Coordination of boron in nominally boron-free rock forming silicates: Evidence for incorporation of BO3 groups in clinopyroxene
To explore mechanisms of B-incorporation in common chain silicates we have investigated synthetic diopside samples produced under boron-saturated conditions by B-11 and Si-29 magic-angle spinning (MAS) NMR and single-crystal NRA, FTIR, EMP and XRD/SREF techniques. Our samples contain 0.14-0.65 wt.% B2O3. NMR reveals that B is predominantly present in trigonal coordination in the clinopyroxene stru