LIST OF ELEMENTS BY SYMBOL

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.

Contents

Current symbols

Symbols not currently used

Pictographic symbols

Symbols for named isotopes

Other symbols that look like element symbols

Notes

References

External links

Current symbols

Symbol	Name	Etymology of Symbol	Atomic Number	Relative Atomic Mass	Group	Period
Ac	Actinium	corruption of the Greek '''ak'tinos''	89	[227][1]		7
Ag	Silver	Latin '''a'r'g'entum''	47	107.8682(2)[2]	11	5
Al	Aluminium (Aluminum)	Latin '''al'umen''	13	26.9815386(8)	13	3
Am	Americium	the 'Am'ericas	95	[243]1		7
Ar	Argon	Greek '''ar'gon''	18	39.948(1)2 [3]	18	3

|-style="background-color:#cccc99"
|As||Arsenic||Greek '''a'r's'enikos''||33||74.92160(2)||15||4
|-style="background-color:#ffff99"
|At||Astatine||Greek '''a's't'atos''||85||[210]¹||17||6
|-style="background-color:#ffc0c0"
|Au||Gold||Latin '''au'rum''||79||196.966569(4)||11||6
|-style="background-color:#cccc99"
|B||Boron||'b'orax||5||10.811(7)^{2 [4] 3}||13||2
|-style="background-color:#ffdead"
|Ba||Barium||Greek '''ba'rys''||56||137.327(7)||2||6
|-style="background-color:#ffdead"
|Be||Beryllium||'be'ryl||4||9.012182(3)||2||2
|-style="background-color:#ffc0c0"
|Bh||Bohrium||Neils 'B'o'h'r||107||[264]¹||7||7
|-style="background-color:#cccccc"
|Bi||Bismuth||corruption of the German '''wi'ss''''muth''||83||208.98040(1)||15||6
|-style="background-color:#ff99cc"
|Bk||Berkelium||'B'er'k'eley, California||97||[247]¹|| ||7
|-style="background-color:#ffff99"
|Br||Bromine||Greek '''br'omos''||35||79.904(1)||17||4
|-style="background-color:#a0ffa0"
|C||Carbon||Latin '''c'arbo''||6||12.0107(8)^{2 3}||14||2
|-style="background-color:#ffdead"
|Ca||Calcium||Latin '''ca'lx''||20||40.078(4)²||2||4
|-style="background-color:#ffc0c0"
|Cd||Cadmium||corruption of the Greek '''k'a'd'mia''||48||112.411(8)²||12||5
|-style="background-color:#ffbfff"
|Ce||Cerium||'Ce'res||58||140.116(1)²|| ||6
|-style="background-color:#ff99cc"
|Cf||Californium||State and University of 'C'ali'f'ornia||98||[251]¹|| ||7
|-style="background-color:#ffff99"
|Cl||Chlorine||Greek '''c'h'l'oros''||17||35.453(2)^{2 4 3}||17||3
|-style="background-color:#ff99cc"
|Cm||Curium||Pierre and Marie 'C'urie and the traditional -u'm' ending||96||[247]¹|| ||7
|-style="background-color:#ffc0c0"
|Co||Cobalt||corruption of the German '''ko'bold''||27||58.933195(5)||9||4
|-style="background-color:#ffc0c0"
|Cr||Chromium||Greek '''c'h'r'oma''||24||51.9961(6)||6||4
|-style="background-color:#ff6666"
|Cs||Caesium (Cesium)||Latin '''c'ae's'ius''||55||132.9054519(2)||1||6
|-style="background-color:#ffc0c0"
|Cu||Copper||Latin '''Cu'prum''||29||63.546(3)³||11||4
|-style="background-color:#ffc0c0"
|Db||Dubnium||'D'u'b'na, Russia||105||[262]¹||5||7
|-style="background-color:#ffc0c0"
|Ds||Darmstadtium||'D'arm's'tadt, Germany||110||[271]¹||10||7
|-style="background-color:#ffbfff"
|Dy||Dysprosium||Greek '''dy'sprositos''||66||162.500(1)²|| ||6
|-style="background-color:#ffbfff"
|Er||Erbium||Ytt'er'by, Sweden||68||167.259(3)²|| ||6
|-style="background-color:#ff99cc"
|Es||Einsteinium||Albert 'E'in's'tein||99||[252]¹|| ||7
|-style="background-color:#ffbfff"
|Eu||Europium||'Eu'rope||63||151.964(1)²|| ||6
|-style="background-color:#ffff99"
|F||Fluorine||Latin '''f'luo''||9||18.9984032(5)||17||2
|-style="background-color:#ffc0c0"
|Fe||Iron||Latin '''fe'rrum''||26||55.845(2)||8||4
|-style="background-color:#ff99cc"
|Fm||Fermium||Enrico 'F'er'm'i||100||[257]¹|| ||7
|-style="background-color:#ff6666"
|Fr||Francium||'Fr'ance||87||[223]¹||1||7
|-style="background-color:#cccccc"
|Ga||Gallium||Latin '''Ga'llia''||31||69.723(1)||13||4
|-style="background-color:#ffbfff"
|Gd||Gadolinium||'g'a'd'olinite||64||157.25(3)²|| ||6
