Boron Nitride, Metal Borides, etc

Boron Nitride, Metal Borides, etc.—U.v. and e.s.r. spectra of B2 trapped in an argon matrix at 10 K are consistent with the ground state being This compares with the ground state which is favoured by ab initio calculations.  

The anisotropy of the X-ray emission bands for BN crystals can be used to separate these into o-- and -components. The width of the ir-band was found to be 7.0 eV, while that of the cr-band was 11.7 eV. As there is an overlap between the bands of 6.8 eV, this corresponds to a total width for the valence band of 12.9 eV. All of these results were rather similar to those for graphite.  

The boron-rich boron arsenide Bi2(Asi.77Bo 23) is rhombohedral, belonging to the space group R3m. The structure is related to those of B12P2 and a-rhombohedral boron.  

X-Ray data on a boron-rich titanium boride (E. Amberger and K. Polbom, Acta Cryst., 1975, B31,942) have been re-interpreted by Ploog as suggesting that the 2(b) positions are occupied by C and not by B atoms this is said to lead to a stabilization of the tetrahedral arrangement of the B12 icosahedra. A further paper by the original authors, however, denies that C atoms can be present in this structure.  

Beyreuther, R. Hierl, and G. Wiech, Ber. Bunsengesellschaft. phys. Chem., 1975, 79, 108. 

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