Word Study
Hexad
CIDE DICTIONARY
Hexad, n. [L. hexas, hexadis, the number six, Gr. , , fr. "e`x six.].
An atom whose valence is six, and which can be theoretically combined with, substituted for, or replaced by, six monad atoms or radicals; as, sulphur is a hexad in sulphuric acid. Also used as an adjective. [1913 Webster]
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