Symbol (chemistry)


Chemical symbols are the abbreviations used in for s, s and chemical compounds. Element symbols for chemical elements normally consist of one or two letters from the and are written with the first letter capitalised. In , each chemical element has a dedicated , usually created for the purpose (see ). However, Latin symbols are also used, especially in formulas. Earlier symbols for chemical elements stem from classical and 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 (''plumbum'' in Latin); Hg is the symbol for (''hydrargyrum'' in Greek); and He is the symbol for (a name) because helium was not known in times. Some symbols come from other sources, like W for (''Wolfram'' in German) which was not known in Roman times. A three-letter may be assigned to a newly synthesized (or not yet synthesized) element. For example, "Uno" was the temporary symbol for (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. In addition to the letters for the element itself, additional details may be added to the symbol as a particular , , or , 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 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 (e.g., ). Alternately, the number here can represent a specific (e.g., ). These details can be omitted if not relevant in a certain context. *The proton 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 or an may be indicated in the right superscript position (e.g., state of ionization Ca2+). *The number of atoms of an element in a or 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 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 s. Many s also have their own chemical symbol, e.g. Ph for the , and Me for the . A list of current, dated, as well as proposed and historical signs and symbols is included here with its . Also given is each element's , , or the of the most stable , group and period numbers on the , and of the symbol. are another type of symbols used in chemistry.

Symbols for chemical elements


Antimatter atoms are denoted by a bar above the symbol for their matter counterpart, so e.g. H is the symbol for .

Symbols and names not currently used

The following is a list of symbols and names formerly used or suggested for elements, including symbols for s and names given by discredited claimants for discovery.

Alchemical symbols

The were employed in to symbolize elements known since ancient times. Not included in this list are spurious elements, such as the s and , 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 s 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 (silver nitrate) and (lead poisoning).Maurice Crosland (2004) ''Historical Studies in the Language of Chemistry''

Daltonian symbols

The following symbols were employed by 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 mineral blends. Modern alphabetic notation was introduced in 1814 by ; 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 s of molecules, where balls for carbon are black and for oxygen red.

Symbols for named isotopes

The following is a of elements given in the previous tables which have been designated unique symbols. By this it is meant that a comprehensive list of current systematic symbols (in the uAtom form) is not included in the list and can instead be found in the chart. The symbols for the named , (D), and (T) are still in use today, as is (Tn) for radon-220 (though not ; An is usually used instead for a generic ). and other s 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 and C6D6 can be used instead of C6 sup>2H6 The symbols for isotopes of elements other than hydrogen and radon are no longer in use within the scientific community. Many of these symbols were designated during the early years of , and several isotopes (namely those in the s of , , and ) bear s using the early naming system devised by .

Other symbols

General: *A: A deprotonated or an *An: any *B: A , often in the context of or *E: any element or *L: any *Ln: any *M: any *Mm: (occasionally used) *Ng: any (Rg is sometimes used, but that is also used for the element : see above) *Nu: any *R: any unspecified radical () not important to the discussion *St: (occasionally used) *X: any (or sometimes ) From organic chemistry: *Ac: – (also used for the element : see above) *Ad: 1- *All: *Am: amyl () – (also used for the element : see above) *Ar: – (also used for the element : see above) *Bn: *Bs: or (outdated) benzenesulfonyl *Bu: (''i''-, ''s''-, or ''t''- prefixes may be used to denote ''iso''-, ''sec''-, or ''tert''- isomers, respectively) *Bz: *Cp: *Cp*: *Cy: *Cyp: *Et: *Me: *Mes: (2,4,6-trimethylphenyl) *Ms: (methylsulfonyl) *Np: – (also used for the element : see above) *Ns: *Pent: *Ph, : *Pr: – (''i''- prefix may be used to denote isopropyl. Also used for the element : see above) *R: In organic chemistry contexts, an unspecified "R" is often understood to be an group *Tf: (trifluoromethanesulfonyl) *Tr, Trt: (triphenylmethyl) *Ts, Tos: (''para''-toluenesulfonyl) – (Ts also used for the element : see above) *Vi: Exotic atoms: *Mu: *Pn: *Ps:

See also

* * *



Elementymology & Elements Multidict
element name etymologies. Retrieved July 15, 2005. *Atomic Weights of the Elements 2001

Retrieved June 30, 2005. Atomic weights of elements with atomic numbers from 1–109 taken from this source.

WebElements Periodic Table
Retrieved June 30, 2005. Atomic weights of elements with atomic numbers 110–116 taken from this source. *Leighton, Robert B. ''Principles of Modern Physics''. New York: McGraw-Hill. 1959. *Scerri, E.R. "The Periodic Table, Its Story and Its Significance". New York, Oxford University Press. 2007.

External links

History of IUPAC Atomic Weight Values (1883 to 1997)
American Chemical Society {{Portal bar, Chemistry, Biology, Physics, Science, Technology, Earth sciences, Education pl:Symbol chemiczny