Divalent
From Infogalactic: the planetary knowledge core
In chemistry, a divalent (sometimes bivalent[1]) 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
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The divalent cations Ca2+ and Mg2+ contribute to the properties of water that cause it to be hard, such as the formation of limescale.[2]
See also
References
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- ↑ World Health Organization Hardness in Drinking-Water, 2003
