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List of elements by symbol

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1 Current symbols
2 Symbols not currently used
- 2.1 Pictographic symbols
3 Symbols for named isotopes
4 Other symbols that look like element symbols
5 Notes
6 References

This is a list of chemical elements by symbol, including the current signification used to identify the chemical elements as recognized by the International Union of Pure and Applied Chemistry, as well as proposed and historical signs. Also given is each element's atomic number, atomic mass or most stable isotope, group and period numbers on the periodic table, and etymology of the symbol.

NOTE: placing one's cursor over the entry in the etymology column will display a modern English translation for words of Greek, Latin, or other origin.

Element categories in the periodic table

Metals						Metalloids	Nonmetals
Alkali metals	Alkaline earth metals	Inner transition elements		Transition elements	Other metals		Other nonmetals	Halogens	Noble gases
		Lanthanides	Actinides

Current symbols

Symbol	Name	Etymology of Symbol	Atomic Number	Relative Atomic Mass	Group	Period
Ac	Actinium	corruption of the Greek aktinos	89	[227]^[1]		7
Ag	Silver	Latin argentum	47	107.8682(2)^[2]	11	5
Al	Aluminium (Aluminum)	Latin alumen	13	26.9815386(8)	13	3
Am	Americium	the Americas	95	[243]^[1]		7
Ar	Argon	Greek argon	18	39.948(1)^[2] ^[3]	18	3
As	Arsenic	Greek arsenikos	33	74.92160(2)	15	4
At	Astatine	Greek astatos	85	[210]^[1]	17	6
Au	Gold	Latin aurum	79	196.966569(4)	11	6
B	Boron	borax	5	10.811(7)^[2] ^[4] ^[3]	13	2
Ba	Barium	Greek barys	56	137.327(7)	2	6
Be	Beryllium	beryl	4	9.012182(3)	2	2
Bh	Bohrium	Neils Bohr	107	[264]^[1]	7	7
Bi	Bismuth	corruption of the German wissmuth	83	208.98040(1)	15	6
Bk	Berkelium	Berkeley, California	97	[247]^[1]		7
Br	Bromine	Greek bromos	35	79.904(1)	17	4
C	Carbon	Latin carbo	6	12.0107(8)^[2] ^[3]	14	2
Ca	Calcium	Latin calx	20	40.078(4)^[2]	2	4
Cd	Cadmium	corruption of the Greek kadmia	48	112.411(8)^[2]	12	5
Ce	Cerium	Ceres	58	140.116(1)^[2]		6
Cf	Californium	State and University of California	98	[251]^[1]		7
Cl	Chlorine	Greek chloros	17	35.453(2)^[2] ^[4] ^[3]	17	3
Cm	Curium	Pierre and Marie Curie and the traditional -um ending	96	[247]^[1]		7
Co	Cobalt	corruption of the German kobold	27	58.933195(5)	9	4
Cr	Chromium	Greek chroma	24	51.9961(6)	6	4
Cs	Caesium (Cesium)	Latin caesius	55	132.9054519(2)	1	6
Cu	Copper	Latin Cuprum	29	63.546(3)^[3]	11	4
Db	Dubnium	Dubna, Russia	105	[262]^[1]	5	7
Ds	Darmstadtium	Darmstadt, Germany	110	[271]^[1]	10	7
Dy	Dysprosium	Greek dysprositos	66	162.500(1)^[2]		6
Er	Erbium	Ytterby, Sweden	68	167.259(3)^[2]		6
Es	Einsteinium	Albert Einstein	99	[252]^[1]		7
Eu	Europium	Europe	63	151.964(1)^[2]		6
F	Fluorine	Latin fluo	9	18.9984032(5)	17	2
Fe	Iron	Latin ferrum	26	55.845(2)	8	4
Fm	Fermium	Enrico Fermi	100	[257]^[1]		7
Fr	Francium	France	87	[223]^[1]	1	7
Ga	Gallium	Latin Gallia	31	69.723(1)	13	4
Gd	Gadolinium	gadolinite	64	157.25(3)^[2]		6
Ge	Germanium	Germany	32	72.64(1)	14	4
H	Hydrogen	Greek hydror	1	1.00794(7)^[2] ^[4] ^[3]	1	1
He	Helium	Greek helios	2	4.002602(2)^[2] ^[3]	18	1
Hf	Hafnium	Latin Hafnia	72	178.49(2)	4	6
Hg	Mercury	Latin hydrargyrum	80	200.59(2)	12	6
Ho	Holmium	Latin Holmia	67	164.930 32(2)		6
Hs	Hassium	Hesse, Germany	108	[277]^[1]	8	7
I	Iodine	Greek ioeides	53	126.904 47(3)	17	5
In	Indium	indigo blue	49	114.818(3)	13	5
