What is "divalent"

Divalent \Div"a*lent\, a. [Pref. di- + L. valens, valentis, p. pr. See Valence.] (Chem.) Having two units of combining power; bivalent. Cf. Valence.

a. (context chemistry English) Having a valence of two.

adj. having a valence of two or having two valences [syn: bivalent]

In chemistry, a divalent (sometimes bivalent) element, ion, functional group or molecule has a valence of two. Valency is the number of chemical bonds formed, which may be covalent, polar covalent or ionic.

Examples:

• Divalent elements include calcium and sulfur. While the bonds formed by calcium are ionic, sulfur can form covalent bonds as in HS or ionic bonds as in NaS.
• Divalent anions have a charge of −2, for example S and SO.
• Divalent cations have a charge of +2, for example Fe, Ca and Hg.
• Divalent functional groups include the imino (=NH) and carbonyl (=O).