Site occupancy refinement of osumilite

Publisher Website
Google Scholar
Abstract
The structure of osumilite from Nain, Labrador, (Na 0.14 K 0.86 ) [12] (Mg 1.44 Fe 0.56 ) [6] (Mg 0.23 Fe 0.16 Al 2.61 ) [4] (Si 10.36 Al 1.64 ) [4] O 30 is hexagonal with space group P 6/ mcc , a 0 = 10.126(2), c 0 = 14.319(3) Å, Z = 2 and D x = 2.63 g/cm 3 , and was refined to R (unweighted) = 0.033 and R (weighted) = 0.026 using 590 nonequivalent reflections. The basic structure determined by Brown and Gibbs (1969) was confirmed. It was shown, however, that part of both Fe 2+ and Mg 2+ enter the T2 position (T2 – O distance 1.772 Å) and are not strongly fractionated between this and the octahedral M position (M – O distance 2.135 Å). No other site contains Mg 2+ or Fe 2+ in this osumilite.