Symbol (chemistry)

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See also: Hazard symbol

A chemical symbol is a 1-, 2-, or 3-letter internationally agreed code for a chemical element, usually derived from the name of the element, often in Latin.

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

Only the first letter is capitalized. For example, "He" is the symbol for helium (English name, not known in ancient Roman times), "Pb" for lead (plumbum in Latin), "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 which had the temporary name of unniloctium and "Uuo" is the symbol for ununoctium (temporary name) with the atomic mass 118.

Chemical symbols may be modified by the use of prepended superscripts or subscripts to specify a particular isotope of an atom. Additionally, appended superscripts may be used to indicate the ionization or oxidation state of an element. They are widely used in chemistry and they have been officially chosen by the International Union of Pure and Applied Chemistry. There are also some historical symbols that are currently not official any more.

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)
  • The proton number (atomic number) may be indicated in the left subscript position (e.g., 64Gd)
  • If necessary, a state of ionization or an excited state may be indicated in the right superscript position (e.g., state of ionization Ca2+). In astronomy, non-ionised atomic hydrogen is often known as "H I", and ionised hydrogen as "H II".[1]
  • 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)
  • A radical is indicated by a dot on the right side (e.g., Cl· for a chloride radical)

In Chinese each chemical element has an ideograph, usually created for the purpose, as its symbol (see Chemical elements in East Asian languages).

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.

Current symbols[edit]

