Adamantine compound

ADAMANTINE COMPOUND. A compound having in its crystal structure an arrangement of atoms essentially that of diamond, in which... 

Zinc forms a bipositive ion with an 18 electron structure and a moderately small radius (0.74 A). The large ion (1.84 A) is considerably polarised by it and the two forms of ZnS are predominantly homopolar, since both atoms can adopt sp hybridisation and pool their valence electrons. Blende is cubic (Fig. 89), wurtzite hexagonal (Fig. 90), there being an average of 4 electrons per atom for bond formation as in diamond. Homopolar compounds of this type are formed by many pairs of elements whose valency electrons total 8. They are called adamantine compounds and have either a blende or wurtzite structure (see Table 22). 

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