Helmut M. Haendler

Some reactions of tin (II) chloride in nonaqueous solution

Abstract Reactions of tin (II) chloride with a number of nitrogen and oxygen compounds in several nonaqueous solvents are reported. Compounds were prepared with tetra-substituted ammonium chlorides, pyridine, 2,2′-bipyridyl, pyridine-N-oxide, 8-quinolinol, dimethylsulphoxide, diphenyl-sulphoxide and 1,4-dioxane. Tin (II) chloride also reacts with methanol and ethanol in the presence of triethylamine to form tin (II) methoxide and tin (II) ethoxide. These alkoxides hydrolyse readily, and intermediate tin (II) oxide alkoxides are formed. Freshly prepared tin (II) methoxide reacts readily with hydroxylic compounds and offers interesting possibilities as a synthetic aid. Structural aspects of the compounds are discussed.

The crystal structure of copper bromide telluride

Abstract The crystal structure of CuBrTe has been determined. The compound is tetragonal with unit cell dimensions a = 16.417A, c = 4.711A, Z = 16, and space group I 4 1 / amd . Three-dimensional counterdiffraction intensity data (Mo K α) were refined with full-matrix least-squares to a conventional unweighted R of 0.066. The structure consists of infinite tellurium spirals with bromine tetrahedra interspersed. Two basic types of disordered copper atoms were found. One type is at the center of the bromine tetrahedra and has several possible locations for each atom. The other type of copper lies on two possible sites in a distorted tetrahedral environment with tellurium and two bromine atoms as nearest neighbors.

The crystal structure of copper bromide triselenide, CuBrSe3

Abstract The crystal structure of CuBrSe 3 has been determined. The compound is orthorhombic with unit cell dimensions a = 14.363 A, b = 4.488 A, c = 7.696 A, Z = 4, and space group Pmna . Three-dimensional counterdiffraction intensity data (Mo Kα ) were refined with block-diagonal and full-matrix least squares to a conventional unweighted R of 0.0515. The structure consists of six-membered selenium rings, in a chair-type configuration, separated in one axial direction by rows of bromine atoms and in the other by staggered layers of copper and bromine atoms. The rings are parallel to one another in rows along the c -direction, but the rows of rings alternate orientation in the a -direction.

The thermal decomposition of ammonium hexafluorogallate and ammonium hexafluoroindate. New crystalline forms of gallium fluoride and indium fluoride

Ammonium hexafluorogallate, (NH4)3GaF6, and ammonium hexafluoroindate, (NH4)3InF6, occur in two polymorphic forms, a low temperature tetragonal and a high temperature cubic form, which transform reversibly. They decompose on heating with an initial loss of 2 moles of ammonium fluoride, forming ammonium tetrafluorogaIlate, NH4GaF4, and ammonium tetra fluoroindate, NH4InF4. Further heating results in the gradual loss of ammonium fluoride; the final decomposition products are γ-gallium fluoride and γ-indium fluoride, new crystalline forms. These convert on further heating to the common hexagonal forms of the trifluorides. The structural relationship of the compounds are discussed and compared with those of the aluminum analogs.

The isostructural γ-sulfur phase of selenium-sulfur, SenS8−n

Abstract Two new selenium-sulfur species, Se 1.1 S 6.9 (yellow) and Se 3.7 S 4.3 (orange), have been isolated as single crystals, and the corresponding structures have been determined. The space group is P 2c, and the parameters are a = 8.34 A˚, b = 13.11 A˚, c = 9.30 A˚, β = 123.9° and a = 8.40 A˚, b = 13.26 A˚, c = 9.37 A˚, β = 124.5°, respectively. They are isostructural with γ-sulfur, having two distinct pairs of eight membered rings in the unit cell. The selenium and sulfur atoms appear scrambled throughout all atomic positions, but are not scrambled equally. When atomic site occupancy data are combined with other data from the literature, a wide compositional continuum of γ-sulfur isostructures is revealed that extends from γ-sulfur to SeS. It appears unlikely that selenium-sulfur crystals exist having the γ-sulfur structure with more than half the atoms as selenium.