Symbol Name Etymology of symbol Atomic number Relative atomic mass Group Period Metallic
character
Ac Actinium from Greek aktinos (ray) 89 &227[227][nb 1]   7 Actinide
Ag Silver Latin argentum (silver) 47 &107.86822107.8682(2)[nb 2] 11 5 Transition metal
Al Aluminium (Aluminum) Latin alumen (alum) 13 &026.9815386826.9815386(8) 13 3 Post-transition metal
Am Americium the Americas 95 &243[243][nb 1]   7 Actinide
Ar Argon Greek argon (inert) 18 &039.948139.948(1)[nb 2][nb 3] 18 3 Noble gas
As Arsenic Greek arsenikos (male) 33 &074.92160274.92160(2) 15 4 Metalloid
At Astatine Greek astatos (unstable) 85 &210[210][nb 1] 17 6 Metalloid
Au Gold Latin aurum (gold) 79 &196.9665694196.966569(4) 11 6 Transition metal
B Boron borax 5 &010.811710.811(7)[nb 2][nb 3][nb 4] 13 2 Metalloid
Ba Barium Greek barys (density) 56 &137.3277137.327(7) 2 6 Alkaline earth metal
Be Beryllium beryl 4 &009.01218239.012182(3) 2 2 Alkaline earth metal
Bh Bohrium Niels Bohr 107 &264[264][nb 1] 7 7 Transition metal
Bi Bismuth from German wiss muth (white-mass), becoming bismuth in English 83 &208.980401208.98040(1) 15 6 Post-transition metal
Bk Berkelium Berkeley, California 97 &247[247][nb 1]   7 Actinide
Br Bromine Greek bromos (stench) 35 &079.904179.904(1) 17 4 Diatomic nonmetal
C Carbon Latin carbo (charcoal) 6 &012.0107812.0107(8)[nb 2][nb 3] 14 2 Polyatomic nonmetal
Ca Calcium Latin calx (lime) 20 &040.078440.078(4)[nb 2] 2 4 Alkaline earth metal
Cd Cadmium Greek kadmia (earth) 48 &112.4118112.411(8)[nb 2] 12 5 Transition metal
Ce Cerium Ceres 58 &140.1161140.116(1)[nb 2]   6 Lanthanide
Cf Californium State and University of California 98 &251[251][nb 1]   7 Actinide
Cl Chlorine Greek chloros (green-yellow) 17 &035.453235.453(2)[nb 2][nb 3][nb 4] 17 3 Diatomic nonmetal
Cm Curium Pierre and Marie Curie and the traditional -um ending 96 &247[247][nb 1]   7 Actinide
Cn Copernicium Nicolaus Copernicus 112 &285[285][nb 1] 12 7 Transition metal
Co Cobalt from German kobold 27 &058.933195558.933195(5) 9 4 Transition metal
Cr Chromium Greek chroma (color) 24 &051.9961651.9961(6) 6 4 Transition metal
Cs Caesium (Cesium) Latin caesius (sky blue) 55 &132.90545192132.9054519(2) 1 6 Alkali metal
Cu Copper Latin Cuprum (Cyprus) 29 &063.546363.546(3)[nb 3] 11 4 Transition metal
Db Dubnium Dubna, Russia 105 &262[262][nb 1] 5 7 Transition metal
Ds Darmstadtium Darmstadt, Germany 110 &271[271][nb 1] 10 7 Unknown
Dy Dysprosium Greek dysprositos 66 &162.5001162.500(1)[nb 2]   6 Lanthanide
Er Erbium Ytterby, Sweden 68 &167.2593167.259(3)[nb 2]   6 Lanthanide
Es Einsteinium Albert Einstein 99 &252[252][nb 1]   7 Actinide
Eu Europium Europe 63 &151.9641151.964(1)[nb 2]   6 Lanthanide
F Fluorine Latin fluo (flow) 9 &018.9984032518.9984032(5) 17 2 Diatomic nonmetal
Fe Iron Latin ferrum (iron) 26 &055.845255.845(2) 8 4 Transition metal
Fl Flerovium Flerov Laboratory of Nuclear Reactions 114 &289[289][nb 1] 14 7 Unknown
Fm Fermium Enrico Fermi 100 &257[257][nb 1]   7 Actinide
Fr Francium France 87 &223[223][nb 1] 1 7 Alkali metal
Ga Gallium Latin Gallia (Gaul) 31 &069.723169.723(1) 13 4 Post-transition metal
