Boron nitride hexagonal polymorph

Boron nitride (BN) is a versatile ceramic that is found and used in various crystallographic and geometrical forms. Although there are chemical similarities, the conditions for the synthesis and fabrication of each form (hexagonal, cubic, polymorphs of BN, fibers, two-dimensional forms and composites) have different requirements and are... 

Fig. 12.18 Part of the layer structure of the common polymorph of boron nitride, BN. Hexagonal rings in adjacent layers lie over one another so that B and N atoms are eclipsed. This is emphasized by the yellow lines.

Figure 11.11 Units cells of (a) Hexagonal sheet-type (h-BN) (b) Rhombohedral sheet-type (r-BN) (c) Wurtzite-type (w-BN) (d) Zincblende-type (z-BN) polymorphic modifications of boron nitride. The lengths of...

BORON NITRIDE. BN. A highly refractory material with physical and chemical properties similar to carbon. Graphite-like (g-BN), wurzite (w-BN) and zinc blende (z-BN) are known polymorphs of BN corresponding to the graphite (hexagonal) and diamond (cubic) structures. Transformation of g-BN to w-BN occurs at pressures above 12 GPa at relatively low temperature (230°C). 

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