery of hafnium.	[nb 3]
No	Norium	72	Discredited claim to discovery of hafnium. The symbol is now used for nobelium.	[nb 3]
Np	Nipponium	43	Discredited claim to discovery of technetium. The symbol is now used for neptunium.	[nb 3]	[7]
Ns	Nielsbohrium	105	Proposed name for dubnium.	[nb 4]	[7]
Ns	Nielsbohrium	107	Proposed name for bohrium.	[nb 4]	[7]
Nt	Niton	86	Former name for radon.	[nb 2]	[7]
Ny	Neoytterbium	70	Former name for ytterbium.	[nb 2]
P	Lead	82	Current symbol is Pb. The symbol is now used for phosphorus.	[nb 2]
Pa	Palladium	46	Current symbol is Pd. The symbol is now used for protactinium.	[nb 2]
Pe	Pelopium	41	Former name for niobium.	[nb 2]
Pl	Palladium	46	Current symbol is Pd.	[nb 2]
Po	Potassium	19	Current symbol is K. The symbol is now used for polonium.	[nb 2]
R	Rhodium	45	Current symbol is Rh.	[nb 2]
Rd	Radium	88	Current symbol is Ra.	[nb 2]
Rf	Rutherfordium	106	Proposed name for seaborgium. The symbol and name were instead used for element 104.	[nb 2][nb 4]	[7]
Ro	Rhodium	45	Current symbol is Rh.	[nb 2]
Sa	Samarium	62	Current symbol is Sm.	[nb 2]	[7]
So	Sodium	11	Current symbol is Na.	[nb 2]
St	Antimony	51	Current symbol is Sb.	[nb 2]
St	Tin	50	Current symbol is Sn.	[nb 2]
Tn	Tungsten	74	Current symbol is W.	[nb 2]
Tr	Terbium	65	Current symbol is Tb.	[nb 2]
Tu	Thulium	69	Current symbol is Tm.	[nb 2]
Tu	Tungsten	74	Current symbol is W.	[nb 2]
Unb	Unnilbium	102	Temporary name given to nobelium until it was permanently named by IUPAC.	[nb 5]
Une	Unnilennium	109	Temporary name given to meitnerium until it was permanently named by IUPAC.	[nb 5]
Unh	Unnilhexium	106	Temporary name given to seaborgium until it was permanently named by IUPAC.	[nb 5]
Uno	Unniloctium	108	Temporary name given to hassium until it was permanently named by IUPAC.	[nb 5]
Unp	Unnilpentium	105	Temporary name given to dubnium until it was permanently named by IUPAC.	[nb 5]
Unq	Unnilquadium	104	Temporary name given to rutherfordium until it was permanently named by IUPAC.	[nb 5]
Uns	Unnilseptium	107	Temporary name given to bohrium until it was permanently named by IUPAC.	[nb 5]
Unt	Unniltrium	103	Temporary name given to lawrencium until it was permanently named by IUPAC.	[nb 5]
Unu	Unnilunium	101	Temporary name given to mendelevium until it was permanently named by IUPAC.	[nb 5]
Uub	Ununbium	112	Temporary name given to copernicium until it was permanently named by IUPAC.	[nb 5]
Uuh	Ununhexium	116	Temporary name given to livermorium until it was permanently named by IUPAC.	[nb 5]
Uun	Ununnilium	110	Temporary name given to darmstadtium until it was permanently named by IUPAC.	[nb 5]
Uuo	Ununoctium	118	Temporary name given to oganesson until it was permanently named by IUPAC.	[nb 5]
Uup	Ununpentium	115	Temporary name given to moscovium until it was permanently named by IUPAC.	[nb 5]
Uuq	Ununquadium	114	Temporary name given to flerovium until it was permanently named by IUPAC.	[nb 5]
Uus	Ununseptium	117	Temporary name given to tennessine until it was permanently named by IUPAC.	[nb 5]
Uut	Ununtrium	113	Temporary name given to nihonium until it was permanently named by IUPAC.	[nb 5]
Uuu	Unununium	111	Temporary name given to roentgenium until it was permanently named by IUPAC.	[nb 5]
Ur	Uranium	92	Current symbol is U.	[nb 2]
Vi	Virginium	87	Discredited claim to discovery of francium.	[nb 3]	[7]
Vm	Virginium	87	Discredited claim to discovery of francium.	[nb 3]	[7]
Va	Vanadium	23	Current symbol is V.	[nb 2]
Wo	Tungsten	74	Current symbol is W.	[nb 2]
X	Xenon	54	Current symbol is Xe.	[nb 2]
Yt	Yttrium	39	Current 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 symbol	Original name	Modern name	Atomic number	Origin of symbol
☉	Hydrogen	Hydrogen	1	Daltonian symbol circa 1808.
⬤	Carbon	Carbon	6	Daltonian symbol circa 1808.
⦶	Azote	Nitrogen	7	Daltonian symbol circa 1808.
◯	Oxygen	Oxygen	8	Daltonian symbol circa 1808.
⦷	Soda	Sodium	11	Daltonian symbol circa 1808.
⊛	Magnesium	Magnesium	12	Alchemical symbol.
	Sulfur	Sulfur	16	Alchemical symbol.
	Pallas	Sulfur	16	Alchemical symbol.
🜍	Sulfur	Sulfur	16	Alchemical symbol.
ⴲ	Sulfur	Sulfur	16	Daltonian symbol circa 1808.
♂	Mars	Iron	26	Alchemical symbol.
Ⓘ	Iron	Iron	26	Daltonian symbol circa 1808.
	Stellae Fixae	Copper	29	Pre–16th-century alchemical symbol.
♀	Venus	Copper	29	Alchemical symbol.
	Copper	Copper	29	Alchemical symbol.
Ⓒ	Copper	Copper	29	Daltonian symbol circa 1808.
Ⓩ	Zinc	Zinc	30	Daltonian symbol circa 1808.
	Arsenic	Arsenic	33	Alchemical symbol.
🜺	Arsenic	Arsenic	33	Alchemical symbol.
☽	Luna	Silver	47	Alchemical symbol.
🜛	Silver	Silver	47	Alchemical symbol.
Ⓢ	Silver	Silver	47	Daltonian symbol circa 1808.
♃	Iupiter	Tin	50	Alchemical symbol.
♁	Antimony	Antimony	51	Alchemical symbol.
☉☾	Platinum	Platinum	78	Alchemical symbol.
⛢	Uranus	Platinum	78	Alchemical symbol.
☼	Sol	Gold	79	Alchemical symbol from the 16th century.
☉	Sol	Gold	79	Alchemical symbol from 1700 through 1783.
🜚	Gold	Gold	79	Alchemical symbol.
♓	Pisces	Mercury	80	Pre–16th-century alchemical symbol.
