A chemical symbol is a one-to-three-letter abbreviation used to represent an element. For example, the element hydrogen's chemical symbol is H, while the element chlorine's symbol is Cl. Some elements symbols are derived from their Latin names, so their letters are not necessarily from the elements' modern name. For example, lead's symbol is Pb, which is from the Latin word for lead, plumbum. Newly-developed synthetic elements are given temporary names corresponding to their atomic numbers. Element 106 is called Unnilhexium.