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Chemical symbol
Abbreviations used in chemistry

Chemical symbols are the abbreviations used in chemistry, mainly for chemical elements; but also for functional groups, chemical compounds, and other entities. Element symbols for chemical elements, also known as atomic symbols, normally consist of one or two letters from the Latin alphabet and are written with the first letter capitalised.

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History

Earlier symbols for chemical elements stem from classical Latin and Greek words. 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, Pb is the symbol for lead (plumbum in Latin); Hg is the symbol for mercury (hydrargyrum in Greek); and He is the symbol for helium (a Neo-Latin name) because helium was not known in ancient Roman times. Some symbols come from other sources, like W for tungsten (Wolfram in German) which was not known in Roman times.

A three-letter temporary symbol may be assigned to a newly synthesized (or not yet synthesized) element. For example, "Uno" was the temporary symbol for hassium (element 108) which had the temporary name of unniloctium, based on the digits of its atomic number. There are also some historical symbols that are no longer officially used.

Extension of the symbol

In addition to the letters for the element itself, additional details may be added to the symbol as superscripts or subscripts a particular isotope, ionization, or oxidation state, or other atomic detail.1 A few isotopes have their own specific symbols rather than just an isotopic detail added to their element symbol.

Attached subscripts or superscripts specifying a nuclide 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 implicitly understood if unspecified.
  • 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, as generally true for nonbonded valence electrons in skeletal structures.

Many functional groups also have their own chemical symbol, e.g. Ph for the phenyl group, and Me for the methyl group.

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.

