# Chemical symbol

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.

## History

Earlier symbols for chemical elements stem from classical Latin and Greek vocabulary. For some elements, this is because the material was known in ancient times, while for others, the name is a more recent invention. For example, 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. 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., $^{14}$N). 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., $^{99m}$Tc). Alternately, the number here can represent a specific spin state (e.g., $^1$O$_2$). 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., $_{64}$Gd). 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 Ca$^{2+}$).
* The number of atoms of an element in a molecule or chemical compound is shown in the right subscript position (e.g., N$_2$ or Fe$_2$O$_3$). 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 :
| Z | Symbol | Name | Origin of name |
| 1 | H | Hydrogen | Greek elements hydro- and -gen, meaning 'water-forming' |
| 2 | He | Helium | Greek hḗlios, 'sun' |
| 3 | Li | Lithium | Greek líthos, 'stone' |
| 4 | Be | Beryllium | beryl, a mineral (ultimately from the name of Belur in southern India) |
| 5 | B | Boron | borax, a mineral (from Arabic bawraq) |
| 6 | C | Carbon | Latin carbo, 'coal' |
| 7 | N | Nitrogen | Greek nítron and -gen, meaning 'niter-forming' |
| 8 | O | Oxygen | Greek oxy- and -gen, meaning 'acid-forming' |
| 9 | F | Fluorine | Latin fluere, 'to flow' |
| 10 | Ne | Neon | Greek néon, 'new' |
| 11 | Na | Sodium | English soda (the symbol Na is derived from Neo-Latin natrium, coined from German Natron, 'natron') |
| 12 | Mg | Magnesium | Magnesia, a district of Eastern Thessaly in Greece |
| 13 | Al | Aluminium | alumina, from Latin alumen (gen. alumni), 'bitter salt, alum' |
| 14 | Si | Silicon | Latin silex, 'flint' (originally silicium) |
| 15 | P | Phosphorus | Greek phōsphóros, 'light-bearing' |
| 16 | S | Sulfur | Latin sulphur, 'brimstone' |
| 17 | Cl | Chlorine | Greek chlōrós, 'greenish yellow' |
| 18 | Ar | Argon | Greek argós, 'idle' (because of its inertness) |
| 19 | K | Potassium | Neo-Latin potassa, 'potash' (the symbol K is derived from Latin kalium) |
| 20 | Ca | Calcium | Latin calx, 'lime' |
| 21 | Sc | Scandium | Latin Scandia, 'Scandinavia' |
| 22 | Ti | Titanium | Titans, the sons of the Earth goddess of Greek mythology |
| 23 | V | Vanadium | Vanadis, an Old Norse name for the Scandinavian goddess Freyja |
| 24 | Cr | Chromium | Greek chróma, 'colour' |
| 25 | Mn | Manganese | corrupted from magnesia negra; see Magnesium |
| 26 | Fe | Iron | English word (the symbol Fe is derived from Latin ferrum) |
| 27 | Co | Cobalt | German Kobold, 'goblin' |
| 28 | Ni | Nickel | Nickel, a mischievous sprite of German miner mythology |
| 29 | Cu | Copper | English word, from Latin cuprum, from Ancient Greek Kýpros 'Cyprus' |
| 30 | Zn | Zinc | Most likely from German Zinke, 'prong' or 'tooth', though some suggest Persian sang, 'stone' |
| 31 | Ga | Gallium | Latin Gallia, 'France' |
| 32 | Ge | Germanium | Latin Germania, 'Germany' |
| 33 | As | Arsenic | French arsenic, from Greek arsenikón 'yellow arsenic' (influenced by arsenikós, 'masculine' or 'virile'), from a West Asian wanderword ultimately from Old Iranian *zarniya-ka, 'golden' |
| 34 | Se | Selenium | Greek selḗnē, 'moon' |
| 35 | Br | Bromine | Greek brômos, 'stench' |
| 36 | Kr | Krypton | Greek kryptós, 'hidden' |
| 37 | Rb | Rubidium | Latin rubidus, 'deep red' |
| 38 | Sr | Strontium | Strontian, a village in Scotland |
| 39 | Y | Yttrium | Ytterby, a village in Sweden |
| 40 | Zr | Zirconium | zircon, a mineral |
| 41 | Nb | Niobium | Niobe, daughter of king Tantalus from Greek mythology |
| 42 | Mo | Molybdenum | Greek molýbdaina, 'piece of lead', from mólybdos, 'lead' |
| 43 | Tc | Technetium | Greek tekhnētós, 'artificial' |