Gd Gadolinium gadolinite 64 &157.253157.25(3)[nb 2]   6 Lanthanide
Ge Germanium Germany 32 &072.64172.64(1) 14 4 Metalloid
H Hydrogen Greek hydor gennao (liquid-produce) 1 &001.0079471.00794(7)[nb 2][nb 3][nb 4] 1 1 Diatomic nonmetal
He Helium Greek helios (Sun) 2 &004.00260224.002602(2)[nb 2][nb 3] 18 1 Noble gas
Hf Hafnium Latin Hafnia (Copenhagen) 72 &178.492178.49(2) 4 6 Transition metal
Hg Mercury Greek hydrargyrum (liquid silver) 80 &200.592200.59(2) 12 6 Transition metal
Ho Holmium Latin Holmia (Stockholm) 67 &164.930322164.930 32(2)   6 Lanthanide
Hs Hassium Hesse, Germany 108 &277[277][nb 1] 8 7 Transition metal
I Iodine Greek ioeides (violet) 53 &126.904473126.904 47(3) 17 5 Diatomic nonmetal
In Indium indigo blue 49 &114.8183114.818(3) 13 5 Post-transition metal
Ir Iridium Greek iris (rainbow) 77 &192.2173192.217(3) 9 6 Transition metal
K Potassium Latin kalium (potassium) 19 &039.0983139.0983(1) 1 4 Alkali metal
Kr Krypton Greek kryptos (concealment) 36 &083.798283.798(2)[nb 2][nb 4] 18 4 Noble gas
La Lanthanum Greek lanthano (escape) 57 &138.905477138.90547(7)[nb 2]   6 Lanthanide
Li Lithium Greek lithos (rock) 3 &006.94126.941(2)[nb 2][nb 3][nb 4][nb 5] 1 2 Alkali metal
Lr Lawrencium Ernest O. Lawrence 103 &262[262][nb 1] 3 7 Actinide
Lu Lutetium Latin Lutetia (Paris) 71 &174.9671174.967(1)[nb 2] 3 6 Lanthanide
Lv Livermorium Lawrence Livermore National Laboratory 116 &292[292][nb 1] 16 7 Unknown
Md Mendelevium Dmitri Mendeleyev 101 &258[258][nb 1]   7 Actinide
Mg Magnesium Magnesia, Greece 12 &024.3050624.3050(6) 2 3 Alkaline earth metal
Mn Manganese Greek magnes (magnet) 25 &054.938045554.938045(5) 7 4 Transition metal
Mo Molybdenum Greek molybdos (lead) 42 &095.94295.94(2)[nb 2] 6 5 Transition metal
Mt Meitnerium Lise Meitner 109 &268[268][nb 1] 9 7 Unknown
N Nitrogen Greek nitron (niter) 7 &014.0067214.0067(2)[nb 2][nb 3] 15 2 Diatomic nonmetal
Na Sodium Latin natrium (sodium) 11 &022.98976928222.98976928(2) 1 3 Alkali metal
Nb Niobium Niobe 41 &092.90638292.906 38(2) 5 5 Transition metal
Nd Neodymium Greek neos didymos (novelty-twin) 60 &144.2423144.242(3)[nb 2]   6 Lanthanide
Ne Neon Greek neos (novelty) 10 &020.1797620.1797(6)[nb 2][nb 4] 18 2 Noble gas
Ni Nickel German kupfernickel (nickeline) 28 &058.6934258.6934(2) 10 4 Transition metal
No Nobelium Alfred Nobel 102 &259[259][nb 1]   7 Actinide
Np Neptunium Neptune 93 &237[237][nb 1]   7 Actinide
O Oxygen Greek oxys (acid) 8 &015.9994315.9994(3)[nb 2][nb 3] 16 2 Diatomic nonmetal
Os Osmium Greek osme (odor) 76 &190.233190.23(3)[nb 2] 8 6 Transition metal
P Phosphorus Greek phosphoros (light bearer) 15 &030.973762230.973762(2) 15 3 Polyatomic nonmetal
Pa Protactinium Greek protos and actinium 91 &231.035882231.03588(2)[nb 1]   7 Actinide
Pb Lead Latin plumbum (lead) 82 &207.21207.2(1)[nb 2][nb 3] 14 6 Post-transition metal
Pd Palladium Pallas (genitive Pallados) 46 &106.421106.42(1)[nb 2] 10 5 Transition metal
Pm Promethium Prometheus 61 &145[145][nb 1]   6 Lanthanide
Po Polonium Poland 84 &210[210][nb 1] 16 6 Post-transition metal
Pr Praseodymium Greek prasios (green) 59 &140.907652140.90765(2)   6 Lanthanide
