Structure representation coordination compounds

There remain a small number of structures with stereochemical descriptors that have yet to be converted to atom/bond-specific representation. As noted above, these are a special group of stereoparents and coordination compounds, scheduled for future conversion. r... 

The problems which arise with the electronic representation of chemical structures, especially of organic compounds, have been extensively discussed in Structure Representation. With inorganic compounds these difficulties remain and are further amplified. Whereas in organic compounds an atom is generally connected to at most four neighbouring atoms, in inorganic compounds much larger coordination numbers may... 

Fig. 17. Pictorial representation of the Cl, CI5 and C16 structure type which are assumed by congruent-melting compounds. The coordination number of A and B are n and n respectively.

Fig. 22. (On left) Pictorial representation of the D2d -type structure assumed by congruent-melting AB5 compounds. Where n and n are the coordination numbers surrounding A and B respectively in the structure.

To illustrate the potential diversity of structure and bonding of phosphorus, the classic Lewis representations for each possible coordination number one to six are shown in Fig. 15.4.1. Many of these bonding types have been observed in stable compounds, which are discussed in the following sections. 

Crystals of 5 so far have always been twinned, so accurate bond lengths could not be determined, but the X-ray analysis showed definitely that the compound is monomeric. The structure was confirmed by an electron-diffraction study, carried out at the University of Oslo. A representation is shown in Fig. 2 the molecule is planar, with bond distance Si-N 175.3, N-C 140.0, C=C 134.2 pm. The Si NMR spectrum shows that the silicon atom is deshielded (5 = 78.3 ppm) consistent with low coordination at Si. 

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