Symbols for chemical elements

List of chemical elements
ZSymbolNameOrigin of name23
1HHydrogenGreek elements hydro- and -gen, meaning 'water-forming'
2HeHeliumGreek hḗlios, 'sun'
3LiLithiumGreek líthos, 'stone'
4BeBerylliumberyl, a mineral (ultimately from the name of Belur in southern India)
5BBoronborax, a mineral (from Arabic bawraq)
6CCarbonLatin carbo, 'coal'
7NNitrogenGreek nítron and -gen, meaning 'niter-forming'
8OOxygenGreek oxy- and -gen, meaning 'acid-forming'
9FFluorineLatin fluere, 'to flow'
10NeNeonGreek néon, 'new'
11NaSodiumEnglish soda (the symbol Na is derived from Neo-Latin natrium, coined from German Natron, 'natron')
12MgMagnesiumMagnesia, a district of Eastern Thessaly in Greece
13AlAluminiumalumina, from Latin alumen (gen. alumni), 'bitter salt, alum'
14SiSiliconLatin silex, 'flint' (originally silicium)
15PPhosphorusGreek phōsphóros, 'light-bearing'
16SSulfurLatin sulphur, 'brimstone'
17ClChlorineGreek chlōrós, 'greenish yellow'
18ArArgonGreek argós, 'idle' (because of its inertness)
19KPotassiumNeo-Latin potassa, 'potash' (the symbol K is derived from Latin kalium)
20CaCalciumLatin calx, 'lime'
21ScScandiumLatin Scandia, 'Scandinavia'
22TiTitaniumTitans, the sons of the Earth goddess of Greek mythology
23VVanadiumVanadis, an Old Norse name for the Scandinavian goddess Freyja
24CrChromiumGreek chróma, 'colour'
25MnManganesecorrupted from magnesia negra; see Magnesium
26FeIronEnglish word (the symbol Fe is derived from Latin ferrum)
27CoCobaltGerman Kobold, 'goblin'
28NiNickelNickel, a mischievous sprite of German miner mythology
29CuCopperEnglish word, from Latin cuprum, from Ancient Greek Kýpros 'Cyprus'
30ZnZincMost likely from German Zinke, 'prong' or 'tooth', though some suggest Persian sang, 'stone'
31GaGalliumLatin Gallia, 'France'
32GeGermaniumLatin Germania, 'Germany'
33AsArsenicFrench arsenic, from Greek arsenikón 'yellow arsenic' (influenced by arsenikós, 'masculine' or 'virile'), from a West Asian wanderword ultimately from Old Iranian *zarniya-ka, 'golden'
34SeSeleniumGreek selḗnē, 'moon'
35BrBromineGreek brômos, 'stench'
36KrKryptonGreek kryptós, 'hidden'
37RbRubidiumLatin rubidus, 'deep red'
38SrStrontiumStrontian, a village in Scotland
39YYttriumYtterby, a village in Sweden
40ZrZirconiumzircon, a mineral
41NbNiobiumNiobe, daughter of king Tantalus from Greek mythology
42MoMolybdenumGreek molýbdaina, 'piece of lead', from mólybdos, 'lead'
43TcTechnetiumGreek tekhnētós, 'artificial'
44RuRutheniumNeo-Latin Ruthenia, 'Russia'
45RhRhodiumGreek rhodóeis, 'rose-coloured', from rhódon, 'rose'
46PdPalladiumthe asteroid Pallas, considered a planet at the time
47AgSilverEnglish word (The symbol derives from Latin argentum)
48CdCadmiumNeo-Latin cadmia, from King Kadmos
49InIndiumLatin indicum, 'indigo' (colour found in its spectrum)
50SnTinEnglish word (The symbol derives from Latin stannum)
51SbAntimonyLatin antimonium, the origin of which is uncertain: folk etymologies suggest it is derived from Greek antí ('against') + mónos ('alone'), or Old French anti-moine, 'Monk's bane', but it could plausibly be from or related to Arabic ʾiṯmid, 'antimony', reformatted as a Latin word. (The symbol derives from Latin stibium 'stibnite'.)
52TeTelluriumLatin tellus, 'the ground, earth'
53IIodineFrench iode, from Greek ioeidḗs, 'violet'
54XeXenonGreek xénon, neuter form of xénos 'strange'
55CsCaesiumLatin caesius, 'sky-blue'
56BaBariumGreek barýs, 'heavy'
57LaLanthanumGreek lanthánein, 'to lie hidden'
58CeCeriumthe dwarf planet Ceres, considered a planet at the time
59PrPraseodymiumGreek prásios dídymos, 'green twin'
60NdNeodymiumGreek néos dídymos, 'new twin'
61PmPromethiumPrometheus of Greek mythology