Ir	Iridium	Greek iris	77	192.217(3)	9	6
K	Potassium (Kalium)	Latin kalium	19	39.0983(1)	1	4
Kr	Krypton	Greek kryptos	36	83.798(2)^[2] ^[4]	18	4
La	Lanthanum	Greek lanthanien	57	138.90547(7)^[2]		6
Li	Lithium	Greek lithos	3	6.941(2)^[2] ^[4] ^[3] ^[5]	1	2
Lr	Lawrencium	Ernest O. Lawrence	103	[262]^[1]	3	7
Lu	Lutetium	Latin Lutetia	71	174.967(1)^[2]	3	6
Md	Mendelevium	Dmitri Mendeleyev	101	[258]^[1]		7
Mg	Magnesium	Magnesia, Greece	12	24.3050(6)	2	3
Mn	Manganese	Latin magnes	25	54.938045(5)	7	4
Mo	Molybdenum	Greek molybdos	42	95.94(2)^[2]	6	5
Mt	Meitnerium	Lise Meitner	109	[268]^[1]	9	7
N	Nitrogen	Greek nitron	7	14.0067(2)^[2] ^[3]	15	2
Na	Sodium	Latin natrium	11	22.98976928(2)	1	3
Nb	Niobium	Niobe	41	92.906 38(2)	5	5
Nd	Neodymium	Greek neos didymos	60	144.242(3)^[2]		6
Ne	Neon	Greek neos	10	20.1797(6)^[2] ^[4]	18	2
Ni	Nickel	German kupfernickel	28	58.6934(2)	10	4
No	Nobelium	Alfred Nobel	102	[259]^[1]		7
Np	Neptunium	Neptune	93	[237]^[1]		7
O	Oxygen	Greek oxys	8	15.9994(3)^[2] ^[3]	16	2
Os	Osmium	Greek osme	76	190.23(3)^[2]	8	6
P	Phosphorus	Greek phosphoros	15	30.973762(2)	15	3
Pa	Protactinium	Greek protos and actinium	91	231.03588(2)^[1]		7
Pb	Lead	Latin plumbum	82	207.2(1)^[2] ^[3]	14	6
Pd	Palladium	Pallas and the traditional -dium ending	46	106.42(1)^[2]	10	5
Pm	Promethium	Prometheus	61	[145]^[1]		6
Po	Polonium	Poland	84	[210]^[1]	16	6
Pr	Praseodymium	Greek prasios	59	140.90765(2)		6
Pt	Platinum	Greek platina	78	195.084(9)	10	6
Pu	Plutonium	Pluto	94	[244]^[1]		7
Ra	Radium	Latin radius	88	[226]^[1]	2	7
Rb	Rubidium	Latin rubidus	37	85.4678(3)^[2]	1	5
Re	Rhenium	German Rheinprovinz	75	186.207(1)	7	6
Rf	Rutherfordium	Ernest Rutherford	104	261^[1]	4	7
Rg	Roentgenium	Wilhelm Conrad Röntgen	111	[272]^[1]	11	7
Rh	Rhodium	Greek rhodon	45	102.905 50(2)	9	5
Rn	Radon	radium and emanation	86	[220]^[1]	18	6
Ru	Ruthenium	Latin Ruthenia	44	101.07(2)^[2]	8	5
S	Sulfur (Sulphur)	Latin sulfur	16	32.065(5)^[2] ^[3]	16	3
Sb	Antimony	Latin stibium	51	121.760(1)^[2]	15	5
Sc	Scandium	Scandinavia	21	44.955912(6)	3	4
Se	Selenium	Greek selene	34	78.96(3)^[3]	16	4
Sg	Seaborgium	Glenn T. Seaborg	106	[266]^[1]	6	7
Si	Silicon	Latin silex	14	28.0855(3)^[3]	14	3
Sm	Samarium	samarskite	62	150.36(2)^[2]		6
Sn	Tin	Latin stannum	50	118.710(7)^[2]	14	5
Sr	Strontium	Latin Strontian	38	87.62(1)^[2] ^[3]	2	5
Ta	Tantalum	King Tantalus	73	180.94788(2)	5	6
Tb	Terbium	Ytterby, Sweden	65	158.92535(2)		6
Tc	Technetium	Greek technetos	43	[98]^[1]	7	5
Te	Tellurium	Greek tellus	52	127.60(3)^[2]	16	5
Th	Thorium	Thor	90	232.03806(2)^[1] ^[2]		7
Ti	Titanium	the Titans	22	47.867(1)	4	4
Tl	Thallium	Greek thallos	81	204.3833(2)	13	6
Tm	Thulium	Thule and the traditional -ium ending	69	168.93421(2)		6
U	Uranium	Uranus	92	238.02891(3)^[1] ^[2] ^[4]		7
Uub	Ununbium	Latin uni, uni, and bi	112	[285]^[1]	12	7
Uuh	Ununhexium	Latin uni, uni, and Greek hex	116	[292]^[1]	16	7
Uuo	Ununoctium	Latin uni, uni, and oct	118	[294]^[1]	18	7
Uup	Ununpentium	Latin uni, uni, and Greek pent	115	[288]^[1]	15	7
Uuq	Ununquadium	Latin uni, uni, and quadr	114	[289]^[1]	14	7
Uut	Ununtrium	Latin uni, uni, and Greek tri	113	[284]^[1]	13	7
V	Vanadium	Vanadis	23	50.9415(1)	5	4
W	Tungsten	German wolfram	74	183.84(1)	6	6
Xe	Xenon	Greek xenos	54	131.293(6)^[2] ^[4]	18	5
Y	Yttrium	Ytterby, Sweden	39	88.90585(2)	3	5
Yb	Ytterbium	Ytterby, Sweden	70	173.04(3)^[2]		6
Zn	Zinc	German zin	30	65.409(4)	12	4
Zr	Zirconium	zircon	40	91.224(2)^[2]	4	5

