Chemical symbol

arbitrary or conventional sign used in chemistry to represent an element (or sometimes a functional group or a class of elements)

A chemical symbol is the shortform of the name of an element. Usually, it is made up of one or two letters, but sometimes it is made up of three letters. For example, the chemical symbol for oxygen is O. The chemical symbol for calcium is Ca. Before it is discovered and scientists decided what it would be called, the chemical symbol for ununennium was Uue.

All chemical symbols start with a capital letter, and any letters after that are lowercase.

The chemical symbols are listed with the elements in the periodic table. Chemical symbols are also used when writing chemical formulas. For example, the chemical formula for water is H2O, meaning that it contains two hydrogen atoms and one oxygen atom.

Many chemical symbols are the first one or two letters of the element. Others come from the name in another language. For example, the symbol for sodium is Na, which comes from the Latin name Natrium.


  • "Chemical Symbols and Formulas". Chemistry LibreTexts. March 17, 2022.