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metal-organic compounds
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The title compound, [Sn6(C4H9)6(CH3COO)6O6]·C7H8, has one half-toluene molecule and one half-organotin molecule in the asymmetric unit. The latter is situated about an inversion centre and belongs to the class of hexameric monoorganooxotin carboxylates with a hexagonal prismatic or `drum-like' motif of the central tin–oxygen core. Two Sn3O3 rings in a flat-chair conformation are linked via six Sn—O bonds and six bridging acetate groups. All Sn atoms have approximate octahedral coordination geometry. The Sn—O bonds which are trans to the alkyl group are significantly shorter than the others. One butyl group is disordered over two different sites, with occupancies of 0.9:0.1. Very large atomic displacement parameters of the toluene molecule indicate an unresolvable disorder about the twofold axis.
inorganic compoundsOpen access
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The title compound, K2[SnCl3]Cl·H2O, is the prototype of some isostructural compounds of composition M2[SnX3]X·H2O (M = large monovalent cation; X = halogen). In comparison with a previous study based on photographic data [Kamenar & Grdenić (1962). J. Inorg. Nucl. Chem. 24, 1039–1045], its crystal structure has now been redetermined using CCD-based data in order to gain more accurate values for bond lengths and angles within the [SnCl3]− anion and to locate the H atoms. The [SnCl3]− anion has a trigonal–pyramidal shape and exhibits crystallographic mirror symmetry. With the exception of the K+ ion which is located on a general position, all other atoms are situated on crystallographic mirror planes. The coordination polyhedron of the cation may be described by means of nine atoms in the form of a monocapped square antiprism with seven typical K—Cl/O distances and two additional atoms at considerably longer distances. The positions of the H atoms of the water molecule (also lying on a crystallographic mirror plane) could be determined and confirm the existence of a bifurcated O—H
Cl hydrogen bond to neighbouring Cl atoms.
Cl hydrogen bond to neighbouring Cl atoms.inorganic compoundsOpen access
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The title compound, Li2[Sn(OH)6]·2H2O, is dimorphic. As for the previously described α-modification, the title β-modification crystallizes in the monoclinic system and contains the same primary building units, viz [Sn(OH)6]2− octahedra and [Li(μ2-OH)3(H2O)] tetrahedra. In contrast to the Sn—O bond lengths that are very similar in both modifications, the Li—O bond lengths differ significantly, in particular those involving the water molecule. In the new β-modification, the primary building units are linked into layers parallel to (010). The [Sn(OH)6]2− octahedra (-1 symmetry) form hexagonal nets and the [Li(μ2-OH)3(H2O)] tetrahedra are situated in between, with their apices in an alternating fashion up and down. O—HO hydrogen bonds between OH groups and water molecules exist within the layers as well as between them.
O hydrogen bonds between OH groups and water molecules exist within the layers as well as between them.inorganic compoundsOpen access
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The title compound, Ca[Sn(H2PO2)6], was formed after a few days when tin(II) fluoride was allowed to react with phosphinic acid at ambient conditions. The structure consists of chains of Ca2+ and Sn4+ cations in octahedral sites with -3 symmetry bridged by bidentate hypophosphite anions. The chains are hexagonally close packed along [001]. The discovery of the compound and the successful structure refinement provides strong evidence that an isostructural compound, originally described as the mixed-valence compound, Ge2[H2PO2]6 [Weakley (1983). J. Chem. Soc. Pak. 5, 279-281], must be reformulated as Ca[Ge(H2PO2)6].
metal-organic compoundsOpen access
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The title compound, [Sn(C4H9)2(CH3COO)2], was synthesized in order to study the influence of large organic groups on the molecular structure of diorganotin diacetates. The title compound exhibits the same structure type as other diorganotin(IV) diacetates characterized by an unsymmetrical bidentate bonding mode of the two acetate groups to tin. The influence of the t-butyl groups on this molecular structure is expressed in two significant differences: tin—carbon bond lengths are much more longer than in the other diacetates, as are the additional interactions of the acetate groups with the tin atom. Intermolecular interactions are restricted to C—HO ones similar to those in the other diacetates, giving rise to a chain-like arrangement of the molecules with the tin atoms and acetate groups in the propagation plane.
O ones similar to those in the other diacetates, giving rise to a chain-like arrangement of the molecules with the tin atoms and acetate groups in the propagation plane. organic compoundsOpen access
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The title compound (itaconic anhydride), C5H4O3, consists of a five-membered carbon–oxygen ring in a flat envelope conformation (the unsubstituted C atom being the flap) with three exocyclic double bonds to two O atoms and one C atom. In contrast to the bond lengths, which are very similar to those in itaconic acid in its pure form or in adducts with other molecules, the bond angles differ significantly because of the effect of ring closure giving rise to strong distortions at the C atoms involved in the exocyclic double bonds. In the crystal, C—HO interactions link the molecules, forming an extended three-dimensional network.
O interactions link the molecules, forming an extended three-dimensional network.
