Note: Intro -- Molecular Clusters of the Main Group Elements -- Contents -- Preface -- List of Contributors -- 1 Theory and Concepts in Main-Group Cluster Chemistry -- 1.1 Introduction -- 1.1.1 Three-center Bonding in Boranes: Lipscomb's Equations of Balance -- 1.1.2 Polyhedral Skeletal Electron Pair Theory: The Wade-Mingos Rules -- 1.1.3 Aromaticity in Three-dimensional Clusters -- 1.1.3.1 From Polygonal Aromatics to Deltahedral Boranes -- 1.1.3.2 Interstitial Polygonal Aromatic-Deltahedral Borane Relationships -- 1.1.3.3 Aromaticity Evaluations of Three-dimensional Structures: Nucleus-Independent Chemical Shift (NICS) -- 1.1.3.4 Spherical Aromaticity -- 1.1.4 Bare Ionic Post-transition Metal Clusters: The Zintl Phases -- 1.1.5 Clusters of the Heavier Group 13 Metals -- 1.1.5.1 Apparently Hypoelectronic Deltahedra in Bare Clusters of Indium and Thallium: Polyhedra with Flattened Vertices -- 1.1.5.2 Organometallic Deltahedral Clusters of the Heavier Group 13 Metals and More Complicated Structures Derived from Deltahedra -- 1.1.5.3 Giant Aluminum Clusters with Shell Structures Consisting of Nested Polyhedra: Pieces of Icosahedral Quasicrystals -- 1.1.6 Conclusion and Outlook -- References -- 2.1 Homonuclear Boron Clusters -- 2.1.1 Introduction -- 2.1.2 General Principles and Systematic Naming -- 2.1.2.1 Structures and Bonding -- 2.1.3 Synthetic Methods -- 2.1.3.1 Diborane Pyrolysis -- 2.1.3.2 The Anionic Route -- 2.1.3.3 Platinum-catalyzed Dehydrocoupling -- 2.1.3.4 Cluster Expansion and Cluster Contraction Reactions -- 2.1.4 Chemistry of Selected Polyboranes -- 2.1.4.1 Chemistry of Triborane B(3)H(7) -- 2.1.4.2 Chemistry of Tetraboranes -- 2.1.4.2.1 arachno-Tetraborane(10) -- 2.1.4.2.2 Derivatives of nido-Tetraborane(8), B(4)H(8), and closo-Tetraborane(6), B(4)H(6) -- 2.1.4.3 Chemistry of Pentaborane(9) -- 2.1.4.4 Chemistry of Decaborane(14). , 2.1.5 Chemistry of Selected nido- and closo-Polyborane Anions -- 2.1.5.1 Chemistry of closo-B(6)H(6)(2-) -- 2.1.5.2 Chemistry of the Nonahydro-closo-nonaborate(2-) -- 2.1.5.3 Reaction of Decahydro-closo-decaborate(2-) -- 2.1.5.4 Chemistry of the nido-Decaborate B(10)H(13)(-) -- 2.1.5.5 Chemistry of Undecahydro-closo-undecaborate B(11)H(11)(2-) -- 2.1.5.6 Chemistry of the Dodecahydro-closo-dodecaborate -- 2.1.5.6.1 Protonation and Alkylation of B(12)H(12)(2-) -- 2.1.5.6.2 Halogeno-, Hydroxo-, Alkoxo- and Amine closo-dodecaborates -- 2.1.5.7 Chemistry of B(20)H(18)(2-) Anions -- 2.1.6 Substituted Neutral Polyboranes of Type B(y)X(y) -- 2.1.6.1 Overview -- 2.1.6.2 Structures -- 2.1.6.3 Synthesis -- 2.1.6.4 Reactions -- References -- 2.2 Boron Clusters in Medical Applications -- 2.2.1 Introduction -- 2.2.2 Dicarba-closo-dodecaborane, C(2)B(10)H(12), and Derivatives -- 2.2.2.1 Preparation and Reactions of C(2)B(10) Cage Compounds -- 2.2.2.2 Design and Classification of BNCT Reagents Containing C(2)B(10) Cages -- 2.2.2.3 Amino Acids -- 2.2.2.4 Nucleic Acid Precursors -- 2.2.2.5 DNA Binders -- 2.2.2.6 Porphyrins -- 2.2.2.7 Combination of C(2)B(10) and Gadolinium-containing Species -- 2.2.3 Derivatives of the nido-carborane C(2)B(9)H(12)(2-) -- 