Pt Platinum Spanish platina (silver) 78 &195.0849195.084(9) 10 6 Transition metal
Pu Plutonium Pluto 94 &244[244][nb 1]   7 Actinide
Ra Radium Latin radius (ray) 88 &226[226][nb 1] 2 7 Alkaline earth metal
Rb Rubidium Latin rubidus (red) 37 &085.4678385.4678(3)[nb 2] 1 5 Alkali metal
Re Rhenium German Rheinprovinz 75 &186.2071186.207(1) 7 6 Transition metal
Rf Rutherfordium Ernest Rutherford 104 &261261[nb 1] 4 7 Transition metal
Rg Roentgenium Wilhelm Conrad Röntgen 111 &272[272][nb 1] 11 7 Unknown
Rh Rhodium Greek rhodon (rose) 45 &102.905502102.905 50(2) 9 5 Transition metal
Rn Radon radium and emanation 86 &220[220][nb 1] 18 6 Noble gas
Ru Ruthenium Latin Ruthenia (Russia) 44 &101.072101.07(2)[nb 2] 8 5 Transition metal
S Sulfur (Sulphur) Latin sulfur 16 &032.065532.065(5)[nb 2][nb 3] 16 3 Polyatomic nonmetal
Sb Antimony Latin stibium (eye liner) 51 &121.7601121.760(1)[nb 2] 15 5 Metalloid
Sc Scandium Scandinavia 21 &044.955912644.955912(6) 3 4 Transition metal
Se Selenium Greek selene (Moon) 34 &078.96378.96(3)[nb 3] 16 4 Polyatomic nonmetal
Sg Seaborgium Glenn T. Seaborg 106 &266[266][nb 1] 6 7 Transition metal
Si Silicon Latin silex (flint) 14 &028.0855328.0855(3)[nb 3] 14 3 Metalloid
Sm Samarium samarskite 62 &150.362150.36(2)[nb 2]   6 Lanthanide
Sn Tin Latin stannum (tin) 50 &118.7101118.710(7)[nb 2] 14 5 Post-transition metal
Sr Strontium Strontian 38 &087.62187.62(1)[nb 2][nb 3] 2 5 Alkaline earth metal
Ta Tantalum King Tantalus 73 &180.947882180.94788(2) 5 6 Transition metal
Tb Terbium Ytterby, Sweden 65 &158.925352158.92535(2)   6 Lanthanide
Tc Technetium Greek technetos (artificial) 43 &098[98][nb 1] 7 5 Transition metal
Te Tellurium Greek tellus (Earth) 52 &127.603127.60(3)[nb 2] 16 5 Metalloid
Th Thorium Thor 90 &232.038062232.03806(2)[nb 1][nb 2]   7 Actinide
Ti Titanium the Titans 22 &047.867147.867(1) 4 4 Transition metal
Tl Thallium Greek thallos (shoot) 81 &204.38332204.3833(2) 13 6 Post-transition metal
Tm Thulium Thule and the traditional -ium ending 69 &168.934212168.93421(2)   6 Lanthanide
U Uranium Uranus 92 &238.028913238.02891(3)[nb 1][nb 2][nb 4]   7 Actinide
Uuo Ununoctium Latin uni, uni, and oct (one, one, eight) 118 &294[294][nb 1] 18 7 Unknown
Uup Ununpentium Latin uni, uni, and Greek pent (one, one, five) 115 &288[288][nb 1] 15 7 Unknown
Uus Ununseptium Latin uni, uni, and sept (one, one, seven) 117 &294[294][nb 1] 17 7 Unknown
Uut Ununtrium Latin uni, uni, and Greek tri (one, one, three) 113 &284[284][nb 1] 13 7 Unknown
V Vanadium Vanadis 23 &050.9415150.9415(1) 5 4 Transition metal
W Tungsten German wolfram (wolf-froth) 74 &183.841183.84(1) 6 6 Transition metal
Xe Xenon Greek xenos (alien) 54 &131.2936131.293(6)[nb 2][nb 4] 18 5 Noble gas
Y Yttrium Ytterby, Sweden 39 &088.90585288.90585(2) 3 5 Transition metal
Yb Ytterbium Ytterby, Sweden 70 &173.043173.04(3)[nb 2]   6 Lanthanide
Zn Zinc German zin (tin) 30 &065.409465.409(4) 12 4 Transition metal
Zr Zirconium zircon 40 &091.224291.224(2)[nb 2] 4 5 Transition metal
Legend for category color
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 not currently used[edit]

