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 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. 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 elementsZSymbolNameOrigin of name 1 H Hydrogen Greek 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, ultimately from Proto-Celtic *īsarnom, a word related to the Celtic word for "blood" (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, ultimately from Proto-Germanic *silubrą (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, ultimately from Proto-Germanic *tiną, perhaps meaning "shining" (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, ultimately from Proto-Indo-European *ǵʰl̥h₃tóm, related to "yellow" (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, from Proto-Celtic *ɸloudom, from Proto-Indo-European *plewd-, “flow” (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.