62SmSamariumsamarskite, a mineral named after Colonel Vasili Samarsky-Bykhovets, Russian mine official
63EuEuropiumEurope
64GdGadoliniumgadolinite, a mineral named after Johan Gadolin, Finnish chemist, physicist and mineralogist
65TbTerbiumYtterby, a village in Sweden
66DyDysprosiumGreek dysprósitos, 'hard to get'
67HoHolmiumNeo-Latin Holmia, 'Stockholm'
68ErErbiumYtterby, a village in Sweden
69TmThuliumThule, the ancient name for an unclear northern location
70YbYtterbiumYtterby, a village in Sweden
71LuLutetiumLatin Lutetia, 'Paris'
72HfHafniumNeo-Latin Hafnia, 'Copenhagen' (from Danish havn)
73TaTantalumKing Tantalus, father of Niobe from Greek mythology
74WTungstenSwedish tung sten, 'heavy stone' (The symbol is from wolfram, the old name of the tungsten mineral wolframite)
75ReRheniumLatin Rhenus, 'the Rhine'
76OsOsmiumGreek osmḗ, 'smell'
77IrIridiumIris, the Greek goddess of the rainbow
78PtPlatinumSpanish platina, 'little silver', from plata 'silver'
79AuGoldEnglish word (The symbol derives from Latin aurum)
80HgMercuryMercury, Roman god of commerce, communication, and luck, known for his speed and mobility (The symbol is from the element's Latin name hydrargyrum, derived from Greek hydrárgyros, 'water-silver')
81TlThalliumGreek thallós, 'green shoot or twig'
82PbLeadEnglish word (The symbol derives from Latin plumbum)
83BiBismuthGerman Wismut, from weiß Masse 'white mass', unless from Arabic
84PoPoloniumLatin Polonia, 'Poland' (the home country of Marie Curie)
85AtAstatineGreek ástatos, 'unstable'
86RnRadonradium
87FrFranciumFrance
88RaRadiumFrench radium, from Latin radius, 'ray'
89AcActiniumGreek aktís, 'ray'
90ThThoriumThor, the Scandinavian god of thunder
91PaProtactiniumproto- (from Greek prôtos, 'first, before') + actinium, which is produced through the radioactive decay of protactinium
92UUraniumUranus, the seventh planet in the Solar System
93NpNeptuniumNeptune, the eighth planet in the Solar System
94PuPlutoniumthe dwarf planet Pluto, considered the ninth planet in the Solar System at the time
95AmAmericiumThe Americas, as the element was first synthesised on the continent, by analogy with europium
96CmCuriumPierre Curie and Marie Curie, French physicists and chemists
97BkBerkeliumBerkeley, California, where the element was first synthesised, by analogy with terbium
98CfCaliforniumCalifornia, where the element was first synthesised
99EsEinsteiniumAlbert Einstein, German physicist
100FmFermiumEnrico Fermi, Italian physicist
101MdMendeleviumDmitri Mendeleev, Russian chemist and inventor who proposed the periodic table
102NoNobeliumAlfred Nobel, Swedish chemist and engineer
103LrLawrenciumErnest O. Lawrence, American physicist
104RfRutherfordiumErnest Rutherford, New Zealand chemist and physicist
105DbDubniumDubna, Russia, where the Joint Institute for Nuclear Research is located
106SgSeaborgiumGlenn T. Seaborg, American chemist
107BhBohriumNiels Bohr, Danish physicist
108HsHassiumNeo-Latin Hassia, 'Hesse' (a state in Germany)
109MtMeitneriumLise Meitner, Austrian physicist
110DsDarmstadtiumDarmstadt, Germany, where the element was first synthesised
111RgRoentgeniumWilhelm Conrad Röntgen, German physicist
112CnCoperniciumNicolaus Copernicus, Polish astronomer
113NhNihoniumJapanese Nihon, 'Japan' (where the element was first synthesised)
114FlFleroviumFlerov Laboratory of Nuclear Reactions, part of JINR, where the element was synthesised; itself named after Georgy Flyorov, Russian physicist
115McMoscoviumMoscow Oblast, Russia, where the element was first synthesised
116LvLivermoriumLawrence Livermore National Laboratory in Livermore, California, which collaborated with JINR on its synthesis
117TsTennessineTennessee, United States
118OgOganessonYuri Oganessian, Russian physicist