The following is a list of symbols 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
A Argon 18 Current symbol is Ar. [nb 6]
Ab Alabamine 85 Discredited claim to discovery of astatine. [nb 7]
Ad Aldebaranium 70 Former name of ytterbium. [nb 7]
Am Alabamium 85 Discredited claim to discovery of astatine. The symbol is now used for americium [nb 7]
An Athenium 99 Proposed name for einsteinium. [nb 8]
Ao Ausonium 93 Discredited claim to discovery of neptunium. [nb 7]
Az Azote 7 Former name for nitrogen. [nb 6]
Bo Boron 5 Current symbol is B. [nb 6]
Bv Brevium 91 Former name for protactinium. [nb 6]
Bz Berzelium 59 Suggested name for praseodymium. [nb 8]
Cb Columbium 41 Former name of niobium. [nb 6]
Cb Columbium 95 Suggested name for americium. [nb 8]
Ch Chromium 24 Current symbol is Cr. [nb 6]
Cl Columbium 41 Former name of niobium. The symbol is now used for chlorine. [nb 6]
Cp Cassiopeium 71 Former name for lutetium. [nb 6]
Ct Centurium 100 Proposed name for fermium. [nb 8]
Ct Celtium 72 Former name of hafnium. [nb 6]
Da Danubium 43 Suggested name for technetium. [nb 8]
Db Dubnium 104 Proposed name for rutherfordium. The symbol and name were used for element 105. [nb 6][nb 8]
E Einsteinium 99 Current symbol is Es. [nb 6]
Ea Ekaaluminium 31 Name given by Mendeleev to an as of then undiscovered element. When discovered, gallium closely matched the prediction. [nb 8][nb 9]
Eb Ekaboron 21 Name given by Mendeleev to an as of then undiscovered element. When discovered, scandium closely matched the prediction. [nb 8][nb 9]
El Ekaaluminium 31 Name given by Mendeleev to an as of then undiscovered element. When discovered, gallium closely matched the prediction. [nb 8][nb 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). [nb 6]
Em Ekamanganese 43 Name given by Mendeleev to an as of then undiscovered element. When discovered, technetium closely matched the prediction. [nb 8][nb 9]
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 8][nb 9]
Es Esperium 94 Discredited claim to discovery of plutonium. The symbol is now used for einsteinium. [nb 7]
Fa Francium 87 Current symbol is Fr. [nb 6]
Fl Fluorine 9 Current symbol is F. The letters are now used for flerovium. [nb 6]
Fl Florentium 61 Discredited claim to discovery of promethium. The symbol is now used for flerovium. [nb 7]
Fr Florentium 61 Discredited claim to discovery of promethium. The symbol is now used for francium. [nb 7]
G Glucinium 4 Former name of beryllium. [nb 6]
Gl Glucinium 4 Former name of beryllium. [nb 6]
Ha Hahnium 105 Proposed name for dubnium. [nb 8]
Hn Hahnium 108 Proposed name for hassium. [nb 8]
Hy Mercury 80 Current symbol is Hg. [nb 6]
I Iridium 77 Current symbol is Ir. The symbol is now used for iodine. [nb 6]
Il Illinium 61 Discredited claim to discovery of promethium. [nb 7]
J Jodium 53 Old name of iodine. [nb 6]
Jg Jargonium 72 Discredited claim to discovery of hafnium. [nb 7]
Jl Joliotium 105 Proposed name for dubnium. [nb 8]
Ku Kurchatovium 104 Proposed name for rutherfordium. [nb 8]
Lw Lawrencium 103 Current symbol is Lr. [nb 6]
M Muriaticum 17 Former name of chlorine. [nb 6]
Ma Manganese 25 Current symbol is Mn. [nb 6]
Ma Masurium 43 Disputed claim to discovery of technetium. [nb 7]
Md Mendelevium 97 Proposed name for berkelium. The symbol and name were later used for element 101. [nb 6][nb 8]
Me Mendelevium 68 Suggested name for erbium. [nb 6]
Ml Moldavium 87 Suggested name for francium. [nb 8]
Ms Magnesium 12 Current symbol is Mg. [nb 6]
Ms Masrium 49 Discredited claim of discovery of indium. [nb 7]
Mt Meitnium 91 Suggested name for protactinium. The symbol is now used for meitnerium. [nb 8]
Mv Mendelevium 101 Current symbol is Md. [nb 6]
Ng Norwegium 72 Discredited claim to discovery of hafnium. [nb 7]
No Norium 72 Discredited claim to discovery of hafnium. The symbol is now used for nobelium. [nb 7]
Ns Nielsbohrium 105 Proposed name for dubnium. [nb 8]
Ns Nielsbohrium 107 Proposed name for bohrium. [nb 8]
Nt Niton 86 Former name for radon. [nb 6]
Ny Neoytterbium 70 Former name of ytterbium. [nb 6]
Od Odinium 62 Suggested name for samarium. [nb 8]
P Lead 82 Current symbol is Pb. The symbol is now used for phosphorus. [nb 6]
Pa Palladium 46 Current symbol is Pd. The symbol is now used for protactinium. [nb 6]
Pe Pelopium 41 Former name for niobium. [nb 6]
Pl Palladium 46 Current symbol is Pd. [nb 6]
Po Potassium 19 Current symbol is K. The letters were later used for polonium. [nb 6]
R Rhodium 45 Current symbol is Rh. [nb 6]
Rf Rutherfordium 106 Proposed name for seaborgium. The symbol and name were instead used for element 104. [nb 6][nb 8]
Ro Rhodium 45 Current symbol is Rh. [nb 6]
Sa Samarium 62 Current symbol is Sm. [nb 6]
So Sodium 11 Current symbol is Na. [nb 6]
Sp Spectrium 70 Suggested name for ytterbium. [nb 8]
St Tin 50 Current symbol is Sn. [nb 6]
St Antimony 51 Current symbol is Sb. [nb 6]
Tn Tungsten 74 Current symbol is W. [nb 6]
Tu Thulium 69 Current symbol is Tm. [nb 6]
Tu Tungsten 74 Current symbol is W. [nb 6]
Ty Tyrium 60 Suggested name for neodymium. [nb 8]
Unb Unnilbium 102 Temporary name given to nobelium until it was permanently named by IUPAC. [nb 9]
Une Unnilennium 109 Temporary name given to meitnerium until it was permanently named by IUPAC. [nb 9]
Unh Unnilhexium 106 Temporary name given to seaborgium until it was permanently named by IUPAC. [nb 9]
Uno Unniloctium 108 Temporary name given to hassium until it was permanently named by IUPAC. [nb 9]
Unp Unnilpentium 105 Temporary name given to dubnium until it was permanently named by IUPAC. [nb 9]
Unq Unnilquadium 104 Temporary name given to rutherfordium until it was permanently named by IUPAC. [nb 9]
Uns Unnilseptium 107 Temporary name given to bohrium until it was permanently named by IUPAC. [nb 9]
Unt Unniltrium 103 Temporary name given to lawrencium until it was permanently named by IUPAC. [nb 9]
Unu Unnilunium 101 Temporary name given to mendelevium until it was permanently named by IUPAC. [nb 9]
Uub Ununbium 112 Temporary name given to copernicium until it was permanently named by IUPAC. [nb 9]
Uuh Ununhexium 116 Temporary name given to livermorium until it was permanently named by IUPAC. [nb 9]
Uun Ununnilium 110 Temporary name given to darmstadtium until it was permanently named by IUPAC. [nb 9]
Uuq Ununquadium 114 Temporary name given to flerovium until it was permanently named by IUPAC. [nb 9]
Uuu Unununium 111 Temporary name given to roentgenium until it was permanently named by IUPAC. [nb 9]
Ur Uranium 92 Current symbol is U. [nb 6]
Vi Virginium 87 Discredited claim to discovery of francium. [nb 7]
Vm Virginium 87 Discredited claim to discovery of francium. [nb 7]
Yt Yttrium 39 Current symbol is Y. [nb 6]

