Structural Chemistry of Layer-Type Phases

This monograph is intended to give the reader an appreciation of the wealth of phases, elements and inorganic compounds, which crystallize in layer-type or two­ dimensional structures. Originally this work was planned as a short review article but the large number of phases made it grow out to the size of a book. As is evident from the arrangement of the chapters our point of view was gradually transmuting from geometric to chemical. Moreover, the decision about the compounds that should be discussed was taken only during the course of the work, as is partly evident from the sequence of the references. For chemical or geometrical reason we have included also certain layered chain and molecular structures as well as some layered structures whose layers are linked by hydrogen bonds, thus are in fact three-dimensional. Instead of writing only a review with pseudo-scientific interpretations that later turn out to be wrong anyway we thought it more profitable to include the crystallographic data which are scattered in various original articles and hand books but never in one single volume. We have transcribed many of the data in order to make them correspond with the standard settings of the International Tables for X-Ray Crystallography. The figures are consistent with the data given in the tables. We apologize for errors and hope that their number is at a reasonably low level in spite of the time pressure.

I. Introduction and Definition.- II. Geometrical Derivation of Simple Layer-Type Structures.- 1. Coordination Numbers 9 and 8.- 2. Coordination Number 6: Trigonal Prism.- 3. Coordination Number 6: Octahedron.- 4. Coordination Number 4: Tetrahedron.- 5. Coordination Number 3: Trigonal Pyramid and Triangle.- III. Repartition of the Layer Structures.- IV. Discussion of Special Compounds.- 1. Compounds with Coordination Number 2.- a. AuI.- b. HgCl2.- c. HgBr2.- 2. Compounds with Coordination Number 3.- a. Sassolite B(OH)3.- b. Metaboric Acid HB02.- c. The B2S3 Structure.- d. The BCl3 Structure.- e. Graphite.- f. Boron Nitride.- g. Non-symmetrical Graphite Analogs, B2O.- h. Graphite Intercalation Compounds.- ?. Metal—Graphite Compounds.- ?. Graphite Salts.- 3. Compounds with Lone-Pair Cations (CN 3 ?6).- A. Phosphorus-Group Chalcogenides.- a. M2X3 Compounds with CN3.- b. Claudetite As2O3(h).- c. Orpiment As2S3.- d. As2Te3.- e. Kermesite Sb2S2O.- f. Getchellite AsSbS3.- g. Wolfsbergite-Type Compounds.- h. Livingstonite HgSb4S8.- i. CuTe2Cl (see Appendix).- B. Group V Elements and Isoelectronic Compounds.- a. The Arsenic Structure.- b. Superstructures Derived from the As Structure: GeTe, SnP3.- c. The Black Phosphorus and SnS Structure.- d. Hittorf’s Phosphorus.- e. Yellow PbO (Massicot).- f. Red PbO (Litharge).- g. Red SnO.- C. Various Compounds with s2 Cations.- a. Na2PbO2, LiBiO2, NaAs02 , . . ..- b. Lanarkite Pb2O(SO4).- c. Pb3(PO4)2(r).- d. SbPO4 and Related Phases.- e. Tellurite ?-TeO2.- f. 2TeO2·HN03.- g. Mixed TeIVOxides: Te2O5, H2Te2O6 and Te4O9.- h. Li2TeO3.- i. A Layered Sulfate, (IO)2SO4.- j. SnCl2.- k. Tl Chalcogenides Tl2X and Tl4X3.- 4. MX and MX2: Phases with Low Coordination Number.