Compression Crystal orbital calculations

In this book we are particularly interested in simple descriptions of structures that are easily visualized and providing information of the chemical environment of the ions and atoms involved. For metals, there is an obvious pattern of structures in the periodic table. The number of valence electrons and orbitals are important. These factors determine electron densities and compressibilities, and are essential for theoretical band calculations, etc. The first part of this book covers classical descriptions and notation for crystals, close packing, the PTOT system, and the structures of the elements. The latter and larger part of the book treats the structures of many crystals organized by the patterns of occupancies of close-packed layers in the PTOT system. 

In a recent study of the electronic and vibrational spectra of the /x-amido-decamminedicobalt(III) ion (I), Chester and Brubaker have assigned the spectral bands on the basis of molecular orbital and normal coordinate analysis calculations (34). They concluded that the two halves of the ion (the Co(NH3)5 groups) are electronically independent of each other and assigned the electronic transitions on the basis of a simple tetragonal crystal field with axial compression. The calculations also supported the conclusion that the bonds in the Co-N-Co bridge are very similar to simple C0-NH3 bonds. 

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