| 44 | Ru | Ruthenium | Neo-Latin Ruthenia, 'Russia' |
| 45 | Rh | Rhodium | Greek rhodóeis, 'rose-coloured', from rhódon, 'rose' |
| 46 | Pd | Palladium | the asteroid Pallas, considered a planet at the time |
| 47 | Ag | Silver | English word (The symbol derives from Latin argentum) |
| 48 | Cd | Cadmium | Neo-Latin cadmia, from King Kadmos |
| 49 | In | Indium | Latin indicum, 'indigo' (colour found in its spectrum) |
| 50 | Sn | Tin | English word (The symbol derives from Latin stannum) |
| 51 | Sb | Antimony | Latin 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'.) |
| 52 | Te | Tellurium | Latin tellus, 'the ground, earth' |
| 53 | I | Iodine | French iode, from Greek ioeidḗs, 'violet' |
| 54 | Xe | Xenon | Greek xénon, neuter form of xénos 'strange' |
| 55 | Cs | Caesium | Latin caesius, 'sky-blue' |
| 56 | Ba | Barium | Greek barýs, 'heavy' |
| 57 | La | Lanthanum | Greek lanthánein, 'to lie hidden' |
| 58 | Ce | Cerium | the dwarf planet Ceres, considered a planet at the time |
| 59 | Pr | Praseodymium | Greek prásios dídymos, 'green twin' |
| 60 | Nd | Neodymium | Greek néos dídymos, 'new twin' |
| 61 | Pm | Promethium | Prometheus of Greek mythology |
| 62 | Sm | Samarium | samarskite, a mineral named after Colonel Vasili Samarsky-Bykhovets, Russian mine official |
| 63 | Eu | Europium | Europe |
| 64 | Gd | Gadolinium | gadolinite, a mineral named after Johan Gadolin, Finnish chemist, physicist and mineralogist |
| 65 | Tb | Terbium | Ytterby, a village in Sweden |
| 66 | Dy | Dysprosium | Greek dysprósitos, 'hard to get' |
| 67 | Ho | Holmium | Neo-Latin Holmia, 'Stockholm' |
| 68 | Er | Erbium | Ytterby, a village in Sweden |
| 69 | Tm | Thulium | Thule, the ancient name for an unclear northern location |
| 70 | Yb | Ytterbium | Ytterby, a village in Sweden |
| 71 | Lu | Lutetium | Latin Lutetia, 'Paris' |
| 72 | Hf | Hafnium | Neo-Latin Hafnia, 'Copenhagen' (from Danish havn) |
| 73 | Ta | Tantalum | King Tantalus, father of Niobe from Greek mythology |
| 74 | W | Tungsten | Swedish tung sten, 'heavy stone' (The symbol is from wolfram, the old name of the tungsten mineral wolframite) |
| 75 | Re | Rhenium | Latin Rhenus, 'the Rhine' |
| 76 | Os | Osmium | Greek osmḗ, 'smell' |
| 77 | Ir | Iridium | Iris, the Greek goddess of the rainbow |
| 78 | Pt | Platinum | Spanish platina, 'little silver', from plata 'silver' |
| 79 | Au | Gold | English word (The symbol derives from Latin aurum) |
| 80 | Hg | Mercury | Mercury, 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') |
| 81 | Tl | Thallium | Greek thallós, 'green shoot or twig' |
| 82 | Pb | Lead | English word (The symbol derives from Latin plumbum) |
| 83 | Bi | Bismuth | German Wismut, from weiß Masse 'white mass', unless from Arabic |
| 84 | Po | Polonium | Latin Polonia, 'Poland' (the home country of Marie Curie) |
| 85 | At | Astatine | Greek ástatos, 'unstable' |
| 86 | Rn | Radon | radium |
| 87 | Fr | Francium | France |
| 88 | Ra | Radium | French radium, from Latin radius, 'ray' |
| 89 | Ac | Actinium | Greek aktís, 'ray' |
| 90 | Th | Thorium | Thor, the Scandinavian god of thunder |
| 91 | Pa | Protactinium | proto- (from Greek prôtos, 'first, before') + actinium, which is produced through the radioactive decay of protactinium |
| 92 | U | Uranium | Uranus, the seventh planet in the Solar System |
| 93 | Np | Neptunium | Neptune, the eighth planet in the Solar System |
| 94 | Pu | Plutonium | the dwarf planet Pluto, considered the ninth planet in the Solar System at the time |
| 95 | Am | Americium | The Americas, as the element was first synthesised on the continent, by analogy with europium |
| 96 | Cm | Curium | Pierre Curie and Marie Curie, French physicists and chemists |
| 97 | Bk | Berkelium | Berkeley, California, where the element was first synthesised, by analogy with terbium |
| 98 | Cf | Californium | California, where the element was first synthesised |