Element categories in the periodic table

Metals						Metalloids	Nonmetals
Alkali metals	Alkaline earth metals	Inner transition elements		Transition elements	Other metals		Other nonmetals	Halogens	Noble gases
		Lanthanides	Actinides

Symbols not currently used

The following is a list of names formerly used or suggested for use in naming the elements listed above. Also included in this list are placeholder names and names given by discredited claimants for discovery. Names which retain local use (as with aluminum and jod) are not included in this table.

Chemical Symbol	Name	Atomic Number	Origin of Symbol	Why Not Used
A	Argon	18	Current symbol is Ar.	^[6]
Ab	Alabamine	85	Discredited claim to discovery of astatine.	^[7]
Am	Alabamium	85	Discredited claim to discovery of astatine.	^[7]
An	Athenium	99	Proposed name for einsteinium.	^[8]
Ao	Ausonium	93	Discredited claim to discovery of neptunium.	^[7]
Az	Azote	7	Former name for nitrogen.	^[6]
Bv	Brevium	91	Former name for protactinium.	^[6]
Bz	Berzelium	59	Suggested name for praseodymium.	^[8]
Cb	Columbium	41	Former name of niobium.	^[6]
Cb	Columbium	95	Suggested name for americium.	^[8]
Cp	Cassiopeium	71	Former name for lutetium.	^[6]
Ct	Centurium	100	Proposed name for fermium.	^[8]
Ct	Celtium	72	Former name of hafnium.	^[6]
Da	Danubium	43	Suggested name for technetium.	^[8]
Db	Dubnium	104	Proposed name for rutherfordium. The symbol and name were used for element 105.	^[6] ^[8]
Eb	Ekaboron	21	Name given by Mendeleev to an as of then undiscovered element. When discovered, scandium closely matched the prediction.	^[8] ^[9]
El	Ekaaluminium	31	Name given by Mendeleev to an as of then undiscovered element. When discovered, gallium closely matched the prediction.	^[8] ^[9]
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).	^[6]
Em	Ekamangan	43	Name given by Mendeleev to an as of then undiscovered element. When discovered, technetium closely matched the prediction.	^[8] ^[9]
Es	Ekasilicon	32	Name given by Mendeleev to an as of then undiscovered element. When discovered, germanium closely matched the prediction.	^[8] ^[9]
Es	Esperium	94	Discredited claim to discovery of plutonium.	^[7]
Fa	Francium	87	Current symbol is Fr.	^[6]
Fr	Florentium	61	Discredited claim to discovery of promethium.	^[7]
Gl	Glucinium	4	Former name of beryllium.	^[6]
Ha	Hahnium	105	Proposed name for dubnium.	^[8]
Ha	Hahnium	108	Proposed name for hassium.	^[8]
Il	Illinium	61	Discredited claim to discovery of promethium.	^[7]
Jg	Jargonium	72	Discredited claim to discovery of hafnium.	^[7]
Jo	Joliotium	105	Proposed name for dubnium.	^[8]
Ku	Kurchatovium	104	Proposed name for rutherfordium.	^[8]
Lw	Lawrencium	103	Current symbol is Lr.	^[6]
M	Muriaticum	17	Former name of chlorine.	^[6]
Ma	Masurium	43	Disputed claim to discovery of technetium.	^[7]