|-style="background-color:#cccc99"
|Ge||Germanium||'Ge'rmany||32||72.64(1)||14||4
|-style="background-color:#a0ffa0"
|H||Hydrogen||Greek '''h'ydror''||1||1.00794(7)^{2 4 3}||1||1
|-style="background-color:#c0ffff"
|He||Helium||Greek '''he'lios''||2||4.002602(2)^{2 3}||18||1
|-style="background-color:#ffc0c0"
|Hf||Hafnium||Latin '''H'a'f'nia''||72||178.49(2)||4||6
|-style="background-color:#ffc0c0"
|Hg||Mercury||Latin '''h'ydr''''ar'g'yrum''||80||200.59(2)||12||6
|-style="background-color:#ffbfff"
|Ho||Holmium||Latin '''Ho'lmia''||67||164.930 32(2)|| ||6
|-style="background-color:#ffc0c0"
|Hs||Hassium||'H'e's'se, Germany||108||[277]¹||8||7
|-style="background-color:#ffff99"
|I||Iodine||Greek '''i'oeides''||53||126.904 47(3)||17||5
|-style="background-color:#cccccc"
|In||Indium||'in'digo blue||49||114.818(3)||13||5
|-style="background-color:#ffc0c0"
|Ir||Iridium||Greek '''ir'is''||77||192.217(3)||9||6
|-style="background-color:#ff6666"
|K||Potassium (Kalium)||Latin '''k'alium''||19||39.0983(1)||1||4
|-style="background-color:#c0ffff"
|Kr||Krypton||Greek '''kr'yptos''||36||83.798(2)^{2 4}||18||4
|-style="background-color:#ffbfff"
|La||Lanthanum||Greek '''la'nthanien''||57||138.90547(7)²|| ||6
|-style="background-color:#ff6666"
|Li||Lithium||Greek '''li'thos''||3||6.941(2)^{2 4 3 [5]}||1||2
|-style="background-color:#ff99cc"
|Lr||Lawrencium||Ernest O. 'L'aw'r'ence||103||[262]¹||3||7
|-style="background-color:#ffbfff"
|Lu||Lutetium||Latin '''Lu'tetia''||71||174.967(1)²||3||6
|-style="background-color:#ff99cc"
|Md||Mendelevium||Dmitri 'M'en'd'eleyev||101||[258]¹|| ||7
|-style="background-color:#ffdead"
|Mg||Magnesium||'M'a'g'nesia, Greece||12||24.3050(6)||2||3
|-style="background-color:#ffc0c0"
|Mn||Manganese||Latin '''m'ag'n'es''||25||54.938045(5)||7||4
|-style="background-color:#ffc0c0"
|Mo||Molybdenum||Greek '''mo'lybdos''||42||95.94(2)²||6||5
|-style="background-color:#ffc0c0"
|Mt||Meitnerium||Lise 'M'ei't'ner||109||[268]¹||9||7
|-style="background-color:#a0ffa0"
|N||Nitrogen||Greek '''n'itron''||7||14.0067(2)^{2 3}||15||2
|-style="background-color:#ff6666"
|Na||Sodium||Latin '''na'trium''||11||22.98976928(2)||1||3
|-style="background-color:#ffc0c0"
|Nb||Niobium||'N'io'b'e||41||92.906 38(2)||5||5
|-style="background-color:#ffbfff"
|Nd||Neodymium||Greek '''d'idymos''||60||144.242(3)²|| ||6
|-style="background-color:#c0ffff"
|Ne||Neon||Greek '''ne'os''||10||20.1797(6)^{2 4}||18||2
|-style="background-color:#ffc0c0"
|Ni||Nickel||German ''kupfer'ni'ckel''||28||58.6934(2)||10||4
|-style="background-color:#ff99cc"
|No||Nobelium||Alfred 'No'bel||102||[259]¹|| ||7
|-style="background-color:#ff99cc"
|Np||Neptunium||'N'e'p'tune||93||[237]¹|| ||7
|-style="background-color:#a0ffa0"
|O||Oxygen||Greek '''o'xys''||8||15.9994(3)^{2 3}||16||2
|-style="background-color:#ffc0c0"
|Os||Osmium||Greek '''os'me''||76||190.23(3)²||8||6
|-style="background-color:#a0ffa0"
|P||Phosphorus||Greek '''p'hos''''phoros''||15||30.973762(2)||15||3
|-style="background-color:#ff99cc"
|Pa||Protactinium||Greek '''p'rotos'' and 'a'ctinium||91||231.03588(2)¹|| ||7
|-style="background-color:#cccccc"
|Pb||Lead||Latin '''p'lum'b'um''||82||207.2(1)^{2 3}||14||6
|-style="background-color:#ffc0c0"
|Pd||Palladium||'P'allas and the traditional -'d'ium ending||46||106.42(1)²||10||5
|-style="background-color:#ffbfff"
|Pm||Promethium||'P'ro'm'etheus||61||[145]¹|| ||6
|-style="background-color:#cccc99"
|Po||Polonium||'Po'land||84||[210]¹||16||6
|-style="background-color:#ffbfff"
|Pr||Praseodymium||Greek '''pr'asios''||59||140.90765(2)|| ||6
|-style="background-color:#ffc0c0"
|Pt||Platinum||Greek '''p'la't'''''ina''||78||195.084(9)||10||6
|-style="background-color:#ff99cc"
|Pu||Plutonium||'P'l'u'to||94||[244]¹|| ||7
|-style="background-color:#ffdead"
