An N.Q.R. study of some inorganic compounds

Abstract

Nuclear quadrupole resonance (n.q.r.) spectroscopy is a solid state technique which, when applied to samples containing quadrupolar nuclei, can elucidate fine structural differences and internal electronic distribution. It has-been applied to a variety of inorganic compounds containing the quadrupolar nuclei, chlorine and cobalt, (i.e. (^35) CL and (^59Co). In order to remove spurious responses on a Robinson type n.q.r. spectrometer, apparatus has been constructed to generate sinusoidal magnetic modulation. Monomeric and chain- structures have been proposed for members of a series of complexes between zinc chloride and ethers. Marked asymmetry in the electric field gradient at chlorine has been reported for tetrachlorides of group IV. Although distortion of the molecules in the solid and disorder in the lattice are likely to produce asymmetry, it is suggested, that pπ-dπ bonding makes a major contribution. Such bonding is postulated for the tetrachlorides above carbon tetrachloride. Zeeman line shape studies on thionyl chloride and tetrachlorophenyl phosphorane have yielded estimates for TT-bonding in the bonds to chlorine. A variable temperature study of the (^59)Co quadrurole resonances of π-cyclopentadienyl cobalt dicarbonyl has revealed the absence of phase changes between 77K and 260K.