Publication Details (including relevant citation information):
- W.F. Bleam; S.F. Dec and J.S. Frye., Physics and Chemistry of Minerals, 16, 817 (1989).
This is a report of 27Al magic-angle spinning, nuclear magnetic resonance spectroscopy of 5- and 6-coordinate aluminum in the aluminophosphate minerals augelite and senegalite. We have determined the quadrupolar coupling constants, asymmetry parameters and chemical shifts corrected for quadrupolar-induced shift for both aluminum coordination sites in each mineral. The quadrupolar coupling constants are significantly less in senegalite than in augelite. Structural analysis (viz., longitudinal- and shear-strain of the aluminum coordination polyhedra; coefficient-of-variation for both Al-O bond lengths and <O-Al-O bond angles) shows that both 5- and 6-coordinate aluminum sites in senegalite are less distorted than in augelite.
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