八個一組,八價元素
Octad \Oc"tad\, n. [Gr. ?, ?, the number eight.] (Chem.) An atom or radical which has a valence of eight, or is octavalent.
octad n : the cardinal number that is the sum of seven and one [syn: {eight}, {8}, {VIII}, {eighter}, {eighter from Decatur}, {ogdoad}, {octonary}, {octet}]