Md	Mendelevium	97	Proposed name for berkelium. The symbol and name were later used for element 101.	^[6] ^[8]
Me	Mendelevium	68	Suggested name for erbium.	^[6]
Ms	Masrium	49	Discredited claim of discovery of indium.	^[7]
Mt	Meitnium	91	Suggested name for protactinium.	^[8]
Mv	Mendelevium	101	Current symbol is Md.	^[6]
Ng	Norwegium	72	Discredited claim to discovery of hafnium.	^[7]
Ni	Niton	86	Former name for radon.	^[6]
No	Norium	72	Discredited claim to discovery of hafnium.	^[7]
Ns	Nielsbohrium	105	Proposed name for dubnium.	^[8]
Ns	Nielsbohrium	107	Proposed name for bohrium.	^[8]
Nt	Niton	86	Suggested name for radon.	^[8]
Ny	Neoytterbium	70	Former name of ytterbium.	^[6]
Od	Odinium	62	Suggested name for samarium.	^[8]
Pc	Policium	110	Proposed name for darmstadtium.	^[8]
Pe	Pelopium	41	Former name for niobium.	^[6]
Po	Potassium	19	Current symbol is K.	^[6]
Rf	Rutherfordium	106	Proposed name for seaborgium. The symbol and name were instead used for element 104.	^[6] ^[8]
Sa	Samarium	62	Current symbol is Sm.	^[6]
So	Sodium	11	Current symbol is Na.	^[6]
Sp	Spectrium	70	Suggested name for ytterbium.	^[8]
St	Antimony	51	Current symbol is Sb.	^[6]
Tn	Tungsten	74	Current symbol is W.	^[6]
Tu	Thulium	69	Current symbol is Tm.	^[6]
Tu	Tungsten	74	Current symbol is W.	^[6]
Ty	Tyrium	60	Suggested name for neodymium.	^[8]
Unb	Unnilbium	102	Temporary name given to nobelium until it was permanently named by IUPAC.	^[9]
Une	Unnilennium	109	Temporary name given to meitnerium until it was permanently named by IUPAC.	^[9]
Unh	Unnilhexium	106	Temporary name given to seaborgium until it was permanently named by IUPAC.	^[9]
Uno	Unniloctium	108	Temporary name given to hassium until it was permanently named by IUPAC.	^[9]
Unp	Unnilpentium	105	Temporary name given to dubnium until it was permanently named by IUPAC.	^[9]
Unq	Unnilquadium	104	Temporary name given to rutherfordium until it was permanently named by IUPAC.	^[9]
Uns	Unnilseptium	107	Temporary name given to bohrium until it was permanently named by IUPAC.	^[9]
Unt	Unniltrium	103	Temporary name given to lawrencium until it was permanently named by IUPAC.	^[9]
Unu	Unnilunium	101	Temporary name given to mendelevium until it was permanently named by IUPAC.	^[9]
Uun	Ununnilium	110	Temporary name given to darmstadtium until it was permanently named by IUPAC.	^[9]
Uuu	Unununium	111	Temporary name given to roentgenium until it was permanently named by IUPAC.	^[9]
Vi	Virginium	87	Discredited claim to discovery of francium.	^[7]
Vm	Virginium	87	Discredited claim to discovery of francium.	^[7]
Yt	Yttrium	39	Current symbol is Y.	^[6]

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 Traditional Chinese elements. Modern alphabetic notation was introduced in 1814 by Jöns Jakob Berzelius.