| 99 | Es | Einsteinium | Albert Einstein, German physicist |
| 100 | Fm | Fermium | Enrico Fermi, Italian physicist |
| 101 | Md | Mendelevium | Dmitri Mendeleev, Russian chemist and inventor who proposed the periodic table |
| 102 | No | Nobelium | Alfred Nobel, Swedish chemist and engineer |
| 103 | Lr | Lawrencium | Ernest O. Lawrence, American physicist |
| 104 | Rf | Rutherfordium | Ernest Rutherford, New Zealand chemist and physicist |
| 105 | Db | Dubnium | Dubna, Russia, where the Joint Institute for Nuclear Research is located |
| 106 | Sg | Seaborgium | Glenn T. Seaborg, American chemist |
| 107 | Bh | Bohrium | Niels Bohr, Danish physicist |
| 108 | Hs | Hassium | Neo-Latin Hassia, 'Hesse' (a state in Germany) |
| 109 | Mt | Meitnerium | Lise Meitner, Austrian physicist |
| 110 | Ds | Darmstadtium | Darmstadt, Germany, where the element was first synthesised |
| 111 | Rg | Roentgenium | Wilhelm Conrad Röntgen, German physicist |
| 112 | Cn | Copernicium | Nicolaus Copernicus, Polish astronomer |
| 113 | Nh | Nihonium | Japanese Nihon, 'Japan' (where the element was first synthesised) |
| 114 | Fl | Flerovium | Flerov Laboratory of Nuclear Reactions, part of JINR, where the element was synthesised; itself named after Georgy Flyorov, Russian physicist |
| 115 | Mc | Moscovium | Moscow Oblast, Russia, where the element was first synthesised |
| 116 | Lv | Livermorium | Lawrence Livermore National Laboratory in Livermore, California, which collaborated with JINR on its synthesis |
| 117 | Ts | Tennessine | Tennessee, United States |
| 118 | Og | Oganesson | Yuri 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.
| Symbol | Name | Atomic number | Notes |
| A | Argon | 18 | A used for Argon until 1957. Current symbol is Ar. |
| Ab | Alabamine | 85 | Discredited claim to discovery of astatine. |
| Ad | Aldebaranium | 70 | Former name for ytterbium. |
| Ah | Anglohelvetium | 85 | Discredited claim to discovery of astatine. |
| Ak | Alkalinium | 87 | Discredited claim to discovery of francium. |
| Am | Alabamine | 85 | Discredited claim to discovery of astatine. The symbol Am is now used for americium. |
| An | Athenium | 99 | Proposed name for einsteinium. |
| Ao | Ausonium | 93 | Discredited claim to discovery of neptunium. |
| At | Austriacum | 84 | Discredited claim to discovery of polonium. The symbol At is now used for astatine. |
| Az | Azote | 7 | Former name for nitrogen. |
| Bo | Bohemium | 93 | Discredited claim to discovery of neptunium. |
| Bo | Boron | 5 | Current symbol is B. |
| Bv | Brevium | 91 | Former name for protactinium-234. |
| Bz | Berzelium | 90 | Baskerville wrongly believed berzelium was a new element. Was actually thorium. |
| Cb | Columbium | 41 | Former name for niobium. |
| Ch | Chromium | 24 | Current symbol is Cr. |
| Cl | Columbium | 41 | Former name for niobium. The symbol Cl is now used for chlorine. |
| Cm | Catium | 87 | Proposed name for francium. The symbol Cm is now used for curium. |
| Cn | Carolinium | 90 | Baskerville wrongly believed carolinium to be a new element. Was actually thorium. The symbol Cn is now used for copernicium. |
| Cp | Cassiopeium | 71 | Former name for lutetium. |
| Cp | Copernicium | 112 | Current symbol is Cn. |
| Ct | Celtium | 72 | Discredited claim to discovery of hafnium. |
| Ct | Centurium | 100 | Proposed name for fermium. |
| Cy | Cyclonium | 61 | Proposed name for promethium. |
| D | Didymium | 59/60 | Mixture of the elements praseodymium and neodymium. Mosander wrongly believed didymium to be an element. |
| Da | Davyum | 43 | Discredited claim to discovery of technetium. |
| Db | Dubhium | 69 | Eder wrongly believed dubhium to be a new element. Was actually thulium. The symbol Db is now used for dubnium. |
| Db | Dubnium | 104 | Proposed name for rutherfordium. The symbol and name were instead used for element 105. |
| Dc | Decipium | 62 | Delafontaine wrongly believed decipium to be a new element. Was actually samarium. |
