Crystal-chemical classification of borates

Bokii, G. B.; Kravchenko, V. B.

doi:10.1007/bf00761178

Cited by 8 publications

(6 citation statements)

References 88 publications

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“…Larger-cation polyhedra have lower mean bond valences and can link to sulfate groups without violating the valence-sum rule, and such linkages constitute the structures of the sulfate minerals. Bokii and Gorogotskaya (1969), Sabelli and Trosti-Ferroni (1985), Pushcharovskii (1989), Pushcharovsky et al (1998) and have presented classification schemes with various degrees of comprehensiveness. The most recent scheme subdivides the sulfate minerals into the following groups: (1) sulfates with divalent-and trivalentmetal octahedra;…”

Section: Sulfate Mineralsmentioning

confidence: 99%

The structure hierarchy hypothesis

Hawthorne

2014

Mineral. mag.

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The structure hierarchy hypothesis states that structures may be ordered hierarchically according to the polymerization of coordination polyhedra of higher bond valence. A mathematical hierarchy is an ordered set of elements where the ordering reflects a natural hierarchical relation between (or arrangement of) the elements. Here, I review the structure hierarchies for the borate, uranyl oxide, phosphate, sulfate, beryllate and oxide-centred Cu, Pb and Hg minerals (plus synthetics where appropriate). Structure hierarchies have two functions: (1) they serve to organize our knowledge of minerals (crystal structures) in a coherent manner; (2) if the basis of the classification involves factors that are related to the mechanistic details of the stability and behaviour of minerals, then the physical, chemical and paragenetic characteristics of minerals should arise as natural consequences of their crystal structures and the interaction of those structures with the environment in which they occur. We may justify the structure hierarchy hypothesis by considering a hypothetical structure-building process whereby higher bond-valence polyhedra polymerize to form the structural unit. The clusters constituting the FBBs (fundamental building blocks) may polymerize to form the following types of structural unit: (1) isolated polyhedra; (2) clusters; (3) chains and ribbons; (4) sheets; and (5) frameworks. The major advantage of this approach to structure hierarchy is the fact that the hypothetical structure-building process outlined above resembles (our ideas of) crystallization from an aqueous solution, whereby complexes in aqueous and hydrothermal solutions condense to form crystal structures, or fragments of linked polyhedra in a magma condense to form a crystal. Although our knowledge of these processes is rather vague from a mechanistic perspective, the foundations of the structure hypothesis give us a framework within which to think about the processes of crystallization and dissolution.

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Section: Sulfate Mineralsmentioning

confidence: 99%

The structure hierarchy hypothesis

Hawthorne

2014

Mineral. mag.

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“…These two building blocks can be combined with themselves or to each other in various ways to form layers, rings, chains, or other sorts of 3D networks. − Recently, Wu et al reported on a borosilicate that shows an association of four BO 4 tetrahedra forming a large B 4 O 10 tetrahedron . Until then, this B–O building block has only been predicted in borate chemistry . However, this structural motif is well-known in sulfides (GeS 2 ) and nitrides (Li 10 P 4 N 10 ) and is called a “supertetrahedron”. , The first supertetrahedron appeared in 1987, but the interest in this structural motif, which mostly effectuates the structure to be very porous, began with the work of Yaghi et al in 1994 .…”

Section: Introductionmentioning

confidence: 99%

The Indium Borate In₁₉B₃₄O₇₄(OH)₁₁ with T2 Supertetrahedra

et al. 2016

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The trigonal indium borate InBO(OH) was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 13 GPa and 1150 °C. The crystal structure could be determined by single-crystal X-ray diffraction data collected at room temperature. InBO(OH) crystallizes in the trigonal space group R3̅ (Z = 3) with the lattice parameters a = 1802.49(6) pm, c = 1340.46(5) pm, and V = 3.7716(3) nm. The structure of InBO(OH) contains alternating B-O T2 supertetrahedra units. The presence of hydroxyl groups was confirmed with vibrational spectroscopic methods such as Raman and IR. Besides HInBO, InBO(OH) is now the second known compound in the system In-B-O-H.

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“…It is formed by condensation of four triborate rings in a certain way: two groups are linked via two shared tetrahedra. This group of four BO 4 tetrahedra forming a large B 4 O 10 tetrahedron was first derived theoretically by Bokii and Kravchenko in 1966 [69]. All boron atoms in this 4B-group are tetrahedrally coordinated because each tetrahedron belongs to two 3B-rings.…”

Section: Introductionmentioning

confidence: 99%

Borates—Crystal Structures of Prospective Nonlinear Optical Materials: High Anisotropy of the Thermal Expansion Caused by Anharmonic Atomic Vibrations

et al. 2017

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Abstract:In the present study the thermal structure evolution is reviewed for known nonlinear optical borates such as β- (98-348 K). In addition to the established criteria for nonlinear optical (NLO) properties of crystals, here the role of the anisotropy and anharmonicity of the thermal vibrations of atoms is analysed as well as changes in their coordination spheres and the anisotropy of the thermal expansion of the crystal structure. Non-centrosymmetric borates, especially those that have NLO properties, often show distinct anisotropies for each cation in comparison to centrosymmetric borates. All considered NLO borates contain BO 3 triangles, which are the principal cause of the strong anisotropy of the thermal expansion.Keywords: NLO borates; crystal structures at low and high temperatures; rigid boron-oxygen groups; anisotropic and anharmonic atomic vibrations; thermal expansion; low-and high-temperature single-crystal and powder X-ray diffraction

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Crystal-chemical classification of borates

Cited by 8 publications

References 88 publications

The structure hierarchy hypothesis

The structure hierarchy hypothesis

The Indium Borate In₁₉B₃₄O₇₄(OH)₁₁ with T2 Supertetrahedra

Borates—Crystal Structures of Prospective Nonlinear Optical Materials: High Anisotropy of the Thermal Expansion Caused by Anharmonic Atomic Vibrations

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Crystal-chemical classification of borates

Cited by 8 publications

References 88 publications

The structure hierarchy hypothesis

The structure hierarchy hypothesis

The Indium Borate In19B34O74(OH)11 with T2 Supertetrahedra

Borates—Crystal Structures of Prospective Nonlinear Optical Materials: High Anisotropy of the Thermal Expansion Caused by Anharmonic Atomic Vibrations

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The Indium Borate In₁₉B₃₄O₇₄(OH)₁₁ with T2 Supertetrahedra