2.2.4 Application of C(2)B(10) for Drug Design -- 2.2.4.1 Properties of C(2)B(10) for Drug Design -- 2.2.4.2 Nuclear Receptor Ligands Bearing C(2)B(10) Cages -- 2.2.5 closo-Boranes -- 2.2.5.1 B(12)H(12)(2-) -- 2.2.5.1.1 Introduction of Heteroatoms as Substituents of B(12)H(12)(2-) -- 2.2.5.1.2 Reactivity of B(12)H(11)SH(2-) -- 2.2.5.1.3 Reactivity of B(12)H(11)OH(2-) -- 2.2.5.1.4 Reactivity of B(12)H(11)NH(2)(2-) -- 2.2.5.1.5 Analytical and Chromatographic Properties -- 2.2.5.1.6 Compounds for BNCT Derived from the B(12)H(12)(2-) Cluster -- 2.2.5.2 Azanonaboranes -- 2.2.6 Testing of Compounds for BNCT -- References. , 2.3 Clusters of the Heavier Group 13 Elements -- 2.3.1 Introduction -- 2.3.2 The Metal-Metal Bond -- 2.3.3 Boron Analogous Clusters of the Type [E(n)R(n)](x-) (x = 0, 1, 2) -- 2.3.3.1 Tetrahedral Cluster Compounds E(4)R(4) -- 2.3.3.1.1 Syntheses -- 2.3.3.1.2 Bonding -- 2.3.3.1.3 Structures -- 2.3.3.1.4 Physical Properties -- 2.3.3.1.5 Reactivity -- 2.3.3.2 Miscellaneous (Neutral and Anionic) Cluster Compounds E(6)R(6), E(8)R(8), E(9)R(9), E(12)R(12) -- 2.3.4 Metalloid (Neutral and Anionic) Clusters E(n)R(m< -- n) -- 2.3.4.1 Metalloid Clusters Al(n)R(m< -- n) -- 2.3.4.1.1 Al(7)(-), Al(12)(-), and In(12) Clusters -- 2.3.4.1.2 Al(14) Cluster -- 2.3.4.1.3 Al(69) and Al(77) Clusters -- 2.3.4.1.4 Hypothetical β-Aluminum -- 2.3.4.2 Metalloid Gallium Clusters Ga(n)R(m< -- n) and Related Indium Clusters -- 2.3.4.2.1 The Modifications of Elemental Ga -- 2.3.4.2.2 Ga(6) Cluster -- 2.3.4.2.3 Ga(8), Ga(9) and Related In Clusters -- 2.3.4.2.4 Ga(12) Clusters -- 2.3.4.2.5 Ga(10), Ga(13), and Ga(19) Clusters -- 2.3.4.2.6 Ga(18), Ga(22), and Ga(26) Clusters -- 2.3.4.2.7 The Ga(84) Cluster -- 2.3.5 Summary and Outlook -- References -- 2.4 Discrete and Extended Metal Clusters in Alloys With Mercury and Other Group 12 Elements -- 2.4.1 Introduction -- 2.4.2 Mercuride Clusters in Amalgams - Conflicts With Zintl's Concept? -- 2.4.2.1 General -- 2.4.2.2 Small Mercuride Clusters -- 2.4.2.3 Single "Mercuride" Ions? -- 2.4.2.4 Extended Anionic Partial Structures of Mercury -- 2.4.2.5 MHg(n) Clusters With High Coordination Numbers -- 2.4.2.6 NaK(29)Hg(48) A Complex Ternary Amalgam With Mercury Acting as a Pseudo Group 13 Element [9] -- 2.4.2.7 Electric and Magnetic Properties of Amalgams -- 2.4.3 Conclusions -- Acknowledgements -- References -- 2.5 Molecular Cages and Clusters of the Heavier Group 14 Elements (E = Si, Ge, Sn or Pb) of Formula E(n)R(m) (n m). , 2.5.1 Introduction -- 2.5.2 Silicon Species of Formula Si(n)R(m) (n m) -- 2.5.2.1 Dimers and Trimers -- 2.5.2.2 Tetramers -- 2.5.2.3 Hexamers and Octamers -- 2.5.3 Germanium Cages and Clusters Ge(n)R(m) (n m) -- 2.5.3.1 Dimers -- 2.5.3.2 Germanium Trimers -- 2.5.3.3 Germanium Tetramers -- 2.5.3.4 Germanium Hexamers, Octamers and Decamers -- 2.5.4 Tin Cages and Clusters and Sn(n)R(m) (n m) -- 2.5.4.1 Dimers, Trimers and Tetramers -- 2.5.4.2 Hexamers, Octamers and Decamers -- 2.5.5 Lead Clusters Pb(n)R(n) -- 2.5.6 Conclusion -- References -- 2.6 Homoatomic Cages and Clusters of the Heavier Group 15 Elements: Neutral Species