| Dc | Dvicaesium | 87 | Name given by Mendeleev to an as of then undiscovered element. When discovered, francium closely matched the prediction. |
| De | Denebium | 69 | Eder wrongly believed denebium to be a new element. Was actually thulium. |
| Di | Didymium | 59/60 | Mixture of the elements praseodymium and neodymium. Mosander wrongly believed didymium to be an element. |
| Do | Dor | 85 | Discredited claim to discovery of astatine made by Horia Hulubei and Yvette Cauchois. |
| Dn | Dubnadium | 118 | Proposed name for oganesson. |
| Dp | Decipium | 62 | Delafontaine wrongly believed decipium to be a new element. Was actually samarium. |
| Ds | Dysprosium | 66 | Current symbol is Dy. The symbol Ds is now used for darmstadtium. |
| Dt | Dvitellurium | 84 | Name given by Mendeleev to an as of then undiscovered element. When discovered, polonium closely matched the prediction. |
| E | Einsteinium | 99 | Current symbol is Es. |
| E | Erbium | 68 | Current symbol is Er. |
| Ea | Ekaaluminium | 31 | Name given by Mendeleev to an as of then undiscovered element. When discovered, gallium closely matched the prediction. |
| Eb | Ekaboron | 21 | Name given by Mendeleev to an as of then undiscovered element. When discovered, scandium closely matched the prediction. |
| Eb | Erebodium | 42 | Alexander Pringle wrongly believed erebodium to be a new element. Was likely molybdenum. |
| El | Ekaaluminium | 31 | Name given by Mendeleev to an as of then undiscovered element. When discovered, gallium closely matched the prediction. |
| Em | Ekamanganese | 43 | Name given by Mendeleev to an as of then undiscovered element. When discovered, technetium closely matched the prediction. |
| 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 $^{222}$Rn, an isotope identified in the decay chain of radium). |
| Em | Emanium | 89 | Alternate name formerly proposed for actinium. |
| Es | Ekasilicon | 32 | Name given by Mendeleev to a then undiscovered element. When discovered, germanium closely matched the prediction. The symbol Es is now used for einsteinium. |
| Hs | Hesperium | 94 | Discredited claim to discovery of plutonium. The symbol Hs is now used for hassium. |
| Et | Ekatantalum | 91 | Name given by Mendeleev to an as of then undiscovered element. When discovered, protactinium closely matched the prediction. |
| Ex | Euxenium | 72 | Discredited claim to discovery of hafnium. |
| Fa | Francium | 87 | Current symbol is Fr. |
| Fl | Florentium | 61 | Discredited claim to discovery of promethium. The symbol Fl is now used for flerovium. |
| Fl | Fluorine | 9 | Current symbol is F. The symbol Fl is now used for flerovium. |
| Fr | Florentium | 61 | Discredited claim to discovery of promethium. The symbol Fr is now used for francium. |
| G | Glucinium | 4 | Former name for beryllium. |
| Gh | Ghiorsium | 118 | Discredited claim to discovery of oganesson. |
| Gl | Glucinium | 4 | Former name for beryllium. |
| Ha | Hahnium | 105 | Proposed name for dubnium. |
| Hn | Hahnium | 108 | Proposed name for hassium. |
| Hv | Helvetium | 85 | Discredited claim to discovery of astatine. |
| Hy | Mercury | 80 | Hy from the Greek hydrargyrum for "liquid silver". Current symbol is Hg. |
| I | Iridium | 77 | Current symbol is Ir. The symbol I is now used for iodine. |
| Ic | Incognitium | 65 | Demarçay wrongly believed incognitium to be a new element. Was actually terbium mixed with gadolinium. |
| Il | Illinium | 61 | Discredited claim to discovery of promethium. |
| Il | Ilmenium | 41/73 | Mixture of the elements niobium and tantalum. R. Hermann wrongly believed ilmenium to be an element. |
| Io | Ionium | 65 | Demarçay wrongly believed ionium to be a new element. Was actually terbium. |
| J | Jodium | 53 | Former name for iodine. |
| Jg | Jargonium | 72 | Discredited claim to discovery of hafnium. |