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.

SymbolNameAtomicnumberNotesWhy notusedRefs
AArgon18A used for Argon until 1957. Current symbol is Ar.45
AbAlabamine85Discredited claim to discovery of astatine.678
AdAldebaranium70Former name for ytterbium.9
AhAnglohelvetium85Discredited claim to discovery of astatine.1011
AkAlkalinium87Discredited claim to discovery of francium.1213
AmAlabamine85Discredited claim to discovery of astatine. The symbol Am is now used for americium.141516
AnAthenium99Proposed name for einsteinium.17
AoAusonium93Discredited claim to discovery of neptunium.1819
AtAustriacum84Discredited claim to discovery of polonium. The symbol At is now used for astatine.20
AzAzote7Former name for nitrogen.21
BoBohemium93Discredited claim to discovery of neptunium.22
BoBoron5Current symbol is B.23
BvBrevium91Former name for protactinium-234.24
BzBerzelium90Baskerville wrongly believed berzelium was a new element. Was actually thorium.25
CbColumbium41Former name for niobium.262728
ChChromium24Current symbol is Cr.29
ClColumbium41Former name for niobium. The symbol Cl is now used for chlorine.30
CmCatium87Proposed name for francium. The symbol Cm is now used for curium.31
CnCarolinium90Baskerville wrongly believed carolinium to be a new element. Was actually thorium. The symbol Cn is now used for copernicium.32
CpCassiopeium71Former name for lutetium.33
CpCopernicium112Current symbol is Cn.34
CtCeltium72Discredited claim to discovery of hafnium.35
CtCenturium100Proposed name for fermium.36
CyCyclonium61Proposed name for promethium.37
DDidymium59/60Mixture of the elements praseodymium and neodymium. Mosander wrongly believed didymium to be an element.38
DaDavyum43Discredited claim to discovery of technetium.3940
DbDubhium69Eder wrongly believed dubhium to be a new element. Was actually thulium. The symbol Db is now used for dubnium.
DbDubnium104Proposed name for rutherfordium. The symbol and name were instead used for element 105.414243
DcDecipium62Delafontaine wrongly believed decipium to be a new element. Was actually samarium.
DcDvicaesium87Name given by Mendeleev to an as of then undiscovered element. When discovered, francium closely matched the prediction.4445
DeDenebium69Eder wrongly believed denebium to be a new element. Was actually thulium.
DiDidymium59/60Mixture of the elements praseodymium and neodymium. Mosander wrongly believed didymium to be an element.46
DoDor85Discredited claim to discovery of astatine made by Horia Hulubei and Yvette Cauchois.4748
DnDubnadium118Proposed name for oganesson.49
DpDecipium62Delafontaine wrongly believed decipium to be a new element. Was actually samarium.
DsDysprosium66Current symbol is Dy. The symbol Ds is now used for darmstadtium.50
DtDvitellurium84Name given by Mendeleev to an as of then undiscovered element. When discovered, polonium closely matched the prediction.5152
EEinsteinium99Current symbol is Es.53
EErbium68Current symbol is Er.54
EaEkaaluminium31Name given by Mendeleev to an as of then undiscovered element. When discovered, gallium closely matched the prediction.5556
EbEkaboron21Name given by Mendeleev to an as of then undiscovered element. When discovered, scandium closely matched the prediction.575859
EbErebodium42Alexander Pringle wrongly believed erebodium to be a new element. Was likely molybdenum.60
ElEkaaluminium31Name given by Mendeleev to an as of then undiscovered element. When discovered, gallium closely matched the prediction.616263
EmEkamanganese43Name given by Mendeleev to an as of then undiscovered element. When discovered, technetium closely matched the prediction.646566
EmEmanation86Also called "radium emanation", the name was originally given by Friedrich Ernst Dorn in 1900.In 1923, this element officially became radon (the name given at one time to 222Rn, an isotope identified in the decay chain of radium).6768
EmEmanium89Alternate name formerly proposed for actinium.69
EsEkasilicon32Name given by Mendeleev to a then undiscovered element. When discovered, germanium closely matched the prediction.The symbol Es is now used for einsteinium.707172
HsHesperium94Discredited claim to discovery of plutonium. The symbol Hs is now used for hassium.737475
EtEkatantalum91Name given by Mendeleev to an as of then undiscovered element. When discovered, protactinium closely matched the prediction.7677
ExEuxenium72Discredited claim to discovery of hafnium.7879
FaFrancium87Current symbol is Fr.80
FlFlorentium61Discredited claim to discovery of promethium. The symbol Fl is now used for flerovium.81
FlFluorine9Current symbol is F. The symbol Fl is now used for flerovium.82
