Solid-state 31 P magnetic resonance shifts and fine structure

Abstract

The 31 P chemical shifts and spectral structure have been determined in a number of solid phosphorus compounds by means of the rapidly rotating specimen technique. The theory is first given of the narrowing of dipolar-broadened nuclear magnetic resonance spectra by rapid rotation of solid specimens about an axis inclined at an angle 54° 44' to the applied field. The effect of rotation on other nuclear interactions is discussed, and in particular it is shown that the chemical shift tensor is effectively replaced by its isotropic mean value. The method has been applied to the measurement of 31 P chemical shifts in polycrystalline phosphorus compounds: phosphorus sesquisulphide, tetraphosphorus pentasulphide, phosphorus pentasulphide, pyrophosphoric acid, phosphorus pentachloride and zinc phosphide. Four compounds showed two or more chemically shifted lines. The shifts determined are discussed and are compared with those for related compounds studied in the liquid state.