|Ra||Radium||Latin '''ra'dius''||88||[226]¹||2||7
|-style="background-color:#ff6666"
|Rb||Rubidium||Latin '''r'u'b'idus''||37||85.4678(3)²||1||5
|-style="background-color:#ffc0c0"
|Re||Rhenium||German '''R'h'e'inprovinz''||75||186.207(1)||7||6
|-style="background-color:#ffc0c0"
|Rf||Rutherfordium||Ernest 'R'uther'f'ord||104||261¹||4||7
|-style="background-color:#ffc0c0"
|Rg||Roentgenium||Wilhelm Conrad 'R'önt'g'en||111||[272]¹||11||7
|-style="background-color:#ffc0c0"
|Rh||Rhodium||Greek '''rh'odon''||45||102.905 50(2)||9||5
|-style="background-color:#c0ffff"
|Rn||Radon||'r'adium and emanatio'n'||86||[220]¹||18||6
|-style="background-color:#ffc0c0"
|Ru||Ruthenium||Latin '''Ru'thenia''||44||101.07(2)²||8||5
|-style="background-color:#a0ffa0"
|S||Sulfur (Sulphur)||Latin '''s'ulfur''||16||32.065(5)^{2 3}||16||3
|-style="background-color:#cccc99"
|Sb||Antimony||Latin '''s'ti'b'ium''||51||121.760(1)²||15||5
|-style="background-color:#ffc0c0"
|Sc||Scandium||'Sc'andinavia||21||44.955912(6)||3||4
|-style="background-color:#a0ffa0"
|Se||Selenium||Greek '''se'lene''||34||78.96(3)³||16||4
|-style="background-color:#ffc0c0"
|Sg||Seaborgium||Glenn T. 'S'eabor'g'||106||[266]¹||6||7
|-style="background-color:#cccc99"
|Si||Silicon||Latin '''si'lex''||14||28.0855(3)³||14||3
|-style="background-color:#ffbfff"
|Sm||Samarium||'s'a'm'arskite||62||150.36(2)²|| ||6
|-style="background-color:#cccccc"
|Sn||Tin||Latin '''s'ta'n'num''||50||118.710(7)²||14||5
|-style="background-color:#ffdead"
|Sr||Strontium||Latin '''S't'r'ontian''||38||87.62(1)^{2 3}||2||5
|-style="background-color:#ffc0c0"
|Ta||Tantalum||King 'Ta'ntalus||73||180.94788(2)||5||6
|-style="background-color:#ffbfff"
|Tb||Terbium||Yt't'er'b'y, Sweden||65||158.92535(2)|| ||6
|-style="background-color:#ffc0c0"
|Tc||Technetium||Greek '''t'e'c'hnetos''||43||[98]¹||7||5
|-style="background-color:#cccc99"
|Te||Tellurium||Greek '''te'llus''||52||127.60(3)²||16||5
|-style="background-color:#ff99cc"
|Th||Thorium||'Th'or||90||232.03806(2)^{1 2}|| ||7
|-style="background-color:#ffc0c0"
|Ti||Titanium||the 'Ti'tans||22||47.867(1)||4||4
|-style="background-color:#cccccc"
|Tl||Thallium||Greek '''t'ha'l'los''||81||204.3833(2)||13||6
|-style="background-color:#ffbfff"
|Tm||Thulium||'T'hule and the traditional -iu'm' ending||69||168.93421(2)|| ||6
|-style="background-color:#ff99cc"
|U||Uranium||'U'ranus||92||238.02891(3)^{1 2 4}|| ||7
|-style="background-color:#ffc0c0"
|Uub||Ununbium||Latin '''u'ni'', '''u'ni'', and '''b'i''||112||[285]¹||12||7
|-style="background-color:#cccccc"
|Uuh||Ununhexium||Latin '''u'ni'', '''u'ni'', and Greek '''h'ex''||116||[292]¹||16||7
|-style="background-color:#c0ffff"
|Uuo||Ununoctium||Latin '''u'ni'', '''u'ni'', and '''o'ct''||118||[294]¹||18||7
|-style="background-color:#cccccc"
|Uup||Ununpentium||Latin '''u'ni'', '''u'ni'', and Greek '''p'ent''||115||[288]¹||15||7
|-style="background-color:#cccccc"
|Uuq||Ununquadium||Latin '''u'ni'', '''u'ni'', and '''q'uadr''||114||[289]¹||14||7
|-style="background-color:#cccccc"
|Uut||Ununtrium||Latin '''u'ni'', '''u'ni'', and Greek '''t'ri''||113||[284]¹||13||7
|-style="background-color:#ffc0c0"
|V||Vanadium||'V'anadis||23||50.9415(1)||5||4
|-style="background-color:#ffc0c0"
|W||Tungsten||German '''w'ol''''fram''||74||183.84(1)||6||6
|-style="background-color:#c0ffff"
|Xe||Xenon||Greek '''xe'nos''||54||131.293(6)^{2 4}||18||5
|-style="background-color:#ffc0c0"
|Y||Yttrium||'Y'tterby, Sweden||39||88.90585(2)||3||5
|-style="background-color:#ffbfff"
|Yb||Ytterbium||'Y'tter'b'y, Sweden||70||173.04(3)²|| ||6
|-style="background-color:#ffc0c0"
|Zn||Zinc||German '''z'i'n'''||30||65.409(4)||12||4
|-style="background-color:#ffc0c0"
|Zr||Zirconium||'z'i'r'con||40||91.224(2)²||4||5
|}