- a. In and Tl Monohalides and Alkali Hydroxides.- b. LiOH and Related Structures.- c. CuTe.- d. ?-NiTe.- e. Tetrahedral MX2 Structures (HgI2, AlPS4, GaPS4, GeS2).- 5. Polycationic Tetrahedral Layer Structures.- a. GeAs2-Type Compounds.- b. Layer-Type Group III Monochalcogenides and Group IV Monopnictides.- 6. Compounds with Polycationic Layers.- 7. Compounds with d8 Cations in Square-Planar Coordination.- a. PdS2 and PdPS.- b. Pd3(PS4)2.- c. AuTe2Cl.- d. AuCl3 and AuBr3.- e. AuSe (see Appendix).- 8. Oxides with Cation-Coordination Numbers 4 ?6.- a. P2O5.- b. The d0 Transition-Element Oxides and Related Hydroxides.- C . Tc2O7.- d. Re2O7.- e. MoO3 and Related Phases.- f . MoO3·2H2O and MoO3·H2O.- g . Mo18O52.- h. Layered Vanadium Oxyhydroxides.- i. V2O5.- 9. Close-Packed Structures with Group II and III Cations in Tetrahedral and Octahedral Coordination.- 10. Layer Compounds with B Metal Cations in Octahedral Coordination.- a. Non-Transition-Element CdI2-Type Chalcogenides.- b. Tetradymite (Bi2Te2S)-Type Compounds.- c. Layer Structures Based on NaCl—CdI2-Type Mixtures.- d. Tetradymite-Bismuth Composites.- 11. Transition-Element Compounds with Octahedral Cation Coordination.- a. Smythite Fe3S4.- b. (Fe,Ni)3Te2(h).- c. Pt2Sn3.- d. The Structures of PtTe (ZrCl), Pt3Te4 and Pt2Te3.- e. The FePS3 and the FePSe3 Structures.- f. CdI2-Type Transition-Element Chalcogenides.- g. The NbTe2 Structure.- h. Calaverite, Krennerite and Sylvanite.- i. PtBi2(h2).- j. Pt4PbBi7, MoTe2(h) and WTe2.- k. ReSe2 and TcS2.- 12. Group V and VI Dichalcogenides with Trigonal-Prismatic Cation Coordination.- 13. Compounds with Cation Coordination Number ?8.- a. Layer-Type Rare-Earth Polytellurides.- b. PdBi2(h).- c. The ZrSe3 Structure.- d. The HfTe5 Structure.- e. TaSe3.- f. NbSe3.- 14. Mixed-Anion Compounds MXY.- a. The PbFCl (Matlockite) Structure.- b. The SmSI Structure.- c. The ?-ZrNCl Random Structure.- d. The FeOCl and the ?-FeO(OH) Structure.- e. The AlOCl Structure.- f. The InTeCl Structure.- 15. Layer-Type Dihalides.- a. Halides with Trigonal-Prismatic Cation Coordination.- b. CdCl2- and Cdl2-Type Halides.- c. Cr and Cu Dihalides.- d. The Brucite-Type Hydroxides.- e. Mixed Hydroxyhalides.- f. Composite Layer Structures Derived from Brucite.- g. White Lead Pb(OH)2·2PbCO3.- h. Composite Layer Structures with Incommensurate Sublattices.- i. The Composite Layer Structure of Lithiophorite.- 16. MX3 Halides.- a. The PuBr3 Structure.- b. Rare-Earth Hydroxychlorides.- c. CdCl2-/CdI2-Type Derivatives (TiCl3, BiI3, AlCl3, CrCl3).- d. MoCl3.- e. The NbS2Cl2 Structure.- f. Nb3Cl8, Nb3Br8, NbCl4.- g. Al(OH)3.- h. Rhenium Trihalides.- i. The AsBr3 Structure.- j. Group III Halides (AlBr3, GaCl3, InI3).- 17. Layer-Type Halides of Composition MX4, MX5 and MX6.- a. The UBr4 Structure.- b. The ThI4 Structure.- c. SrCl2·2H2O and BaCl2·2H2O.- d. The ZrCl4 Structure.- e. The SnF4 Structure.- f. UO2(OH)2 and UO2F2.- g. WO2Cl2 and WO2I2.- h. The NbI5 Structure.- i. Triclinic UCl5.- j. The ?-WCl6 Structure.- k. Cr(OH)3·3H2O.- 18. Layered Silicates Derived from Brucite and Bayerite.- References.- Mineral Name Index.- Formula Index.