♆	Neptunus	Mercury	80	Alchemical symbol from the 17th century.
☿	Mercurius	Mercury	80	Alchemical symbol from 1700 through 1783.
♄	Saturnus	Lead	82	Alchemical symbol circa 1783.
Ⓛ	Lead	Lead	82	Daltonian symbol circa 1808.
♉	Taurus	Bismuth	83	Alchemical 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, as is thoron (Tn) for radon-220 (though not actinon; An is usually used instead for a generic actinide). 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 and radon 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 symbol	Name	Atomic number	Origin of symbol
Ac	Actinium	89	From 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.
AcA	Actinium A	84	From actinium and A. Placeholder name given at one time to 215Po, an isotope of polonium identified in the decay chain of actinium.
AcB	Actinium B	82	From actinium and B. Placeholder name given at one time to 211Pb, an isotope of lead identified in the decay chain of actinium.
AcC	Actinium C	83	From 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'	84	From 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"	81	From actinium and C". Placeholder name given at one time to 207Tl, an isotope of thallium identified in the decay chain of actinium.
AcK	Actinium K	87	Name given at one time to 223Fr, an isotope of francium identified in the decay chain of actinium.
AcU	Actino-uranium	92	Name given at one time to 235U, an isotope of uranium.
AcX	Actinium X	88	Name given at one time to 223Ra, an isotope of radium identified in the decay chain of actinium.
An	Actinon	86	From actinium and emanation. Name given at one time to 219Rn, an isotope of radon identified in the decay chain of actinium.
D	Deuterium	1	From the Greek deuteros. Name given to 2H.
Io	Ionium	90	Name given to 230Th, an isotope of thorium identified in the decay chain of uranium.
MsTh1	Mesothorium 1	88	Name given at one time to 228Ra, an isotope of radium.
MsTh2	Mesothorium 2	89	Name given at one time to 228Ac, an isotope of actinium.
Pa	Protactinium	91	From 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.
Ra	Radium	88	From 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.
RaA	Radium A	84	From radium and A. Placeholder name given at one time to 218Po, an isotope of polonium identified in the decay chain of radium.
RaB	Radium B	82	From radium and B. Placeholder name given at one time to 214Pb, an isotope of lead identified in the decay chain of radium.
RaC	Radium C	83	From 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'	84	From 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"	81	From radium and C". Placeholder name given at one time to 210Tl, an isotope of thallium identified in the decay chain of radium.
RaD	Radium D	82	From radium and D. Placeholder name given at one time to 210Pb, an isotope of lead identified in the decay chain of radium.
RaE	Radium E	83	From 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"	81	From radium and E". Placeholder name given at one time to 206Tl, an isotope of thallium identified in the decay chain of radium.
RaF	Radium F	84	From radium and F. Placeholder name given at one time to 210Po, an isotope of polonium identified in the decay chain of radium.
RdAc	Radioactinium	90	Name given at one time to 227Th, an isotope of thorium.
RdTh	Radiothorium	90	Name given at one time to 228Th, an isotope of thorium.
Rn	Radon	86	From 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.
T	Tritium	1	From the Greek tritos. Name given to 3H.
Th	Thorium	90	After Thor. Name restricted at one time to 232Th, an isotope of thorium. This named isotope later became the official name for element 90.
ThA	Thorium A	84	From thorium and A. Placeholder name given at one time to 216Po, an isotope of polonium identified in the decay chain of thorium.
ThB	Thorium B	82	From thorium and B. Placeholder name given at one time to 212Pb, an isotope of lead identified in the decay chain of thorium.
ThC	Thorium C	83	From 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'	84	From 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"	81	From thorium and C". Placeholder name given at one time to 208Tl, an isotope of thallium identified in the decay chain of thorium.
ThX	Thorium X	88	Name given at one time to 224Ra, an isotope of radium identified in the decay chain of thorium.
Tn	Thoron	86	From thorium and emanation. Name given at one time to 220Rn, an isotope of radon identified in the decay chain of thorium.
UI	Uranium I	92	Name given at one time to 238U, an isotope of uranium.
UII	Uranium II	92	Name given at one time to 234U, an isotope of uranium.
UX1	Uranium X1	90	Name given at one time to 234Th, an isotope of thorium identified in the decay chain of uranium.
UX2	Uranium X2	91	Name given at one time to 234mPa, an isotope of protactinium identified in the decay chain of uranium.
UY	Uranium Y	90	Name given at one time to 231Th, an isotope of thorium identified in the decay chain of uranium.
UZ	Uranium Z	91	Name 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:

