Hydrides of carbon

Williams [1] has given an excellent review on Early Carboranes and Their Structural Legacy and he defines carboranes as follows Carboranes are mixed hydrides of carbon and boron in which atoms of both elements feature in the electron-deficient polyhedral molecular skeleton . According to the electron counting rules [2] for closo- (2n + 2 SE), nido- (2n + 4 SE) and arachno-clusters (2n + 6 SE SE = skeletal electrons, n = number of framework atoms) and the An + 2 n electron Hiickel rule, small compounds with skeletal carbon and boron atoms may have an electron count for carboranes and for aromatics (see Chapters 1.1.2 and 1.1.3). 

Hydrocarbons. —The hydrides of carbon, or hydrocarbons, are very numerous, and form an important group of substances. In many respects they are analogous to the metals, and they yield derivatives comparable with those of the metals. The preparation of some of them has already been described but in order to give a more complete idea of their structure and functions, a short description of other methods of forming them is annexed. 

In Table IX-1 we list values of re and D for a number of important diatomic molecules. A few of these, as the hydrides of carbon, nitrogen,... 

Hydrocarbon. A binary compound of carbon and hydrogen a general term which includes the paraffin, olefin, aromatic, and all other series of hydrides of carbon. 

The simple hydrides of carbon include CH, CH2, (CH)2 and (CH2)2. Of these, CH(s3p3) has a non-classical barrel-shaped structure, as shown in figure 7, with hydrogen cylindrically delocalized around C. The bonding electrons, a non-bonding pair and one unpaired electron are distributed in an annulus... 

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