Divalent

Updated on Dec 20, 2023

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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 H₂S or ionic bonds as in Na₂S.

Divalent anions have a charge of −2, for example S²⁻ and SO₄²⁻.

Divalent cations have a charge of +2, for example Fe²⁺, Ca²⁺ and Hg₂²⁺.

Divalent functional groups include the imino (=NH) and carbonyl (=O).

Water Hardness

The divalent cations Ca²⁺ and Mg²⁺ contribute to the properties of water that cause it to be hard, such as the formation of limescale.

References

Divalent Wikipedia

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