Cyanides, Cyanates, and Related Species

Derivatives of Group V Elements.—Cyanogen, Cyanides, Cyanates, and Related Species. The number of papers published during the period of this Report which describe the chemistry of these species is markedly lower than that for previous Reports. Theoretical calculations of the electronic structures of HCN,225 HNCS,226 and the CN radical227 228 have been successfully completed. The electronic structure of HNCS has been compared with that of HNCO226 and it is concluded that (i) the 77-system in HNCS involves a nitrogen lone pair stabilized by a C—S 77-bond, whereas the 77-system in HNCO consists of a C—O 77-bond stabilized by the nitrogen lone pair, and (ii) the d -orbitals of sulphur accept electron density in a 7- rather than a 77-fashion. The electronic structure of the NCS ion has also been determined experimentally from the X-ray Kp fluorescence and K absorption spectra of the S atom in KSCN.229 

Carsky, M. Machacek, and R. Zahradnik, Coll. Czech. Chem. Comm., 1973, 38, 3067. 

Ab initio calculations of the molecular geometry and vibrational properties of the hydrogen-bonded complex between HCN and HF have been effected.230 The complex (24) is predicted to be linear, HF being the proton 

Orbital assignment lir-(C—P bonding) 3o--(P lone pair) 2 r-(C—H bonding) 

The oxidation of (CN)2 in (CN)2-02-Ar mixtures and the distribution of the reaction products before and after ignition have been studied behind 

Derivatives of Group V Elements.—Cyanogen, Cyanides, Cyanates, and Related Species. As for previous Reports, the data abstracted for this section fall into categories associated with the molecular and chemical properties of these species. Particular interest has been shown in the structure of HCP, and in the reactions of CN in MeCN. Several detailed analyses of the spectroscopic properties of these molecules have been undertaken they are summarized in Table 14. Ab initio 

calculations have been carried out to facilitate the analysis of the vibrational 

The equilibrium geometry of HCP has been derived in two independent ab initio theoretical analyses the results of both calculations are in reasonable agreement with the experimental data (Table 15). The nature of the C—bond 

spectra of matrix-isolated MCN (M = Na or K) have been examined they were interpreted assuming monomers, dimers, and higher polymers to be present. The dimers are thought to have the form of a rhombic tetra-atomic ring, composed of metal and carbon atoms (34). q— 

Miyazaki, M. Ikeda, and M. Shibata, Bull. Chem. Soc. Japan, 1975, 48, 1138. 

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Table 14 Recent spectroscopic studies of cyanides, cyanates, and related species...

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