The ³¹P NMR Chemical Shielding Tensors in Quaternary Metal Thiophosphates, NaNb₂PS₁₀, AgNb₂PS₁₀, Au_0.5Nb₂PS₁₀, and NaSmP₂S₆

For quaternary metal thiophosphates, NaNb 2 PS 10, AgNb 2 PS 10, Au 0.5 Nb 2 PS 10, and NaSmP 2 S 6, the principal elements of the 31 P NMR chemical shielding tensor (δ 11, δ 22, and δ 33 ) are acquired from the nonlinear least-squares fitting the static powder patterns and MAS spectra. Isotropic chemical shift (δ iso ) and chemical shielding anisotropy (Δδ) have been employed to correlate with the X-ray crystallographic data, the average (P−S) bond length and the average (S−P−S) bond angle deviation from 109.5°, respectively, at the tetrahedrally coordinated phosphorus atoms. On the basis of these successful correlations, the charge transfer from Na, Ag, and Au metals to the (P−S) ligand is discussed and complemented by the band-structure calculation.