Crystal structure of fabianite, CaB3O5(OH), and comparison with the structure of its synthetic dimorph
No abstract available.
Zeitschrift für Kristallographie — Crystalline Mat↗
Geology topics
Joan R. Clark
Publications and source records attributed to Joan R. Clark.
Pentaborate polyanion in the crystal structure of ulexite, NaCaB 5 O 6 (OH) 6 *5H 2 O
Triclinic ulexite crystals contain isolated borate polyanions [B 5 O 6 (OH) 6 ] 3- related to the well known pentaborate polyanion [B 5 O 6 (OH) 4 ] - by addition of two hydroxyl groups to two opposite B-O triangles. The isolated ulexite polyanions form the [B 5 O 7 (OH) 4 ] n 3n- chains previously found in crystals of the related mineral probertite, NaCaB 5 O 7 (OH) 4 ·3H 2 O.
Science↗
Some observations on rutherfordine
The optical properties of rutherfordine, UO 2 CO 3 , previously determined on microscopic crystals, have been redetermined on considerably larger crystals; and the relations among the indices of refraction, the morphology, and the crystal structure have been examined. Rutherfordine is orthorhombic, biaxial positive, with α = 1.715, β = 1.730, γ = 1.795, 2V = 53° (calc.); X = b, Y = c (elongation, Z = a. The crystal structure of UO 2 CO 3 consists of layers of carbonate groups parallel to (010) with linear (O-U-O) ions normal to the layers. The indices β and γ correspond to vibration directions parallel to layers; the unexpectedly large difference in value between β and γ is ascribed to the optical anisotropy of the uranium-oxygen bonding in the layer. Indexed X-ray powder data are given.
Trace Elements Investigations↗
The crystal structure of potassium metavanadate monohydrate, KVO3*H2O
No abstract available.
Trace Elements Investigations↗