| Jl | Joliotium | 105 | Proposed name for dubnium. |
| Jp | Japonium | 113 | Proposed name for nihonium. |
| Ka | Potassium | 19 | Current symbol is K. |
| Ku | Kurchatovium | 104 | Proposed name for rutherfordium. |
| L | Lithium | 3 | Current symbol is Li. |
| Lw | Lawrencium | 103 | Current symbol is Lr. |
| M | Muriaticum | 17 | Former name for chlorine. |
| Ma | Manganese | 25 | Current symbol is Mn. |
| Ma | Masurium | 43 | Disputed claim to discovery of technetium. |
| Md | Mendelevium | 97 | Proposed name for berkelium. The symbol and name were later used for element 101. |
| Ml | Moldavium | 87 | Discredited claim to discovery of francium made by Horia Hulubei and Yvette Cauchois. |
| Ms | Magnesium | 12 | Current symbol is Mg. |
| Ms | Masrium | 88 | Discredited claim to discovery of radium. |
| Ms | Masurium | 43 | Disputed claim to discovery of technetium. |
| Ms | Mosandrium | 65 | Smith wrongly believed mosandrium to be a new element. Was actually terbium. |
| Mv | Mendelevium | 101 | Current symbol is Md. |
| Ng | Norwegium | 72 | Discredited claim to discovery of hafnium. |
| No | Norium | 72 | Discredited claim to discovery of hafnium. The symbol No is now used for nobelium. |
| Np | Neptunium | 91 | Discredited claim to discovery of protactinium. The symbol and name were later used for element 93. |
| Np | Nipponium | 43 | Discredited claim to discovery of technetium. The symbol Np is now used for neptunium. |
| Ns | Nielsbohrium | 105 | Proposed name for dubnium. |
| Ns | Nielsbohrium | 107 | Proposed name for bohrium. |
| Nt | Niton | 86 | Former name for radon. |
| Ny | Neoytterbium | 70 | Former name for ytterbium. |
| P | Lead | 82 | Current symbol is Pb. The symbol P is now used for phosphorus. |
| Pa | Palladium | 46 | Current symbol is Pd. The symbol Pa is now used for protactinium. |
| Pe | Pelopium | 41 | Former name for niobium. |
| Ph | Phosphorus | 15 | Current symbol is P. |
| Pl | Palladium | 46 | Current symbol is Pd. |
| Pm | Polymnestum | 33 | Alexander Pringle wrongly believed polymnestum to be a new element. Was likely arsenic. The symbol Pm is now used for promethium. |
| Po | Potassium | 19 | Current symbol is K. The symbol Po is now used for polonium. |
| Pp | Philippium | 67 | Delafontaine discovered a new element and named it philippium. Per Teodor Cleve isolated it and renamed it holmium. |
| R | Rhodium | 45 | Current symbol is Rh. (The symbol is now sometimes used for an alkyl group.) |
| Rd | Radium | 88 | Current symbol is Ra. |
| Rf | Rutherfordium | 106 | Proposed name for seaborgium. The symbol and name were instead used for element 104. |
| Ro | Rhodium | 45 | Current symbol is Rh. |
| Sa | Samarium | 62 | Current symbol is Sm. |
| So | Sodium | 11 | Current symbol is Na. |
| Sq | Sequanium | 93 | Discredited claim to discovery of neptunium made by Horia Hulubei and Yvette Cauchois. |
| St | Antimony | 51 | Current symbol is Sb. |
| St | Tin | 50 | Current symbol is Sn. |
| Tm | Trimanganese | 75 | Name 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. |
| Tn | Tungsten | 74 | Current symbol is W. |
| Tr | Terbium | 65 | Current symbol is Tb. |
| Tu | Thulium | 69 | Current symbol is Tm. |
| Tu | Tungsten | 74 | Current symbol is W. |
| Ur | Uralium | 75 | Discredited claim to discovery of rhenium. |
| Ur | Uranium | 92 | Current symbol is U. |
| Vc | Victorium | 64 | Crookes wrongly believed victorium to be a new element. Was actually gadolinium. |
| Vi | Victorium | 64 | Crookes wrongly believed victorium to be a new element. Was actually gadolinium. |
| Vi | Virginium | 87 | Discredited claim to discovery of francium. |
| Vm | Virginium | 87 | Discredited claim to discovery of francium. |
| Va | Vanadium | 23 | Current symbol is V. |
| Wo | Wolfram | 74 | Former name for tungsten. |
| X | Xenon | 54 | Current symbol is Xe. The symbol X is now used for any halogen. |
| Yt | Yttrium | 39 | Current symbol is Y. |

