Structural Chemistry of Silicates: Structure, Bonding, and Classification

1 Introduction.- 1.1 Occurrence and Abundance of Silicon.- 1.2 Technical Importance of Silicon.- 1.3 Diversity of Silicon Compounds.- 2 Methods to Describe the Atomic Structure of Silicates.- 2.1 Model Representations of Silicate Structures.- 2.2 Treatment of Tetrahedrally Coordinated Cations in Silicates.- 3 Chemical Bonds in Silicates.- 3.1 The Silicon - Oxygen Bond.- 3.1.1 Coordination Numbers of Silicon.- 3.1.2 Bond Lengths and Bond Angles in Silicates Containing [SiO4] Tetrahedra (Tetraoxosilicates).- 3.1.2.1 Correlations Between Si-O Distance, Oxygen Coordination Number, and Bond Strength.- 3.1.2.2 Correlations Between Si-O Distance and Bond Angles.- 3.1.2.3 Correlations Between Si-O Distance, Oxygen Coordination Number, Bond Strength, and Si-O-Si Angle.- 3.1.2.4 Influence of Structural Disorder on Si-O Distances.- 3.1.2.5 Si-O-Si Angles.- 3.1.3 Bond Lengths and Bond Angles in Silicates Containing [SiO6] Octahedra (Hexaoxosilicates).- 3.1.4 The Nature of the Si-O Bond.- 3.1.4.1 The Ionic Model.- 3.1.4.2 The Covalent Model.- 3.1.4.3 Nonbonded Interactions.- 3.1.4.4 The Ionicity of the Si-O Bond.- 3.2 The Cation - Oxygen Bond, M-O, and Its Influence on the Si-O Bond.- 3.2.1 Electropositive Cations.- 3.2.2 Electronegative Cations.- 4 Crystal Chemical Classification of Silicate Anions.- 4.1 General Principles of the Classification.- 4.2 Parameters Used in the Crystal Chemical Classification of Silicate Anions.- 4.3 The Crystal Chemical System of Silicate Anions.- 4.4 Periodic Character of the Crystal Chemical Classification of Silicate Anions.- 5 Nomenclature and Structural Formulae of Silicate Anions and Silicates.- 5.1 Nomenclature.- 5.1.1 Chemical Nomenclature.- 5.1.2 Mineralogical Nomenclature.- 5.2 Structural Formulae.- 6 Crystal Chemical Classification of Silicates: General Part.- 6.1 Mixed-Anion Silicates.- 6.2 The Crystal Chemical System of Silicates.- 6.3 Further Subdivision of Silicates.- 6.3.1 Atomic Ratio Si: O of Silicate Anions.- 6.3.2 Degree of Chain Stretching.- 6.3.3 Silicate Anion Symmetry.- 6.3.4 Cation - Oxygen Polyhedra.- 6.4 Silicate Classification Procedure.- 6.5 Shortcomings of the Crystal Chemical Classification.- 7 Crystal Chemical Classification of Silicates: Special Part.- 7.1 Silicon Compounds with [SiO6] Octahedra (Hexaoxosilicates).- 7.2 Silicates Containing [SiO4] Tetrahedra (Tetraoxosilicates).- 7.2.1 Silicates with Edge-Sharing Tetrahedra.- 7.2.2 Silicates with Corner-Sharing Tetrahedra.- 7.2.2.1 Oligosilicates (Sorosilicates).- 7.2.2.2 Ring Silicates (Cyclosilicates).- 7.2.2.3 Single Chain Silicates (Monopolysilicates).- 7.2.2.4 Multiple Chain Silicates (Oligopolysilicates).- 7.2.2.5 Single Layer Silicates (Monophyllosilicates).- 7.2.2.6 Double Layer Silicates (Diphyllosilicates).- 7.2.2.7 Tectosilicates.- 7.2.2.8 Silicates with Interpenetrating Anions.- 7.3 Mixed-Anion Silicates.- 7.4 Estimated Frequency Distribution of Silicate Species.- 8 Other Classifications of Silicates.- 8.1 Early Classifications of Silicates.- 8.2 Rostov's Classification of Silicates.- 8.3 Zoltai's Classification of Silicates.- 8.4 Geometrical Classification of Tectosilicates.- 8.4.1 Connectedness.- 8.4.2 Secondary Building Units.- 8.4.3 Chain-Like Building Units.- 8.4.4 Layer-Like Building Units.- 8.4.5 Polyhedral Building Units Framework Density.- 8.4.6 Concluding Remarks.- 8.5 Silicate Classification Based on Non-Silicon Cation - Oxygen Bond.- 3.1.1 Coordination Numbers of Silicon.- 3.1.2 Bond Lengths and Bond Angles in Silicates Containing [SiO4] Tetrahedra (Tetraoxosilicates).- 3.1.2.1 Correlations Between Si-O Distance, Oxygen Coordination Number, and Bond Strength.- 3.1.2.2 Correlations Between Si-O Distance and Bond Angles.- 3.1.2.3 Correlations Between Si-O Distance, Oxygen Coordination Number, Bond Strength, and Si-O-Si Angle.- 3.1.2.4 Influence of Structural Disorder on Si-O Distances.- 3.1.2.5 Si-O-Si Angles.- 3.1.3 Bond Lengths and Bond Angles in Silicates Containing [SiO6] Octahedra (Hexaoxosilicates).- 3.1.4 The Nature of the Si-O Bond.- 3.1.4.1 The Ionic Model.- 3.1.4.2 The Covalent Model.- 3.1.4.3 Nonbonded Interactions.- 3.1.4.4 The Ionicity of the Si-O Bond.- 3.2 The Cation - Oxygen Bond, M-O, and Its Influence on the Si-O Bond.- 3.2.1 Electropositive Cations.- 3.2.2 Electronegative Cations.- 4 Crystal Chemical Classification of Silicate Anions.- 4.1 General Principles of the Classification.