Beryllium wurtzite structure

The use of radius ratios to rationalize structures and to predict coordination numbers may be illustrated as follows.27 Consider beryllium sulfide, in which rn,a /r5i- = 59 pm/170 pm = 0.35. We should thus expect a coordination number of 4 as the Be2+ ion fits most readily into the tetrahedral holes of the closest packed lattice, and indeed this is found experimentally BcS adopts a wurtzite structure. 

Beryllium oxide is covalent and has a zinc blende (wurtzite) structure, but all the others are ionic and have a rock salt structure (Figure 3). Attempts to predict the structures (using the ionic sizes and the radius ratio) only are partly successfijl. 

Binary compounds are formed with all nonmetallic elements, many by direct combination. Beryllium is exceptional as its coordination is almost always tetrahedral, giving structures that may be regarded as polymeric rather than highly ionic. Thus BeO has the wurtzite structure (see Topic D3). BeF2 is... 

Beryllium Oxide and Oxides with the Wurtzite Structure... 

In beryllium oxide, which has the wurtzite structure, the diffusion of beryllium has been studied ( ). Here again it appears that the ratio of diffusion. 

Fig. 4. Computer-generated crystal structure models nop row. left to right) Cuprite, zinc-blende, rutile, perovskite. iridymite (second row) Cristobalite. potassium dihydrogen phosphate, diamond, pyrites, arsenic (third rowt Cesium chloride, sodium chloride, wurtzite. copper, niccolite (fourth row) Spinel, graphite, beryllium, carbon dioxide, alpha i uanz. [AT T Bel Laboratories ...

Beryllium, 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. Bep2 has the cristobalite (SiOz, p. 342) structure and has only a very low electrical conductivity when fused. Bc2C and Bc2B 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... 

Beryllium oxide, BeO, is formed by ignition of Be or its compounds in O2. It is an insoluble white sohd which adopts a wurtzite-type structure (see Figure 6.20). The... 

Fig. lr.1-132 The Brillouin zone of the wurtzite lattice Table ir.1-101 Band structures of beryllium compounds... 

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