Calcium hexaboride

Calcium hexaboride. An introductory example is represented by the calcium boride (CaB6) in which, however, boron octahedra are not condensed with each other but connected via normal (2e, 2c) bonds. A scheme of the structure is shown in Fig. 4.29. It is cubic, space group, Pm3m, N.221 with ... 

Fig. 10-2.—The atomic arrangement in the cubic crystal calcium hexaboride, CaB ...

The fact that the expected product BH3 is not obtained will be discussed in a later section. Some metals form borides containing the hexaboride group, B62. An example of this type of compound is calcium hexaboride, CaB6. In general, the structures of compounds of this type contain octahedral B62 ions in a cubic lattice with metal ions. Most hexaborides are refractory materials having melting points over 2000 °C. 

A third synthesis route which is used today begins from calcium hexaboride, according to ... 

Jash, R and Trenary, M. Synthesis of crystaUine boron nanoribbons and calcium hexaboride nanowires by low pressure chemical vapor deposition. Journal of Physics Cortference Series, 21MI9,176,012011(1-11). 

Ca4Ti3O10 4-CALCIUM 3-TITANIUM 1(K)XIDE 472 CeB6 CERIUM HEXABORIDE 509... 

A note about the bonding and electron requirements is that the Be octahedron has been calculated to be two-electron deficient when bonding in solids, namely, it lacks two electrons to satisfy the bonding orbitals. Therefore, for trivalent rare earth atoms, which supply three electrons, there is one extra electron in the conduction band, and RBg for trivalent rare earths can be well understood to be good metals. When the metal atom is divalent, such as for europium in the divalent state and calcium, the hexaboride becomes semiconducting or similar to a semimetal. 

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