• An: any actinide
• E: any element or electrophile
• L: any ligand
• Ln: any lanthanide
• M: any metal
• Mm: mischmetall (occasionally used)^[12]
• Ng: any noble gas (Rg is sometimes used, but that is also used for the element roentgenium: see above)
• Nu: any nucleophile
• R: any unspecified radical (moiety) not important to the discussion
• St: steel (occasionally used)
• X: any halogen

From organic chemistry:

• Ac: acetyl – (also used for the element actinium: see above)
• Ad: adamantyl
• Ar: aryl – (also used for the element argon: see above)
• Bn: benzyl
• Bu: butyl
• Bz: benzoyl
• Cp: cyclopentadienyl
• Cy: cyclohexyl
• Et: ethyl
• i-Pr, ⁱPr, Prⁱ: isopropyl
• Me: methyl
• Mes: mesityl (2,3,6-trimethylphenyl)
• Ms: mesyl (methylsulfonyl)
• Np: neopentyl – (also used for the element neptunium: see above)
• Ph: phenyl
• Pr: propyl – (also used for the element praseodymium: see above)
• s-Bu: sec-butyl
• R: In organic chemistry contexts, an unspecified "R" is often understood to be an alkyl group
• t-Bu: tert-butyl
• Tf: triflyl (trifluoromethanesulfonyl)
• Tr: trityl (triphenylmethyl)
• Ts (occasionally Tos): tosyl (para toluenesulfonyl) – (also used for the element tennessine: see above)

Exotic atoms:

• Mu: muonium
• Pn: protonium
• Ps: positronium

See also

• List of chemical elements naming controversies
• List of elements
• Nuclear notation

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.

Name changed due to a standardization of, modernization of, or update to older formerly-used symbol.

Name designated by discredited/disputed claimant.

Name proposed prior to discovery/creation of element or prior to official re-naming of a placeholder name.

5. Temporary placeholder name.

References

1. 
   

"Periodic Table – Royal Society of Chemistry". www.rsc.org.

"Online Etymology Dictionary". etymonline.com.

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)

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)

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. JSTOR 20020628.

Holden, N. E. (12 March 2004). "History of the Origin of the Chemical Elements and Their Discoverers". National Nuclear Data Center.

Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19: 175–183. doi:10.1007/s10699-013-9326-y.

Fontani, Marco; Costa, Mariagrazia; Orna, Mary Virginia (2014). The Lost Elements: The Periodic Table's Shadow Side. Oxford University Press. ISBN 9780199383344.

Praseodymium. was.chemistryexplained.com.

IUPAC. "Isotopically Modified Compounds". IUPAC. Retrieved 31 March 2015.

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.

• Element name etymologies. Retrieved July 15, 2005.
• Atomic Weights of the Elements 2001, Pure Appl. Chem. 75(8), 1107–1122, 2003. Retrieved June 30, 2005. Atomic weights of elements with atomic numbers from 1–109 taken from this source.
• IUPAC Standard Atomic Weights Revised (2005).
• WebElements Periodic Table. Retrieved June 30, 2005. Atomic weights of elements with atomic numbers 110–116 taken from this source.
• Lapp, Ralph E. Matter. Life Science Library. New York: Time, Inc. 1963.
• Leighton, Robert B. Principles of Modern Physics. New York: McGraw-Hill. 1959.
• Scerri, E.R. "The Periodic Table, Its Story and Its Significance". New York, Oxford University Press. 2007.

External links

Wikimedia Commons has media related to Symbol (chemistry).

• Berzelius' List of Elements
• History of IUPAC Atomic Weight Values (1883 to 1997)
• American Chemical Society, Committee on Nomenclature, Terminology & Symbols

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