The crystal and molecular structure of Bis( ortho -aminobenzoato)zinc(II), Zn(H 2 NC 6 H 4 COO) 2

Bis(ortho-aminobenzoato)zinc(II), Zn(H2NC6H4COO)2, is monoclinic, space group P21c, with a = 13.938(2) A, b = 5.207(1) A, c = 9.346(1) A, β = 108.37°, Z = 2. The structure was solved by direct and Fourier methods and refined to a final R of 0.047 based on 1198 observable reflections. The zinc is octahedrally coordinated, with four equatorial positions occupied by two amino nitrogen atoms and two carboxylate oxygen atoms such that both the nitrogen and oxygen atoms are in trans positions. The axial positions are occupied by two carbonyl oxygen atoms belonging to two other ligands not associated with the equatorial sites. The extreme insolubility of the compound may be accounted for not only by the two-dimensional polymeric network of carboxylate bridges between zinc atoms in the (100) plane, but also by the presence of hydrogen bonding between ligand molecules.

The thermal decomposition of nickel and zinc fluoride tetrahydrates

Abstract Nickel fluoride tetrahydrate, NiF2·4H2O, decomposes in three steps when heated, the products depending on the atmosphere in which the decomposition occurs. In dry air or in dry argon three moles of water are lost at about 125°, and the monohydrate, NiF2·H2O, is formed. At about 225°, the monohydrate loses water and hydrogen fluoride, and NiOHF·3NiF2 is formed. The latter compound loses an additional mole of hydrogen flouride at about 430°, and the final product is a mixture of nickel fluoride and nickel oxide in a 3:1 mole ratio. In the presence of water vapour the final decomposition product is solely nickel oxide; the other steps are the same. Zinc fluoride tetrahydrate loses four moles of water at temperatures above about 75°, forming anhydrous zinc fluoride.

The crystal and molecular structure of tris(ortho-aminobenzoato)aquoyttrium(III), Y(H2NC6H4COO)3 · H2O

Abstract Tris(ortho-aminobenzoato)aquoyttrium(III), Y(H2NC6H4COO)3 · H2O, crystallizes in the monoclinic space group, C2 c , with eight molecules in a unit cell of dimensions: a = 30.89(1) A, b = 9.09(1) A, c = 14.85(1) A, and β = 109.3(1)°. The structure was determined using three-dimensional X-ray diffraction data gathered on multiple-film equi-inclination, integrated Weissenberg, and precession photographs taken about two crystal axes. The structure, excluding the hydrogen atoms, was solved from Patterson and electron density maps and refined by least-squares methods to a final R of 0.081. The coordination about the yttrium atom is sevenfold, best described by a capped trigonal prism. Each ortho-aminobenzoate ligand acts as a bridging bidentate ligand, resulting in six ortho-aminobenzoate residues coupled to each yttrium atom. The water molecule occupies the seventh position. This bonding configuration generates a structure in which each yttrium atom in (100) is attached to two other yttrium atoms via carboxylate bridges to give parallel sets of polymeric chains coincident with (100). It is suggested that this polymeric character accounts for the extreme insolubility of Y(H2NC6H4COO)3 · H2O.

Synthesis of fluorometallates in methanol. The solid solution NH4MnF3 − NH4ZnF3

Abstract Solid solutions of anhydrous ammonium fluorometallates can be prepared from methanol solution by reaction of ammonium fluoride with a solution of mixed bromides, prepared by direct bromination of the metal mixture in methanol. Solid solutions in the series NH 4 MnF 3 - NH 4 ZnF 3 have been prepared and characterized. X-ray diffraction, magnetic susceptibility, thermal decomposition, and infrared spectra have been studied as functions of composition.

Nonaqueous Synthesis of a Highly Photochromic Tungstic Acid

Abstract A photochromic tungstic acid has been synthesized in nonaqueous media for the first time. The action of bromine on powdered tungsten metal, in methanol, produced a highly photochromic tungstic acid, WO3·0.75 H2O, in 93% yield. The material was much more photochromic than the previously known WO3·0.5 H2O, reversibly passing from white to dark blue by the action of ultraviolet light. The mechanism of the synthesis involves the solvent, methanol, producing by-products of methyl formate and organic bromides. An adsorbed organic compound, such as a normal alcohol, appears necessary for photochromism, and the material may be dispersed in thin films of plastic without loss of activity.