Satterlyite, (Fe,Mg) (sub 12) (PO (sub 3) OH)(PO (sub 4) ) (sub 5) (OH,O) (sub 6) ; crystal structure and infrared absorption spectra

The crystal structure of satterlyite (a 11.355, c 5.0394 Aa, V 562.71 Aa (super 3) , space group P31m, Z = 2), from the Big Fish River area, Yukon Territory, Canada, has been solved and refined to R 2.15%. The structure is based on pairs of face-sharing, distorted (Fe,Mg)O (sub 6) octahedra linked by edge-sharing to form double chains along [001]. Each double chain shares ligands with six other double chains, giving a 3D network hosting three unique PO (sub 4) tetrahedra which are corner-linked to the (Fe,MgO (sub 6) ) octahedra. The two unique (Fe,Mg)O (sub 6) octahedra have different occupancies: Fe:Mg ratios of the M1 and M2 sites are 0.838:0.162 and 0.706:0.294, respectively. Two H atoms are to common ligands of the two octahedra; the third, strongly disordered H(3) atom is bonded to the apical O of the P(1)O (sub 4) tetrahedron. Satterlyite is isostructural with holtedahlite, but unlike in the latter there is no carbonate [] phosphate substitution in satterlyite. A structural relationship exists with phosphoellenbergerite.