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
Nw	Newtonium	67	Suggested name for holmium.	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	Name	Atomic Number	Origin of Symbol	Why Not Used
	Hydrogen	1	Daltonian symbol circa 1808.	6
	Sulfur	16	Alchemical symbol.	6
	Pallas	16	Alchemical symbol.	6
	Sulfur	16	Daltonian symbol circa 1808.	6
⊛	Magnesium	21	Alchemical symbol.	6
♂	Mars	26	Alchemical symbol.	6
	''Stellae Fixae''	29	Pre-1500s alchemical symbol.	6
♀	Venus	29	Alchemical symbol.	6
	Copper	29	Alchemical symbol.	6
©	Copper	29	Daltonian symbol circa 1808.	6
	Arsenic	33	Alchemical symbol.	6
	Luna	48	Alchemical symbol.	6
	Iupiter	50	Alchemical symbol.	6
♁	Antimony	51	Alchemical symbol.	6
	Antimony	51	Alchemical symbol.	6
☾	Platinum	78	Alchemical symbol.	6
☉	Platinum	78	Alchemical symbol.	6
	Uranus	78	Alchemical symbol.	6
☼	Sol	79	Alchemical symbol from the 1500s	6
	Sol	79	Alchemical symbol from 1700 through 1783.	6
[1]	Pisces	80	Pre-1500s alchemical symbol.	6
	Neptunus	80	Alchemical symbol from the 1600s.	6
	Mercurius	80	Alchemical symbol from 1700 through 1783.	6
	Saturnus	82	Alchemical symbol circa 1783.	6
	Taurus	83	Alchemical symbol.	6

1. 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.
2. The isotopic composition of this element varies in some geological specimens, and the variation may exceed the uncertainty stated in the table.
3. The isotopic composition varies in terrestrial material such that a more precise atomic weight can not be given.
4. 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. 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.
6. Name changed due to a standardization of, modernization of, or update to older previously used symbol.

7. Name designated by discredited/disputed claimant.

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

9. 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 ''actin''ium and emanati''on''. 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 ''rad''ium and emanati''on''. 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 ''thor''ium and emanati''on''. 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

1. 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.
2. The isotopic composition of this element varies in some geological specimens, and the variation may exceed the uncertainty stated in the table.
3. The isotopic composition varies in terrestrial material such that a more precise atomic weight can not be given.
4. 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. 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.
6. Name changed due to a standardization of, modernization of, or update to older previously used symbol.

7. Name designated by discredited/disputed claimant.

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

9. 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.

External links

★ Berzelius’ List of Elements

★ History of IUPAC Atomic Weight Values (1883 to 1997)