FrFlorentium61Discredited claim to discovery of promethium. The symbol Fr is now used for francium.8384
GGlucinium4Former name for beryllium.85
GhGhiorsium118Discredited claim to discovery of oganesson.86
GlGlucinium4Former name for beryllium.8788
HaHahnium105Proposed name for dubnium.89
HnHahnium108Proposed name for hassium.9091
HvHelvetium85Discredited claim to discovery of astatine.9293
HyMercury80Hy from the Greek hydrargyrum for "liquid silver". Current symbol is Hg.9495
IIridium77Current symbol is Ir. The symbol I is now used for iodine.96
IcIncognitium65Demarçay wrongly believed incognitium to be a new element. Was actually terbium mixed with gadolinium.97
IlIllinium61Discredited claim to discovery of promethium.9899
IlIlmenium41/73Mixture of the elements niobium and tantalum. R. Hermann wrongly believed ilmenium to be an element.
IoIonium65Demarçay wrongly believed ionium to be a new element. Was actually terbium.
JJodium53Former name for iodine.100
JgJargonium72Discredited claim to discovery of hafnium.101102
JlJoliotium105Proposed name for dubnium.103104
JpJaponium113Proposed name for nihonium.105
KaPotassium19Current symbol is K.106
KuKurchatovium104Proposed name for rutherfordium.107108
LLithium3Current symbol is Li.109
LwLawrencium103Current symbol is Lr.110
MMuriaticum17Former name for chlorine.111
MaManganese25Current symbol is Mn.112
MaMasurium43Disputed claim to discovery of technetium.113114
MdMendelevium97Proposed name for berkelium. The symbol and name were later used for element 101.115116
MlMoldavium87Discredited claim to discovery of francium made by Horia Hulubei and Yvette Cauchois.117118
MsMagnesium12Current symbol is Mg.119
MsMasrium88Discredited claim to discovery of radium.120
MsMasurium43Disputed claim to discovery of technetium.121
MsMosandrium65Smith wrongly believed mosandrium to be a new element. Was actually terbium.
MvMendelevium101Current symbol is Md.122
NgNorwegium72Discredited claim to discovery of hafnium.123
NoNorium72Discredited claim to discovery of hafnium. The symbol No is now used for nobelium.124
NpNeptunium91Discredited claim to discovery of protactinium. The symbol and name were later used for element 93.125126
NpNipponium43Discredited claim to discovery of technetium. The symbol Np is now used for neptunium.127128
NsNielsbohrium105Proposed name for dubnium.129130
NsNielsbohrium107Proposed name for bohrium.131132
NtNiton86Former name for radon.133134
NyNeoytterbium70Former name for ytterbium.135
PLead82Current symbol is Pb. The symbol P is now used for phosphorus.136
PaPalladium46Current symbol is Pd. The symbol Pa is now used for protactinium.137
PePelopium41Former name for niobium.138
PhPhosphorus15Current symbol is P.139
PlPalladium46Current symbol is Pd.140
PmPolymnestum33Alexander Pringle wrongly believed polymnestum to be a new element. Was likely arsenic. The symbol Pm is now used for promethium.141
PoPotassium19Current symbol is K. The symbol Po is now used for polonium.142
PpPhilippium67Delafontaine discovered a new element and named it philippium. Per Teodor Cleve isolated it and renamed it holmium.143
RRhodium45Current symbol is Rh. (The symbol is now sometimes used for an alkyl group.)144
RdRadium88Current symbol is Ra.145
RfRutherfordium106Proposed name for seaborgium. The symbol and name were instead used for element 104.146147148
RoRhodium45Current symbol is Rh.149
SaSamarium62Current symbol is Sm.150151
SoSodium11Current symbol is Na.152
SqSequanium93Discredited claim to discovery of neptunium made by Horia Hulubei and Yvette Cauchois.153154
StAntimony51Current symbol is Sb.155
StTin50Current symbol is Sn.156
TmTrimanganese75Name given by Mendeleev to an as of then undiscovered element. When discovered, rhenium closely matched the prediction. The symbol Tm is now used for thulium.157158
TnTungsten74Current symbol is W.159
TrTerbium65Current symbol is Tb.160
TuThulium69Current symbol is Tm.161
TuTungsten74Current symbol is W.162
UrUralium75Discredited claim to discovery of rhenium.163
UrUranium92Current symbol is U.164
VcVictorium64Crookes wrongly believed victorium to be a new element. Was actually gadolinium.
ViVictorium64Crookes wrongly believed victorium to be a new element. Was actually gadolinium.
ViVirginium87Discredited claim to discovery of francium.165166
VmVirginium87Discredited claim to discovery of francium.167168
VaVanadium23Current symbol is V.169
WoWolfram74Former name for tungsten.170
XXenon54Current symbol is Xe. The symbol X is now used for any halogen.171
YtYttrium39Current symbol is Y.172173

