Boron compounds Terms Links

CaB6 can be described in terms of the Wade rules. In this compound the B6 octahedra are linked with each other via 2e, 2c bonds six electrons per octahedron are required for these bonds, together with the 2n + 2 (= 14) electrons for the octahedron skeleton. This adds up to a total of 20 valence electrons. The boron atoms give 3 X 6 = 18 of these and calcium the remaining two. 

In boron-rich compounds, the structure can often be described in terms of a three-dimensional network of boron clusters (octahedra, icosahedra, and cubo-octahedra), which are linked to one another directly or via non-cluster atoms. 

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