Symbol (chemistry)

In relation to the chemical elements, a symbol is a code for a chemical element. Symbols for chemical elements normally consist of one or two letters from the Latin alphabet and are written with the first letter capitalised. (Many functional groups have their own chemical symbol, e.g. Ph for the phenyl group, and Me for the methyl group.)Notes In relation to the chemical elements, a symbol is a code for a chemical element. Symbols for chemical elements normally consist of one or two letters from the Latin alphabet and are written with the first letter capitalised. (Many functional groups have their own chemical symbol, e.g. Ph for the phenyl group, and Me for the methyl group.) 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 new 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 3-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 its atomic number being 8 greater than 100. There are also some historical symbols that are no longer officially used. In addition to the letter(s) 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.