Crystal structure of correianevesite from the Emmons pegmatite, Uncle Tom Mountain, Greenwood, Oxford County, Maine

Abstract

Correianevesite, Fe2+Mn2+2(PO4)2·3H2O, is an uncommon secondary phosphate in granitic pegmatites. Described for the first time from the Cigana pegmatite (Conselheiro Pena, Brazil), it was subsequently reported only at the Berry-Havey pegmatite (Androscoggin County, Maine, U.S.A.). A single crystal from a new occurrence at the Emmons pegmatite, Oxford Co., Maine, gave the following unit cell unit cell parameters: a = 9.4872(19), b = 10.121(2), c = 8.7023(17) (Å), V 835.6(3) (Å3). The structure was anisotropically refined in the orthorhombic system, space group Pbna down to a R = 1.6% and the hydrogen-bond pattern could be determined. Microprobe chemical analysis, and bond valence calculation show the expected values for all the atomic sites and confirmed the valence of all ions in the structure.