Orthominasragrite, V4+O (SO4) (H2O)5, a new mineral species from Temple Mountain, Emery County, Utah, USA

Orthominasragrite, V4+O (SO4) (H2O)(5). is a new mineral species from Temple Mountain, Emery County, Utah. It occurs as rounded aggregates (up to similar to 200 mum across) of irregular grains that are pale blue to bright blue, depending on size. Orthominasragrite has a pale blue streak, a vitreous luster, and no observable fluorescence under ultraviolet light, It has no cleavage or parting. The Mobs hardness is similar to 1, and the calculated density is 2.00 g/cm(3). Orthominasragrite is biaxial negative (pseudo-uniaxial) with alpha 1.529(2), beta 1.534(2), gamma 1.534(2), 2V(obs) = 2(4)degrees, 2V(calc) = 0 degrees, non-pleochroic, X = b, Y = c, Z = a, Orthominasragrite is orthorhombic. space group Pmn2(1), a 7.246(4), b 9.333(6), c 6.210(4) Angstrom, V420.0(3) Angstrom (3), Z= 2. The strongest seven lines in the X-ray powder-diffraction pattern [d in Angstrom (I)(hkl)] are as follows: 4.699(10)(101,020), 3.322(5)(121), 2.865(4)(220), 2.602(3)(221,131,022), 3.734(2)(021), 3.622(2)(200), and 3.108(2)(002). Chemical analysis by electron microprobe gave VO2 33.88, SO3 31.97, H2O (calc.) 36.30, sum 102.15 wt.%; the proportion of H2O was determined by crystal structure analysis. The resulting empirical formula on the basis of 10 anions (including 5 H2O) is V-1.014 S-0.991 O-5 (H2O)(5) the endmember formula is VO (SO4) (H2O)(5). Orthominasragrite is the orthorhombic form of (monoclinic) minasragrite. The crystal structure was solved by direct methods and refined to an R index of 4.4% for 1007 observed (\F-o\ > 5 sigmaF) reflections measured with an automated four-circle X-ray diffractometer using MoK alpha X-radiation. There is one V site occupied by V4+ and surrounded by one O atom and 5 (H2O) groups in an octahedral arrangement, with one short apical vanadyl bond (1.580 Angstrom), four similar equatorial bonds (<2.026 Angstrom >), and one longer V-O bond (2.231 Angstrom) trans to the vanadyl bond. The structure consists of isolated (V-phi6(4+)) octahedra (phi): unspecified anion) and (SO4) tetrahedra linked by hydrogen bonds.