Structures and solid-state Gallium-69 NMR spectra of LiGaSi2O6.

Abstract

Crystal structures have been refined from single-crystal X-ray diffraction data for three synthetic LiGaSi2O6 clinopyroxenes, crystallized at 1770 K/6GPa, annealed at 1073 K/1 atm and annealed at 1123 K/1 atm. The structures are similar to that of spodumene(LiAlSi2O6). The space group is C2/c, Z=4. The mean Ga-O1 distance increases and the Ga-O1-Ga angle decreases with an increase of the annealing treatment, suggesting that there are two different electronic states for the octahedral Ga ions. Comparison of the solid-state Ga-69 NMR spectra of quenched and annealed LiGaSi2O6 clinopyroxenes indicates the existence of the two different electronic states for the octahedral Ga ions.