Phenacite-type structure

Ge nitride, GesN4, is formed as a black solid from Ge and ammonia at 650 °C, or by heating the imide [Ge(NH)2] at 400 °C. It exists in two forms, both of which have a phenacite-type structure. It decomposes to the elements at 900 °C. GesNq is stable to air and insoluble in HCl, HNO3, H2SO4, and NaOH aqueous. At 700 °C, reaction of Ge3N4 with H2 results in Ge and NH3. 

Colorless powder when pure however, Crystallizes in a phenacite-type structure. 

TABLE 9. C omparisonof AverageHeatsof Atomization(Hs, in kcal/g-atom), Average Heats of Formation (Estimated from Electronegativity Differences, Ax 1% = 23(Ax), in kcal/g-atom) of Defect Tetrahedral Structures (Related to Wurtzite or Zinc Blende Type) and Phenacite-Type... 

Under pressure, LiZnV04 transforms from less dense phenacite to more dense spinel type structure [29],... 

Betyllium, because of its small size, almost invariably has a coordination number of 4. This is important in analytical chemistry since it ensures that edta, which coordinates strongly to Mg, Ca (and Al), does not chelate Be appreciably. BeO has the wurtzite (ZnS, p. 1209) structure whilst the other Be chalcogenides adopt the zinc blende modification. BeF2 has the cristobalite (SiOi, p. 342) structure and has only a vety low electrical conductivity when fused. Be2C and Be2B have extended lattices of the antifluorite type with 4-coordinate Be and 8-coordinate C or B. Be2Si04 has the phenacite structure (p. 347) in which both Be and Si... 

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