... & Kostov-Kytin 2013 ), both possess the same principal structural unit: a 2 [ M ( T O 4 ) 2 ] layer, consisting of corner-sharing M O 6 octahedra and T O 4 tetrahedra ( Nikolova & Kostov-Kytin 2013 ) and having fully occupied M and T sites. However, the arrangements of the T O 4 tetrahedra...

... parameters a = 7.7651(14), c = 9.6199(17) Å, V = 502.3(2) Å 3 , and Z = 1. Its crystal structure consists of two unique Pb polyhedra [Pb1 coordinated by (5O + 3OH) and Pb2 by (5O + 2OH + F + Cl)], one M 3+ (OH) 6 octahedron ( M = Cr 3+ + Fe 3+ ), two Cr 6+ O 4 tetrahedra (Cr1 and Cr2), and one SO 4...

...), 2.384 (35) ( $\bar{2}$ 01), 3.130 (30) ( $\bar{1}$ 21), 2.811 (30) (030) and 2.316 (18) (032). The crystal structure (solved and refined from single-crystal X-ray diffraction data, R 1 = 0.07) is a new layered structure consisting of corner-sharing tetrahedrons and octahedrons, where [PO 4 ] tetrahedra...

... consisting of two upward-pointing (u) and two downward-pointing (d) tetrahedra, and (2) an eight-membered ring consisting of alternately upward-pointing (u) and downward-pointing tetrahedra (d). The u-d arrangement in the fluorcarletonite and carletonite tetrahedra sheet is (u 2 d 2 ) 4 (udududud) 4 (see...

... and Z = 4. In the structure of shinarumpite ( R 1 = 0.0336 for 2623 I > 2σ I ), linkages of pentagonal bipyramids and tetrahedra form an infinite [(UO 2 )(SO 4 ) 2 (H 2 O)] 2– sheet. Isolated Co(H 2 O) 6 octahedra and H 2 O groups occupy the interlayer region linking the sheets via an extensive...

...(11) Å, β = 91.272(5)°, V = 342.47(14) Å 3 and Z = 2. Its crystal structure is characterised by a framework of corner-sharing PO 4 and BeO 4 tetrahedra. The framework can be considered as built from the stacking of sheets consisting of 4- and 8-membered rings (4.8 2 nets) along [001] or hexagonal...

..., is based on a loose 3D framework of alternating AsO 3 OH tetrahedra and Fe 3+ O 6 octahedra. * Author for correspondence: Anthony R. Kampf, Email: akampf@nhm.org Associate Editor: Juraj Majzlan 16 03 2022 29 05 2022 Copyright © The Author(s), 2022. Published by Cambridge...

...Javier Cuadros; Joseph R. Michalski; M. Darby Dyar Abstract The model of Fe 3+ distribution between octahedra and tetrahedra in dioctahedral smectites by Decarreau and Petit (2014) used data from infrared analysis. From their own and other general evidence, the resulting data are likely...

... 4 3 + = Fe 3+ /(Fe 3+ +Al 3+ ) molar ratio in tetrahedra, 4 and 6 referring to tetrahedral and octahedral sites (similar relations for Al 3+ ), and a Kd (4/6) value of 0.006 was obtained from the fit of data from natural smectites formed at low temperature. This very low Kd (4/6) value...

... 1 , 212). The crystal structure, solved using single-crystal X-ray diffraction data, R 1 = 0.025, is based upon complex [O 4 Cu 9 ] 10+ layers parallel to ( 1 01) that are composed of edge- and corner-sharing (OCu 4 ) tetrahedra. The topology is unprecedented in inorganic structural chemistry...

...Maxwell C. Day; Frank C. Hawthorne Abstract A structure hierarchy is developed for chain-, ribbon- and tube-silicate based on the connectedness of one-dimensional polymerisations of (TO 4 ) n − tetrahedra, where T = Si 4+ plus P 5+ , V 5+ , As 5+ , Al 3+ , Fe 3+ , B 3+ , Be 2+ , Zn 2+ and Mg 2...

.... Each uranyl phosphate studied has a topologically identical anionic sheet of uranyl square bipyramids and phosphate tetrahedra combined with various cations (Li + , Na + , K + , Rb + , Cs + , Mg 2+ , Ca 2+ , Ba 2+ ) and water in the interlayer. Uranyl peroxides formed under many of the experimental...

... Å, respectively, from Shannon 1976 ) and divalent electric charge that does not balance efficiently the negative charge of oxide anions in corner-shared tetrahedra. Iron(III), however, with a trivalent charge and smaller radius (tetrahedral ionic radius of 0.57 Å; Whittaker and Muntus 1970 ) mitigates totally...

...+ and Fe 3+ ions in neighboring T(3) tetrahedra. When both configurations are present, the crystal assumes a shade of green, depending on their relative proportion. The electrons released by the irradiation are trapped at sites which are probably associated with water molecules in the beryl channels...

... plane leads to a highly disrupted coordination, where only half of the tetrahedra are restored. This makes a contact twin highly unlikely. The reported twin is actually a penetration twin, in which the irregular composition surface may have compensated, to some extent, the unfavourable structural match...

..., which demonstrate the remarkable diversity of Cu 2+ mixed-ligand coordination environments. The crystal structure of dokuchaevite is based on OCu 4 tetrahedra that share common corners thus forming [O 2 Cu 6 ] 8+ single chains. Two of the eight symmetrically independent copper atoms do not form Cu–O...

... of both minerals comprise heteropolyhedral slabs of composition [ XM 1 Fe 2 3 + (OH) 2 (PO 4 ) 4 ], that are linked together via corner-sharing of PO 4 tetrahedra with isolated [ M 2(O p ) 2 (H 2 O) 4 ] octahedra. The structures differ in the mode of linkage of the M 2 octahedra, which is via trans O p...