Systematic chemical symbols

These symbols are based on systematic element names, which are now replaced by trivial (non-systematic) element names and symbols. Data is given in order of: atomic number, systematic symbol, systematic name; trivial symbol, trivial name.

When elements beyond oganesson (starting with ununennium, Uue, element 119), are discovered; their systematic name and symbol will presumably be superseded by a trivial name and symbol.

Alchemical symbols

Main article: Alchemical symbols

The following ideographic symbols were used in alchemy to denote elements known since ancient times. Not included in this list are spurious elements, such as the classical elements fire and water or phlogiston, and substances now known to be compounds. Many more symbols were in at least sporadic use: one early 17th-century alchemical manuscript lists 22 symbols for mercury alone.174

Planetary names and symbols for the metals – the seven planets and seven metals known since Classical times in Europe and the Mideast – was ubiquitous in alchemy. The association of what are anachronistically known as planetary metals started breaking down with the discovery of antimony, bismuth and zinc in the 16th century. Alchemists would typically call the metals by their planetary names, e.g. "Saturn" for lead and "Mars" for iron; compounds of tin, iron and silver continued to be called "jovial", "martial" and "lunar"; or "of Jupiter", "of Mars" and "of the moon", through the 17th century. The tradition remains today with the name of the element mercury, where chemists decided the planetary name was preferable to common names like "quicksilver", and in a few archaic terms such as lunar caustic (silver nitrate) and saturnism (lead poisoning).175

Alchemical symbols for the modern elements
SymbolElementAtomicnumberNotes
Phosphorus15(discovered late)
🜍Sulfur16used by Newton
Manganese25late; used by Torbern Bergman (1775)
Iron26classical planetary metal of Mars
🜶Cobalt27late; used by Bergman
Nickel28late; used by Bergman (old positional variant of arsenic, previously used for regulus of sulfur)
Zinc30late; used by Bergman
Copper29classical planetary metal of Venus
🜺Arsenic33
Silver47classical planetary metal of the Moon
🜛
Tin50classical planetary metal of Jupiter
Antimony51the newly discovered "eighth metal" was given the symbol for the Earth, which was recognized as a planet by that time
Platinum78late; used by Bergman et al.: a compound of ☉ gold and ☾ silver
late; symbol invented for the newly discovered planet Uranus so that it could also be used for newly recognized platinum
🜚Gold79classical variant
medieval variant; planetary metal of the Sun
Mercury80classical planetary metal of Mercury
Lead82classical planetary metal of Saturn
Bismuth83used by Newton
♉︎used by Bergman

Daltonian symbols

The following symbols were employed by John Dalton in the early 1800s as the periodic table of elements was being formulated. Not included in this list are substances now known to be compounds, such as certain rare-earth mineral blends. Modern alphabetic notation was introduced in 1814 by Jöns Jakob Berzelius; its precursor can be seen in Dalton's circled letters for the metals, especially in his augmented table from 1810.176 A trace of Dalton's conventions also survives in ball-and-stick models of molecules, where balls for carbon are black and for oxygen red.

Daltonian symbols for the elements
SymbolDalton's nameModern nameAtomicnumberNotesRefs
img.char.
hydrogen1or ⊙177
glucineberyllium4alchemical symbol for 'sugar'178
carbone, carboncarbon6179
azotenitrogen/azote7alchemical symbol for niter180
oxygen8or ◯181
sodasodium11182
magnesiamagnesium12alchemical symbol for magnesia183
aluminealuminium13(4 dots)184
🟕silexsilicon14185
phosphorus15(3 radii)186
🜨sulphur16187
potashpotassium19(3 vertical lines)188
limecalcium20or ◎189
titanium22(enclosing circle) Tit⃝190
manganese25(enclosing circle) Ma⃝191
iron26192
nickel28193
cobalt27(enclosing circle) Cob⃝194
copper29(black letter in red circle)195
zinc30196
arsenic33(enclosing circle) Ar⃝197
strontianstrontium38(4 ticks)198
⊕︀︀yttriayttrium39(plus does not touch circle)199
zirconezirconium40(vertical zigzag)200
silver47201
tin50202
antimony51(enclosing circle) An⃝203
barytesbarium56(6 ticks)204
cerium58(enclosing circle) Ce⃝205
tungsten74(enclosing circle) Tu⃝206
platinaplatinum78(black letter in red circle)207
gold79208
mercury80(dotted inside perimeter)209
lead82210
bismuth83211
uranium92212

