Darstellung und Systematisierung von Boraten und Polyboraten

Heller, Gert

doi:10.1007/bfb0050798

Cited by 16 publications

(4 citation statements)

References 124 publications

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“…In borate minerals, B may occur as (Bj 3 ) and (Bj 4 ) groups (j = O 2À , OH), and polymerization of these two types of polyhedron is extensive. Edwards and Ross (1960), Ross and Edwards (1967), Christ (1960), Tennyson (1963) and Heller (1970) developed classifications based on the polymerization of these two different types of polyhedra to form a hierarchy of clusters, chains, sheets and frameworks of triangular and tetrahedral borate groups.…”

Section: Historical Backgroundmentioning

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: Historical Backgroundmentioning

confidence: 99%

The structure hierarchy hypothesis

Hawthorne

2014

Mineral. mag.

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“…There is a gradual condensation of the aluminosilicate tetrahedra in the crystallizing minerals with progressive crystallization, indicating that the bond topology of the resultant minerals is closely related to the crystallization process in basaltic magmas. In borate minerals, B may occur as (Bu 3 ) and (Bu 4 ) groups (u = O 2-, OH), and classifications by Edwards and Ross (1960), Ross and Edwards (1967), Christ (1960), Tennyson (1963) and Heller (1970) took into account the polymerization of these two different types of polyhedra. In structures such as sulphates, phosphates, arsenates and vanadates, systematic classifications were slower to arise.…”

Section: The Structure Hierarchy Hypothesismentioning

confidence: 99%

A bond-topological approach to theoretical mineralogy: crystal structure, chemical composition and chemical reactions

Hawthorne

2012

Phys Chem Minerals

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Here, I describe a theoretical approach to the structure and chemical composition of minerals based on their bond topology. This approach allows consideration of many aspects of minerals and mineral behaviour that cannot be addressed by current theoretical methods. It consists of combining the bond topology of the structure with aspects of graph theory and bond-valence theory (both long range and short range), and using the moments approach to the electronic energy density-of-states to interpret topological aspects of crystal structures. The structure hierarchy hypothesis states that higher bond-valence polyhedra polymerize to form the (usually anionic) structural unit, the excess charge of which is balanced by the interstitial complex (usually consisting of large low-valence cations and (H 2 O) groups). This hypothesis may be justified within the framework of bond topology and bond-valence theory, and may be used to hierarchically classify oxysalt minerals. It is the weak interaction between the structural unit and the interstitial complex that controls the stability of the structural arrangement. The principle of correspondence of Lewis acidity-basicity states that stable structures will form when the Lewis-acid strength of the interstitial complex closely matches the Lewis-base strength of the structural unit, and allows us to examine the factors that control the chemical composition and aspects of the structural arrangements of minerals. It also provides a connection between a structure, the speciation of its constituents in aqueous solution and its mechanism of crystallization. The moments approach to the electronic energy densityof-states provides a link between the bond topology of a structure and its thermodynamic properties, as indicated by correlations between average anion coordination number and reduced enthalpy of formation from the oxides for [6]

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“…Another attempt to systematize borates (including organic compounds) was undertaken by G. Heller [96]. It was based on the cation type and the number of boron atoms in the polyanion structural unit.…”

Section: Classificationmentioning

confidence: 99%

“…Isolated or bonded into chains and layers triborate groups of one BO 3 -triangle and two BO 4 -tetrahedra represent anions of all the hydrated Ca borates. In the anhydrous 3D borates, usually regarded as the end member of this series, the paired rings of two BO 3 -triangles and three BO 4 -tetrahedra are bonded into a framework by additional tetrahedra [96]. For this reason G. Christ and J. Clark emphasized the difference in the structure of anhydrous and hydrated borates and suggested the necessity of their independent analysis.…”

Section: Classificationmentioning

confidence: 99%

Crystal Chemistry of High-Temperature Borates

2020

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In recent years borate-based crystals has attracted substantial interest among the research community. The overall importance of this family of materials is reflected in miscellaneous articles and several reviews that have been published over the years. Crystalline borate materials exhibit numerous interesting physical properties, which make them promising for further practical applications. Diversity of functional characteristics results from their high structural flexibility caused in the linkage of planar/non–planar BO3 groups and BO4 tetrahedra, which can occur as isolated or condensed structural units. This report is a brief review on crystal chemistry and structure features of anhydrous/high-temperature borates. Polymorphism of boron-oxygen radicals has been considered basing on cations’ nature and synthesis conditions. Analysis of the laws governing borates structures and general principles of their systematics was discussed. As a result, an alternative classification of anhydrous compounds has been considered. It is based on four orders of their subdivision: (1) by the variety of anion formers, (2) by the cation charge, (3) by the N = NM:NB, i.e., ratio of metal atoms number to the ratio of boron atoms number (N-factor) value indicating the borate structural type (if it is known), (4) by the cation type and size.

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Darstellung und Systematisierung von Boraten und Polyboraten

Cited by 16 publications

References 124 publications

The structure hierarchy hypothesis

The structure hierarchy hypothesis

A bond-topological approach to theoretical mineralogy: crystal structure, chemical composition and chemical reactions

Crystal Chemistry of High-Temperature Borates

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