TY - JOUR
T1 - The crystal structure of perloffite
AU - Elliott, P.
AU - Willis, A. C.
PY - 2011
Y1 - 2011
N2 - The structure of perloffite, ideally BaMn2+ 2Fe 3+ 2(PO4)3(OH)3, has been solved and refined from single-crystal X-ray data collected on a Sr-bearing sample from the Spring Creek copper mine, near Wilmington, South Australia. A fragment of the crystal used for the collection of the X-ray intensity data was analysed by electron microprobe. The resulting unit formula is (Ba 1.00,Sr0.03)Σ1.03(Mn2+ 1.15,Fe2+ 0.76Ca0.05Mg 0.02,Na0.01)Σ1.99(Fe3+ 1.94,Al0.06)Σ2.00(PO4) 2.99(OH)3.04. The structure is monoclinic, space group P21/m, a = 9.2425(18), b = 12.470(3), c = 5.002(1) Å, β = 100.19(3)°, V = 567.41(19) Å3, Z = 2, and was refined to R 1 = 4.71% for 1568 unique observed reflections. The X site is [11]-coordinated and is occupied by dominant Ba and minor Sr, with an <X-O> distance of 2.953 Å. The M1 site is octahedrally coordinated and is occupied by Mn2+ and Fe2+ plus minor Ca, Mg and Na with an observed <M1-O> distance of 2.208 Å. The M2 site is also octahedrally coordinated and is occupied by Fe3+ plus minor Al with a <M2-O> distance of 2.018 Å. Perloffite is isostructural with other members of the bjarebyite group. Edge-linked [M22O 6(OH)4] dimers link via corners to form chains along [010]. Chains are decorated with PO4 tetrahedra and link in the a direction via [M1O5(OH)] octahedra and (Ba,Sr) atoms to form a complex framework. The H2 atom hydrogen-bonds strongly to the O3 anion, providing additional linkage between chains.
AB - The structure of perloffite, ideally BaMn2+ 2Fe 3+ 2(PO4)3(OH)3, has been solved and refined from single-crystal X-ray data collected on a Sr-bearing sample from the Spring Creek copper mine, near Wilmington, South Australia. A fragment of the crystal used for the collection of the X-ray intensity data was analysed by electron microprobe. The resulting unit formula is (Ba 1.00,Sr0.03)Σ1.03(Mn2+ 1.15,Fe2+ 0.76Ca0.05Mg 0.02,Na0.01)Σ1.99(Fe3+ 1.94,Al0.06)Σ2.00(PO4) 2.99(OH)3.04. The structure is monoclinic, space group P21/m, a = 9.2425(18), b = 12.470(3), c = 5.002(1) Å, β = 100.19(3)°, V = 567.41(19) Å3, Z = 2, and was refined to R 1 = 4.71% for 1568 unique observed reflections. The X site is [11]-coordinated and is occupied by dominant Ba and minor Sr, with an <X-O> distance of 2.953 Å. The M1 site is octahedrally coordinated and is occupied by Mn2+ and Fe2+ plus minor Ca, Mg and Na with an observed <M1-O> distance of 2.208 Å. The M2 site is also octahedrally coordinated and is occupied by Fe3+ plus minor Al with a <M2-O> distance of 2.018 Å. Perloffite is isostructural with other members of the bjarebyite group. Edge-linked [M22O 6(OH)4] dimers link via corners to form chains along [010]. Chains are decorated with PO4 tetrahedra and link in the a direction via [M1O5(OH)] octahedra and (Ba,Sr) atoms to form a complex framework. The H2 atom hydrogen-bonds strongly to the O3 anion, providing additional linkage between chains.
KW - X-ray diffraction
KW - bjarebyite group
KW - crystal structure
KW - perloffite
UR - http://www.scopus.com/inward/record.url?scp=79960000102&partnerID=8YFLogxK
U2 - 10.1180/minmag.2011.075.2.317
DO - 10.1180/minmag.2011.075.2.317
M3 - Article
SN - 0026-461X
VL - 75
SP - 317
EP - 325
JO - Mineralogical Magazine
JF - Mineralogical Magazine
IS - 2
ER -