Symbols for named isotopes

The following is a list of isotopes which have been given unique symbols. This is not a list of current systematic symbols (in the uAtom form); such a list can instead be found in Template:Navbox element isotopes. The symbols for isotopes of hydrogen, deuterium (D) and tritium (T), are still in use today, as is thoron (Tn) for radon-220 (though not actinon; An usually instead means 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 or C6D6 can be used instead of C6[2H6].213

The symbols for isotopes of elements other than hydrogen and radon are no longer used in the scientific community. Many of these symbols were designated during the early years of radiochemistry, and several isotopes (namely those in the decay chains of actinium, radium, and thorium) bear placeholder names using the early naming system devised by Ernest Rutherford.214

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

Other symbols

See also: Skeletal formula § Pseudoelement symbols

General:

From organic chemistry:

Exotic atoms:

Hazard pictographs are another type of symbols used in chemistry.

See also

Notes

Wikimedia Commons has media related to Chemical symbols.

References

  1. IUPAC Provisional Recommendations: IR-3: Elements and Groups of Elements (PDF) (Report). IUPAC. March 2004. http://old.iupac.org/reports/provisional/abstract04/RB-prs310804/Chap3-3.04.pdf

  2. "Periodic Table – Royal Society of Chemistry". www.rsc.org. https://www.rsc.org/periodic-table

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  14. Name designated by discredited/disputed claimant.

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  16. Biggs, Lindy; Knowlton, Stephen (3 February 2022). "Fred Allison". Encyclopedia of Alabama. http://www.encyclopediaofalabama.org/article/h-1672

  17. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  18. Name designated by discredited/disputed claimant.

  19. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

  20. Name designated by discredited/disputed claimant.

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

  22. Name designated by discredited/disputed claimant.

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

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

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

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

  27. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

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

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

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

  31. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

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

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

  35. Name designated by discredited/disputed claimant.

  36. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  37. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

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

  42. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  43. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

  44. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  45. Temporary placeholder name.

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  47. Name designated by discredited/disputed claimant.

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

  49. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

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

  51. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  52. Temporary placeholder name.

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

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

  55. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  56. Temporary placeholder name.

  57. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  58. Temporary placeholder name.

  59. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

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

  61. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  62. Temporary placeholder name.

  63. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

  64. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  65. Temporary placeholder name.

  66. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

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

  68. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

  69. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  70. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  71. Temporary placeholder name.

  72. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

  73. Name designated by discredited/disputed claimant.

  74. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

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  76. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  77. Temporary placeholder name.

  78. Name designated by discredited/disputed claimant.

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

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

  81. Name designated by discredited/disputed claimant.

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

  83. Name designated by discredited/disputed claimant.

  84. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

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

  86. Name designated by discredited/disputed claimant.

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

  88. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

  89. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  90. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  91. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

  92. Name designated by discredited/disputed claimant.

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

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

  95. Holden, N. E. (12 March 2004). "History of the Origin of the Chemical Elements and Their Discoverers". National Nuclear Data Center. https://www.nndc.bnl.gov/content/elements.html

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

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

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

  101. Name designated by discredited/disputed claimant.

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  103. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

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  105. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

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

  107. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  108. Leal, João P. (2013). "The Forgotten Names of Chemical Elements". Foundations of Science. 19 (2): 175–183. doi:10.1007/s10699-013-9326-y. S2CID 254511660. /wiki/Foundations_of_Science

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

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

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

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

  113. Name designated by discredited/disputed claimant.

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

  116. Name proposed prior to discovery/creation of element or prior to official renaming of a placeholder name.

  117. Name designated by discredited/disputed claimant.

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  120. Name designated by discredited/disputed claimant.

  121. Name designated by discredited/disputed claimant.

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

  123. Name designated by discredited/disputed claimant.

  124. Name designated by discredited/disputed claimant.

  125. Name designated by discredited/disputed claimant.

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

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

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

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

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