### 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.
* 101: Unu, unnilunium; Md, mendelevium.
* 102: Unb, unnilbium; No, nobelium.
* 103: Unt, unniltrium; Lr, lawrencium.
* 104: Unq, unnilquadium; Rf, rutherfordium.
* 105: Unp, unnilpentium; Db, dubnium.
* 106: Unh, unnilhexium; Sg, seaborgium.
* 107: Uns, unnilseptium; Bh, bohrium.
* 108: Uno, unniloctium; Hs, hassium.
* 109: Une, unnilennium; Mt, meitnerium.
* 110: Uun, ununnilium; Ds, darmstadtium.
* 111: Uuu, unununium; Rg, roentgenium.
* 112: Uub, ununbium; Cn, copernicium.
* 113: Uut, ununtrium; Nh, nihonium.
* 114: Uuq, ununquadium; Fl, flerovium.
* 115: Uup, ununpentium; Mc, moscovium.
* 116: Uuh, ununhexium; Lv, livermorium.
* 117: Uus, ununseptium; Ts, tennessine.
* 118: Uuo, ununoctium; Og, oganesson.
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

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.
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).
Alchemical symbols for the modern elements :
| Symbol | Element | Atomic number | Notes |
| | Phosphorus | 15 | (discovered late) |
| 🜍 | Sulfur | 16 | used by Newton |
| | Manganese | 25 | late; used by Torbern Bergman (1775) |
| ♂ | Iron | 26 | classical planetary metal of Mars |
| 🜶 | Cobalt | 27 | late; used by Bergman |
| | Nickel | 28 | late; used by Bergman (old positional variant of arsenic, previously used for regulus of sulfur) |
| | Zinc | 30 | late; used by Bergman |
| ♀ | Copper | 29 | classical planetary metal of Venus |
| 🜺 | Arsenic | 33 |
| ☾ | Silver | 47 | classical planetary metal of the Moon |
| 🜛 | Silver | 47 | |
| ♃ | Tin | 50 | classical planetary metal of Jupiter |
| ♁ | Antimony | 51 | the newly discovered "eighth metal" was given the symbol for the Earth, which was recognized as a planet by that time |
| | Platinum | 78 | late; used by Bergman et al.: a compound of ☉ gold and ☾ silver |
| ⛢ | Platinum | 78 | late; symbol invented for the newly discovered planet Uranus so that it could also be used for newly recognized platinum |
| 🜚 | Gold | 79 | classical variant |
| ☉ | Gold | 79 | medieval variant; planetary metal of the Sun |
| ☿ | Mercury | 80 | classical planetary metal of Mercury |
| ♄ | Lead | 82 | classical planetary metal of Saturn |
| ♆ | Bismuth | 83 | used by Newton |
| ♉︎ | Bismuth | 83 | 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. 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 :
| Symbol | Symbol | Dalton's name | Modern name | Atomic number | Notes | Refs |
| img. | char. | Dalton's name | Modern name | Atomic number | Notes | Refs |
| | ☉ | hydrogen | hydrogen | 1 | or ⊙ | |
| | | glucine | beryllium | 4 | alchemical symbol for 'sugar' | |
| | ● | carbone, carbon | carbon | 6 | | |
| | ⦶ | azote | nitrogen/azote | 7 | alchemical symbol for niter | |
| | ○ | oxygen | oxygen | 8 | or ◯ | |
| | ⦷ | soda | sodium | 11 | | |
| | ⊛ | magnesia | magnesium | 12 | alchemical symbol for magnesia | |
| | | alumine | aluminium | 13 | (4 dots) | |
| | 🟕 | silex | silicon | 14 | | |
| | | phosphorus | phosphorus | 15 | (3 radii) | |
| | 🜨 | sulphur | sulphur | 16 | | |
| | | potash | potassium | 19 | (3 vertical lines) | |
| | ⦾ | lime | calcium | 20 | or ◎ | |
| | | titanium | titanium | 22 | (enclosing circle) Tit⃝ | |
| | | manganese | manganese | 25 | (enclosing circle) Ma⃝ | |
| | Ⓘ | iron | iron | 26 | | |
| | Ⓝ | nickel | nickel | 28 | | |
| | | cobalt | cobalt | 27 | (enclosing circle) Cob⃝ | |
| | Ⓒ | copper | copper | 29 | (black letter in red circle) | |
| | Ⓩ | zinc | zinc | 30 | | |
