Magnitudes and orientations of NMR interaction tensors in isolated three-spin systems ABX

Possibilities and limitations for the complete determination of all orienta tional parameters from iterative fitting of various MAS NMR spectra of ABX three-spin systems are explored. The practical example chosen is the (P-31) (2) Cd-113 ABX spin system in solid Cd(NO3)(2). 2PMe(2)Ph, where Cd-113 is an X nucleus of low natural abundance. Conventional P-31 and Cd-113 MAS NMR spectra, plus Cd-113 MAS NMR spectra obtained under conditions of either s imultaneous high power P-31 and H-1 decoupling, or under conditions of P-31 rotary resonance recoupling are considered. Considerable anisotropy of the heteronuclear J coupling (1)J(Cd-113, P-31) is observed.