and Cations -- 2.6.1 Introduction -- 2.6.2 Neutral Homonuclear Pnicogen Clusters -- 2.6.2.1 Structures of the Tetrahedral E(4) Cages -- 2.6.2.2 Bonding in P(4) -- 2.6.2.3 Larger P(n) Cages (n > -- 4) -- 2.6.3 Cationic Homonuclear Pnicogen Clusters -- 2.6.3.1 Overview -- 2.6.3.2 Reaction Media and Environment for Bi Cluster Syntheses -- 2.6.3.3 Structurally Characterized Bi Cations [42] -- 2.6.3.4 What About Gaseous P(n)(+) and As(n)(+) Cations? -- 2.6.3.5 The Stability of Hypothetical P(n)(+) and As(n)(+) Cations in Condensed Phases -- 2.6.4 Outlook -- Acknowledgement -- References -- 2.7 Cages and Clusters of the Chalcogens -- 2.7.1 The Elements -- 2.7.2 Homopolyatomic Cations -- 2.7.2.1 The 6π Aromatic Cations E(4)(2+) -- 2.7.2.2 Bonding in Hexanuclear Te(6)(4+) and Te(6)(2+) -- 2.7.2.3 Molecular Structures of Te(8)(4+) and E(8)(2+) -- 2.7.2.4 Larger Polycations and Polymers -- 2.7.3 Polychalcogenide Anions -- 2.7.3.1 Polytelluride Anions With Cluster-like Building Units -- 2.7.4 Summary and Outlook -- References -- 3.1 Alkali and Alkaline Earth Metal Suboxides and Subnitrides -- 3.1.1 Introduction -- 3.1.2 Alkali Metal Suboxides -- 3.1.3 Barium Suboxides -- 3.1.4 Alkaline Earth Metal Subnitrides. , 3.1.5 Chemical Bonding and Physical Properties -- References -- 3.2 Carboranes: From Small Organoboranes to Clusters -- 3.2.1 Introduction and Background -- 3.2.2 Monocarbaboranes -- 3.2.2.1 Non-classical Diboriranes -- 3.2.2.2 Non-classical Triboretanes -- 3.2.2.3 Non-classical Bicyclo[1.1.0]triboretanes -- 3.2.2.4 Derivatives of 1-Carba-closo-oligoborate Ions [CH(BH)(n)](-) -- 3.2.2.5 Carba-nido-tetraboranes(7) -- 3.2.2.6 1-Carba-arachno-pentaboranes(10) -- 3.2.3 Dicarbaboranes -- 3.2.3.1 Non-classical 1,3-Dihydro-1,3-diboretes -- 3.2.3.2 Non-classical 1,2-Diboretanylidenes (Boriranylideneboranes) -- 3.2.3.3 Non-classical 1,2-Diboretanes -- 3.2.3.4 Dicarba-closo-pentaboranes -- 3.2.3.5 Dicarba-arachno-pentaborane-dianions -- 3.2.3.6 Dicarba-nido-hexaboranes and Dicarba-closo-boranes -- 3.2.4 Tricarbahexaborane -- 3.2.4.1 2,3,5-Tricarba-nido-hexaboranes(7) -- 3.2.4.2 Dianions of 2,4,6-Tricarba-hypho-hexaborane -- 3.2.5 Tetracarba-nido-boranes -- 3.2.5.1 Tetracarba-nido-hexaboranes -- 3.2.5.2 Tetracarba-nido-octaboranes -- 3.2.5.3 Tetracarba-nido-decaboranes -- 3.2.6 Pentacarba-nido-hexaboranes -- 3.2.7 Hexacarbaboranes -- 3.2.8 Heterocarboranes -- 3.2.8.1 2,4,5-Azadicarba-nido-hexaboranes -- 3.2.8.2 2,4,5-Thiadicarba-nido-hexaborane -- 3.2.8.3 Nido- and Hypho-lithiacarboranes -- 3.2.9 Conclusions -- References -- 3.3 Heteropolyboranes With the Heavier Group 14 Elements -- 3.3.1 Introduction -- 3.3.2 Syntheses of Heteropolyboranes With Heavier Group 14 Elements -- 3.3.2.1 Twelve Vertex Closo-heteroboranes -- 3.3.2.2 Eleven Vertex Nido-heteroboranes -- 3.3.2.3 Smaller Heteropolyboranes -- 3.3.3 Adducts of Disila-closo-dodecaborane -- References -- 3.4 Borane Clusters with Group 15 and Group 16 Heteroatoms: Survey of Compounds and Structures -- 3.4.1 Introduction -- 3.4.2 Closo-Clusters -- 3.4.2.1 The cl-5 to cl-9 Families -- 3.4.2.2 The cl-10 Family. , 3.4.2.3 The cl-11 Family.