Chemical Symbol	Original Name	Modern Name	Atomic Number	Origin of Symbol	Why Not Used
	Hydrogen	Hydrogen	1	Daltonian symbol circa 1808.	^[6]
	Sulfur	Sulfur	16	Alchemical symbol.	^[6]
	Pallas	Sulfur	16	Alchemical symbol.	^[6]
	Sulfur	Sulfur	16	Daltonian symbol circa 1808.	^[6]
⊛	Magnesium	Magnesium	21	Alchemical symbol.	^[6]
♂	Mars	Iron	26	Alchemical symbol.	^[6]
	Stellae Fixae	Copper	29	Pre-1500s alchemical symbol.	^[6]
♀	Venus	Copper	29	Alchemical symbol.	^[6]
	Copper	Copper	29	Alchemical symbol.	^[6]
©	Copper	Copper	29	Daltonian symbol circa 1808.	^[6]
	Arsenic	Arsenic	33	Alchemical symbol.	^[6]
	Luna	Silver	47	Alchemical symbol.	^[6]
	Iupiter	Tin	50	Alchemical symbol.	^[6]
♁	Antimony	Antimony	51	Alchemical symbol.	^[6]
	Antimony	Antimony	51	Alchemical symbol.	^[6]
☾	Platinum	Platinum	78	Alchemical symbol.	^[6]
☉	Platinum	Platinum	78	Alchemical symbol.	^[6]
	Uranus	Platinum	78	Alchemical symbol.	^[6]
☼	Sol	Gold	79	Alchemical symbol from the 1500s	^[6]
	Sol	Gold	79	Alchemical symbol from 1700 through 1783.	^[6]
[1]	Pisces	Mercury	80	Pre-1500s alchemical symbol.	^[6]
	Neptunus	Mercury	80	Alchemical symbol from the 1600s.	^[6]
	Mercurius	Mercury	80	Alchemical symbol from 1700 through 1783.	^[6]
	Saturnus	Lead	82	Alchemical symbol circa 1783.	^[6]
	Taurus	Bismuth	83	Alchemical symbol.	^[6]

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj 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, three elements, Thorium, Protactinium, and Uranium, have a characteristic terrestrial isotopic composition, and thus their atomic mass given.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj ^ak ^al ^am The isotopic composition of this element varies in some geological specimens, and the variation may exceed the uncertainty stated in the table.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o The isotopic composition varies in terrestrial material such that a more precise atomic weight can not be given.
^ ^a ^b ^c ^d ^e ^f ^g ^h The isotopic composition of the element can vary in commercial materials, which can cause the atomic weight to deviate significantly from the given value.
^ 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.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj ^ak ^al ^am ^an ^ao ^ap ^aq ^ar ^as ^at ^au ^av ^aw ^ax ^ay ^az Name changed due to a standardization of, modernization of, or update to older previously used symbol.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Name designated by discredited/disputed claimant.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x Name proposed prior to discovery/creation of element or prior to official re-naming of a placeholder name.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o Temporary placeholder name.

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 Index to isotope pages chart. Some of the following symbols are no longer in use within the scientific community, however others (most notably some of the named isotopes of hydrogen) continue to be used today. 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. Although it is not an isotope, this is perhaps the most useful place to mention that H is the proposed symbol for the only created anti-element, antihydrogen.

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 at one time 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 ²³⁴Pa, 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 that look like element symbols

Ab: albite
Ac: acetate - (also used for the element actinium: see above)
Ar: aryl - (also used for the element argon: see above)
Bn: benzyl
Bu: butyl
Bz: benzoyl - (also used for berzelium, an old suggested name for praseodymium).
Di: didymium - Rare earth metal that proved to be a mixture of the elements praseodymium and neodymium.
Dp: decipium - Rare earth metal that proved to be a mixture of the elements samarium, neodymium and praseodymium.
Et: ethyl
M: metal - any metal atom
Me: methyl
Mu: muonium
Ph: phenyl
Pp: philippium - rare earth metal that proved to be a mixture of the elements holmium and samarium.
Pr: propyl - (also used for the element praseodymium: see above)
Ps: positronium
R: radical - some unspecified element or radical

Notes

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj 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, three elements, Thorium, Protactinium, and Uranium, have a characteristic terrestrial isotopic composition, and thus their atomic mass given.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj ^ak ^al ^am The isotopic composition of this element varies in some geological specimens, and the variation may exceed the uncertainty stated in the table.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o The isotopic composition varies in terrestrial material such that a more precise atomic weight can not be given.
^ ^a ^b ^c ^d ^e ^f ^g ^h The isotopic composition of the element can vary in commercial materials, which can cause the atomic weight to deviate significantly from the given value.
^ 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.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj ^ak ^al ^am ^an ^ao ^ap ^aq ^ar ^as ^at ^au ^av ^aw ^ax ^ay ^az Name changed due to a standardization of, modernization of, or update to older previously used symbol.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Name designated by discredited/disputed claimant.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x Name proposed prior to discovery/creation of element or prior to official re-naming of a placeholder name.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o Temporary placeholder name.

References

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 Incorporated. 1963.
Leighton, Robert B. Principles of Modern Physics. New York: McGraw-Hill. 1959.

Category: Chemical elements

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "List_of_elements_by_symbol". A list of authors is available in Wikipedia.