Crystal structure of silver metagermanate, Ag2GeO3

The crystal structure of Ag2GeO3 was determined from laboratory X-ray powder diffraction data (Cu Kα1) using the Rietveld method. The title compound is orthorhombic with space group P212121, Z=4, unit-cell dimensions a=0.463 09(1) nm, b=0.713 93(2) nm, and c=1.040 79(3) nm, and V=0.344 10(2) nm3 . The final reliability indices were Rwp=5.58%, S=1.26, Rp=4.20%, RB=0.67% , and RF=0.35% . The GeO4 tetrahedra form infinite chains of [Ge2O6] along the a axis, with two tetrahedra per identity period of 0.463 nm. Individual chains are connected by Ag atoms, one-half of which are almost linearly coordinated by two O atoms and the rest are coordinated by three O atoms. The relatively short Ag-Ag distances of 0.299 to 0.339 nm indicate Ag(I)-Ag(I) interaction. This compound is isostructural with Ag2SiO3.

Packing modes of (R,R)-tartaric acid esters and amides

The molecular packing modes of a series of mono- and diamides of (R,R)-tartaric acid are discussed on the basis of their crystal structures. Derivatives include combinations of methylester, amide, N-methylamide and N,N-dimethylamide groups, both symmetrically and asymmetrically substituted. The symmetrically substituted derivatives do not utilize their C 2 symmetry in the crystal. The packing of primary tartramides seems to be driven by NH...O=C hydrogen bonds and supplemented by strong OH...O=C and weak NH...OH bonds. On the other hand, in derivatives containing methylester and/or methylamide groups OH...OH...O=C hydrogen-bond patterns seem to dominate. Types of aggregates, characteristic for the investigated derivatives, include cyclic dimers and ring systems analogous to the dimers, but formed by two different although complementary functional groups, as well as sets of chains aligned in a manner resembling the helical arrangement of peptides. The helices are formed along the screw axis with an identity period of approximately 5 Å. In tartramic acids, containing in one molecule both carboxyl and amide functions, in competition between the two groups to control the molecular arrangement, the latter dominates, unless it is N-substituted tartramide, in which case the carboxyl group predominates. Problems with packing, which occur in some of the structures owing to the steric bulk of the methyl groups, are overcome by changes in conformation (esters) or by co-crystallization with solvent water molecules (methylamides and dimethylamides). These derivatives are also more likely to crystallize with multiple asymmetric units.

Soft process for the intercalation of ammonium cations into vanadium oxide

A soft process for the intercalation of different ammonium cations into vanadium pentoxide was developed. By refluxing an aqueous solution containing ammonium, tetramethylammonium (CH3)4N+, and tetraethylammonium (C2H5)4N+with V2O5powders, intercalation compounds containing corresponding ammonium cations were obtained. The compound with aniline C6H5NH2was also synthesized by the same process. The compounds with (CH3)4N+, (C2H5)4N+, and also C6H5NH2had diffraction patterns consisting of very sharp00llines. The spacing for sandwiching the intercalates (the identity period), (CH3)4N+, (C2H5)4N+, and C6H5NH2, was 1.29, 1.31, and 1.39 nm, respectively.

Kupfer- und Goldkomplexe von Dithiocarbaminsäureestern. Strukturen von [CuCI(L1)3] · CH2Cl2, [AuCl(L1)2], [CuI(L1)(PPh3)]2 und [Cu2ICuIICl4(L2)2]n (L1 = N-Phenyl-S-methyldithiocarbaminsäureester, L2 = N,N-Dimethyl-S-methyldithiocarbaminsäureester) / Copper and Gold Complexes of Dithiocarbamate Esters. X-Ray Structures of [CuCl(L1)3] · CH2Cl2, [AuCl(L1)2], [CuI(L1)(PPh3)]2 and [Cu2ICuIICl4(L2)2]n (L1 = N-Phenyl-S-methyldithiocarbamate, L2 = N,N-Dimethyl-S-methyldithiocarbamate)

Reactions of N-phenyl-S-methyldithiocarbamate (L1) and N,N-dimethyl-S-methyldithio-carbamate (L2) with CuCl2, [Cu2I2(PPh3)3] and HAuCl4 yield the complexes [CuCl(L1)3] • CH2Cl2 (1), [AuCl(L1)2] (2), [CuI(L1)(PPh3)]2 (3) and [Cu2ICuIICl4(L2)2]n (4). Their structures have been determined by single crystal X-ray crystallography. 1 and 2 are monomeric, with Cu(I) tetrahedrally four-coordinate and Au(I) two-coordinate with an S-Au-S angle of 158.2(1)°. 3 is dimeric with a central CuI2Cu core, the Cu•••Cu distance of which [314.9(1) pm] is rather large. The mixed valence complex 4 has a chain structure with the identity period CuII(μ-Cl)2CuI(μ-S)2CuI(μ-Cl)2. CuI is in a tetrahedral, CuII in a square planar environment. The (μ-S)2 bridged CuI ••• CuI distance is only 259.1(1) pm. The structures of the CuX2Cu cores of 3 and 4 are mainly determined by steric interactions of the donor atoms within the coordination spheres of the metal centers.

Intercalation of mixed chloride–fluorides of antimony in graphite

The intercalation of SbCl4F and SbCl3F2 into graphite is described. The c-axis identity period, measured by (00/) x-ray diffraction, is 9.30, 12.69, and 16.04 Å for stages 1, 2, and 3, respectively, of SbCl4 F-intercalated graphite. The c-axis identity period for stage 1 SbCl4F-intercalated graphite is 8.85 Å. Mass spectroscopy shows that the molecule in SbCl4F-intercalated graphite is a (SbCl4F)4 tetramer. The molecule in SbCl3F2-intercalated graphite is a (SbCl3F2)4 tetramer. Mossbauer measurements show that Sb is in a 5 + state in SbCl4F-intercalated graphite.