Pictographic symbols[edit]

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
Sun symbol.svg Hydrogen Hydrogen 1 Daltonian symbol circa 1808.
Sulfur symbol 1.png Sulfur Sulfur 16 Alchemical symbol.
Sulfur symbol 2.png Pallas Sulfur 16 Alchemical symbol.
🜍 Sulfur Sulfur 16 Alchemical symbol.
Sulfur Sulfur 16 Daltonian symbol circa 1808.
Magnesium Magnesium 12 Alchemical symbol.
Mars Iron 26 Alchemical symbol.
Marian star four-tenths.svg Stellae Fixae Copper 29 Pre-16th century alchemical symbol.
Venus Copper 29 Alchemical symbol.
Copper symbol.svg Copper Copper 29 Alchemical symbol.
© Copper Copper 29 Daltonian symbol circa 1808.
Arsenic alchemical symbol.svg Arsenic Arsenic 33 Alchemical symbol.
🜺 Arsenic Arsenic 33 Alchemical symbol.
Luna Silver 47 Alchemical symbol.
🜛 Silver Silver 47 Alchemical symbol.
Iupiter Tin 50 Alchemical symbol.
Antimony Antimony 51 Alchemical symbol.
Antimony-symbol.png Antimony Antimony 51 Alchemical symbol.
Platinum Platinum 78 Alchemical symbol.
Platinum Platinum 78 Alchemical symbol.
Uranus symbol.svg Uranus Platinum 78 Alchemical symbol.
Sol Gold 79 Alchemical symbol from the 16th century.
Sun symbol.svg Sol Gold 79 Alchemical symbol from 1700 through 1783.
🜚 Gold Gold 79 Alchemical symbol.
Pisces.svg Pisces Mercury 80 Pre-16th century alchemical symbol.
Neptune symbol.svg 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.
Bismuth symbol.png Taurus Bismuth 83 Alchemical symbol.

Symbols for named isotopes[edit]

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. 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.[2]

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[edit]

General:

From organic chemistry:

From inorganic chemistry:

See also[edit]

Notes[edit]

  1. ^ 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 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. ^ 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.
  3. ^ 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.
  4. ^ 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.
  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. ^ 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 Name changed due to a standardization of, modernization of, or update to older formerly-used symbol.
  7. ^ a b c d e f g h i j k l m n o Name designated by discredited/disputed claimant.
  8. ^ 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.
  9. ^ a b c d e f g h i j k l m n o p q r s Temporary placeholder name.

References[edit]

  1. ^ The interstellar medium, with definition of HI and HII regions
  2. ^ 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." 
  • 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.
  • Scerri, E.R. "The Periodic Table, Its Story and Its Significance". New York, Oxford University Press. 2007.

External links[edit]