- 4.2 Parameters Used in the Crystal Chemical Classification of Silicate Anions.- 4.3 The Crystal Chemical System of Silicate Anions.- 4.4 Periodic Character of the Crystal Chemical Classification of Silicate Anions.- 5 Nomenclature and Structural Formulae of Silicate Anions and Silicates.- 5.1 Nomenclature.- 5.1.1 Chemical Nomenclature.- 5.1.2 Mineralogical Nomenclature.- 5.2 Structural Formulae.- 6 Crystal Chemical Classification of Silicates: General Part.- 6.1 Mixed-Anion Silicates.- 6.2 The Crystal Chemical System of Silicates.- 6.3 Further Subdivision of Silicates.- 6.3.1 Atomic Ratio Si: O of Silicate Anions.- 6.3.2 Degree of Chain Stretching.- 6.3.3 Silicate Anion Symmetry.- 6.3.4 Cation - Oxygen Polyhedra.- 6.4 Silicate Classification Procedure.- 6.5 Shortcomings of the Crystal Chemical Classification.- 7 Crystal Chemical Classification of Silicates: Special Part.- 7.1 Silicon Compounds with [SiO6] Octahedra (Hexaoxosilicates).- 7.2 Silicates Containing [SiO4] Tetrahedra (Tetraoxosilicates).- 7.2.1 Silicates with Edge-Sharing Tetrahedra.- 7.2.2 Silicates with Corner-Sharing Tetrahedra.- 7.2.2.1 Oligosilicates (Sorosilicates).- 7.2.2.2 Ring Silicates (Cyclosilicates).- 7.2.2.3 Single Chain Silicates (Monopolysilicates).- 7.2.2.4 Multiple Chain Silicates (Oligopolysilicates).- 7.2.2.5 Single Layer Silicates (Monophyllosilicates).- 7.2.2.6 Double Layer Silicates (Diphyllosilicates).- 7.2.2.7 Tectosilicates.- 7.2.2.8 Silicates with Interpenetrating Anions.- 7.3 Mixed-Anion Silicates.- 7.4 Estimated Frequency Distribution of Silicate Species.- 8 Other Classifications of Silicates.- 8.1 Early Classifications of Silicates.- 8.2 Rostov's Classification of Silicates.- 8.3 Zoltai's Classification of Silicates.- 8.4 Geometrical Classification of Tectosilicates.- 8.4.1 Connectedness.- 8.4.2 Secondary Building Units.- 8.4.3 Chain-Like Building Units.- 8.4.4 Layer-Like Building Units.- 8.4.5 Polyhedral Building Units Framework Density.- 8.4.6 Concluding Remarks.- 8.5 Silicate Classification Based on Non-Silicon Cation - Oxygen Polyhedra.- 9 General Rules for Silicate Anion Topology.- 10 Influence of Non-Tetrahedral Cation Properties on the Structure of Silicate Anions.- 10.1 Influence of Cation Properties on the Conformation of Unbranched Single Chain Anions.- 10.1.1 Conformation of Unbranched Silicate Single Chains.- 10.1.2 Qualitative Correlations Between Chain Conformation and Cation Properties.- 10.1.3 Semiquantitative Correlations Between Chain Conformation and Cation Properties.- 10.1.4 Crystallochemical Interpretation of the Correlations.- 10.1.4.1 Correlation Between Stretching Factor and Average Cation Electronegativity.- 10.1.4.2 Correlation Between Stretching Factor and Average Cation Valence.- 10.1.4.3 Correlation Between Stretching Factor and Average Cation Radius.- 10.1.4.4 Correlation Between Stretching Factor and Chain Periodicity.- 10.2 Influence of Cation Properties on the Shape of Unbranched Multiple Chain Anions.- 10.3 Influence of Cation Properties on the Shape of Branched Silicate Anions.- 10.4 Influence of Cation Properties on the Formation of Cyclic Silicate Anions.- 10.5 Influence of Cation Properties on the Shape of Single Layer Silicate Anions.- 10.5.1 Anhydrous Single Layer Silicates.- 10.5.2 The Shape of Silicate Anions in Anhydrous Silica-Rich Barium Silicates.- 10.5.3 Hydrous Single Layer Silicates.- 10.5.3.1 Kaolinite-Like and Mica-Like Arrangements.- 10.5.3.2 Strain Reduction Mechanisms in Cation-Poor Phyllosilicates.- 10.5.3.3 Strain Reduction Mechanisms in Cation-Rich Phyllosilicates.- 10.5.4 Comparison of Anhydrous and Hydrous Single Layer Silicates.- 10.6 Influence of Cation Properties on the Shape of Double Layer Silicate Anions.- 10.7 Influence of Cation Properties on the Shape of Silicate Frameworks.- 10.7.1 Silica and Clathrasils.- 10.7.2 Zeolites.- 10.7.3 Aluminosilicates M[(A1, Si)4O8]: Feldspars and Their Polymorphs.- 10.7.3.1 M[(AlSi3O8] Phases with M = Li, Na, K, Rb, Cs.- 10.7.3.2 M[Al2Si2O8] Phases with M = Mg, Ca, Sr, Ba.- 10.7.4 Aluminosilicates M[AlSi2O6].- 10.7.5 Aluminosilicates M[AlSiO4].- 10.7.6 Comparison of Framework Silicates.- 11 Conclusion.- 11.1 Correlation Between Classification Parameters and Cation Properties.- 11.2 Influence of Cation Radius on the Structure of Silicates.- 11.3 Characteristics of the Crystal Chemical Classification of Silicates.- References.- Appendices I-III.- Substance Index.- Formula Index.