Steven Dec - 27Al Solid-State Nuclear Magnetic Resonance Study of Five-Coordinate Aluminum in Augelite and Senegalite

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      Publication Details (including relevant citation   information):

    1. 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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