| | | arsenic | arsenic | 33 | (enclosing circle) Ar⃝ | |
| | | strontian | strontium | 38 | (4 ticks) | |
| | ⊕︀︀ | yttria | yttrium | 39 | (plus does not touch circle) | |
| | | zircone | zirconium | 40 | (vertical zigzag) | |
| | Ⓢ | silver | silver | 47 | | |
| | Ⓣ | tin | tin | 50 | | |
| | | antimony | antimony | 51 | (enclosing circle) An⃝ | |
| | | barytes | barium | 56 | (6 ticks) | |
| | | cerium | cerium | 58 | (enclosing circle) Ce⃝ | |
| | | tungsten | tungsten | 74 | (enclosing circle) Tu⃝ | |
| | Ⓟ | platina | platinum | 78 | (black letter in red circle) | |
| | Ⓖ | gold | gold | 79 | | |
| | | mercury | mercury | 80 | (dotted inside perimeter) | |
| | Ⓛ | lead | lead | 82 | | |
| | Ⓑ | bismuth | bismuth | 83 | | |
| | Ⓤ | uranium | uranium | 92 | | |

## 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 $^u$Atom 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, d$_6$-benzene or C$_6$D$_6$ can be used instead of C$_6$[$^2$H$_6$].
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.
| Symbol | Name | Atomic number | Origin of symbol |
| Ac | Actinium | 89 | From Greek aktinos. Name restricted at one time to $^{227}$Ac, 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 $^{215}$Po, 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 $^{211}$Pb, 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 $^{211}$Bi, 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 $^{211}$Po, 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 $^{207}$Tl, an isotope of thallium identified in the decay chain of actinium. |
| AcK | Actinium K | 87 | Name given at one time to $^{223}$Fr, an isotope of francium identified in the decay chain of actinium. |
| AcU | Actino-uranium | 92 | Name given at one time to $^{235}$U, an isotope of uranium. |
| AcX | Actinium X | 88 | Name given at one time to $^{223}$Ra, an isotope of radium identified in the decay chain of actinium. |
| An | Actinon | 86 | From actinium and emanation. Name given at one time to $^{219}$Rn, an isotope of radon identified in the decay chain of actinium. |
| D | Deuterium | 1 | From the Greek deuteros. Name given to $^2$H. |
| Io | Ionium | 90 | Name given to $^{230}$Th, an isotope of thorium identified in the decay chain of uranium. |
| MsTh$_1$ | Mesothorium 1 | 88 | Name given at one time to $^{228}$Ra, an isotope of radium. |
| MsTh$_2$ | Mesothorium 2 | 89 | Name given at one time to $^{228}$Ac, an isotope of actinium. |
| Pa | Protactinium | 91 | From the Greek protos and actinium. Name restricted at one time to $^{231}$Pa, 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 $^{226}$Ra, 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 $^{218}$Po, 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 $^{214}$Pb, 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 $^{214}$Bi, 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 $^{214}$Po, 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 $^{210}$Tl, 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 $^{210}$Pb, 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 $^{210}$Bi, 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 $^{206}$Tl, 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 $^{210}$Po, an isotope of polonium identified in the decay chain of radium. |
| RdAc | Radioactinium | 90 | Name given at one time to $^{227}$Th, an isotope of thorium. |
| RdTh | Radiothorium | 90 | Name given at one time to $^{228}$Th, an isotope of thorium. |
| Rn | Radon | 86 | From radium and emanation. Name restricted at one time to $^{222}$Rn, 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 $^3$H. |
