Site discrimination in the crystalline borophosphate Na5B2P3O13 using advanced solid-state NMR techniques

A comprehensive solid-state NMR investigation on crystalline Na5B2P3O13 is presented. Triple-quantum magic angle spinning (TQMAS) and rotational echo double resonance (REDOR) studies are used for accurate determinations of the 11B, 23Na and 31P interaction parameters. Based on these results and complementary quantum mechnical calculations, plausible site assignments can be derived. Generally, the results show that detailed, quantitative information about structures in borophosphate compunds can be obtained by investigating both the local site environments characterized by chemical shift and quadrupolar interaction parameters and the correlated dipolar interactions to atoms in the second coordination sphere.