The first observation of heteronuclear two-bond J-coupling in the solid state:: Crystal structure and solid-state NMR spectroscopy of Rb4(NbO)2(Si8O21)

High-temperature, high-pressure hydrothermal synthesis of the title compound and its Nb-93 and Si-29 MAS NMR spectra are reported. The Si-29 MAS NMR spectrum shows four signals corresponding to the four distinct Si sites in the structure. Three signals show multiplet patterns which arise from Nb-93(spin-(9)/(2))-Si-29 J-coupling. This is the first example of two-bond J-coupling between a quadrupolar nucleus and a spin-(1)/(2) nucleus in the solid state. A combination of Nb-93 and Si-29 solid-state NMR and X-ray diffraction data has provided a correlation between NMR interaction parameters and local structure. This work opens a new opportunity to examine the relationship between (2)J-coupling and structural parameters in the solid state.