| Th | Thorium | 90 | After Thor. Name restricted at one time to $^{232}$Th, 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 $^{216}$Po, 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 $^{212}$Pb, 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 $^{212}$Bi, 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 $^{212}$Po, 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 $^{208}$Tl, an isotope of thallium identified in the decay chain of thorium. |
| ThX | Thorium X | 88 | Name given at one time to $^{224}$Ra, an isotope of radium identified in the decay chain of thorium. |
| Tn | Thoron | 86 | From thorium and emanation. Name given to $^{220}$Rn, an isotope of radon identified in the decay chain of thorium. |
| UI | Uranium I | 92 | Name given at one time to $^{238}$U, an isotope of uranium. |
| UII | Uranium II | 92 | Name given at one time to $^{234}$U, an isotope of uranium. |
| UX$_1$ | Uranium X$_1$ | 90 | Name given at one time to $^{234}$Th, an isotope of thorium identified in the decay chain of uranium. |
| UX$_2$ | Uranium X$_2$ | 91 | Name given at one time to $^{234m}$Pa, an isotope of protactinium identified in the decay chain of uranium. |
| UY | Uranium Y | 90 | Name given at one time to $^{231}$Th, an isotope of thorium identified in the decay chain of uranium. |
| UZ | Uranium Z | 91 | Name given at one time to $^{234}$Pa, an isotope of protactinium identified in the decay chain of uranium. |

## Other symbols

* In Chinese, each chemical element has a dedicated character, usually created for the purpose (see Chemical elements in East Asian languages). However, in Chinese Latin symbols are also used, especially in formulas.
General:
* A: A deprotonated acid or an anion
* An: any actinide
* B: A base, often in the context of Lewis acid–base theory or Brønsted–Lowry acid–base theory
* E: any element or electrophile
* L: any ligand
* Ln: any lanthanide
* M: any metal
* Mm: mischmetal (occasionally used)
* Ng: any noble gas (Rg is sometimes used, but that is also used for the element roentgenium: see above)
* Nu: any nucleophile
* R: any unspecified radical (moiety) not important to the discussion
* St: steel (occasionally used)
* X: any halogen (or sometimes pseudohalogen)
From organic chemistry:
* Ac: acetyl – (also used for the element actinium: see above)
* Ad: 1-adamantyl
* All: allyl
* Am: amyl (pentyl) – (also used for the element americium: see above)
* Ar: aryl – (also used for the element argon: see above)
* Bn: benzyl
* Bs: brosyl or (outdated) benzenesulfonyl
* Bu: butyl (i-, s-, or t- prefixes may be used to denote iso-, sec-, or tert- isomers, respectively)
* Bz: benzoyl
* Cp: cyclopentadienyl
* Cp*: pentamethylcyclopentadienyl
* Cy: cyclohexyl
* Cyp: cyclopentyl
* Et: ethyl
* Me: methyl
* Mes: mesityl (2,4,6-trimethylphenyl)
* Ms: mesyl (methylsulfonyl)
* Np: neopentyl – (also used for the element neptunium: see above)
* Ns: nosyl
* Pent: pentyl
* Ph, Φ: phenyl
* Pr: propyl – (i- prefix may be used to denote isopropyl. Also used for the element praseodymium: see above)
* R: In organic chemistry contexts, an unspecified "R" is often understood to be an alkyl group
* Tf: triflyl (trifluoromethanesulfonyl)
* Tr, Trt: trityl (triphenylmethyl)
* Ts, Tos: tosyl (para-toluenesulfonyl) – (Ts also used for the element tennessine: see above)
* Vi: vinyl
Exotic atoms:
* Mu: muonium
* Pn: protonium
* Ps: positronium
Hazard pictographs are another type of symbols used in chemistry.