J.Y. Le Marouille

About SnF2 stannous fluoride. I. Crystallochemistry of α-SnF2

Abstract The crystal structure of monoclinic stannous fluoride α-SnF 2 has been refined from single-crystal X-ray data. The unit cell contains four cyclic Sn 4 F 8 tetramers. The structure contains two types of Sn atoms: Sn(1) is surrounded tetrahedrally by three fluorine atoms and a lone pair, E , and Sn(2) is surrounded octahedrally by five fluorine atoms and a lone pair. The structure is examined within the framework of Galys and Browns models. Topological relationships to rutile are presented.

Ag3.6Mo9Se11: Premier compose´a`clusters Mo9 dans des motifs Mo9Se11

Abstract The synthesis, the crystal structure and the electrical properties of Ag 3.6 Mo 9 Se 11 are presented. The structure is orthorhombic (space group Cmcm ) and can be well described as a stacking of Mo 9 Se 11 units. The tridimensional arrangement of these units leaves a certain number of cavities in the chalcogen atom network. These cavities are partially occupied by silver atoms.

Stabilisation de l'acetylenedicarbaldehyde. preparation et structure de complexes acetylenedicarbaldehyde-cobaltcarbonyle.

Abstract The chemical stabilization of acetylenedicarbaldehyde ADCA by complexation is reported; the X-Ray structures of two complexes ADCA(Co)2L6 (L = CO, PPh3) show two conformers of the ADCA moiety.

Sulfur-containing carbene-metal compounds: General route from carbon disulfide manganese complexes; X-ray structure of 1,3-dithiol-2-ylidenemanganese(I) derivative

Abstract Chiral carbene-manganese(I) complexes have been synthesized by the cyclo-addition of dimethyl acetylenedicarboxylate to the coordinated CS 2 ligand in Mn(η 2 -CS 2 )(CO)(L)C 5 H 4 R (L = P(OMe) 3 ; PMe 2 Ph; PMe 3 ). Irrespective of the nature of the ligand L, these 1,3-dithiol-2-ylidenemanganese(I) complexes are stable towards isomerisation into heterometallocycles and exhibit low frequency carbonyl absorption bands in the infrared consistent with a strong electron releasing effect of the carbene ligand. The structure of Mn(CS 2 C 2 (CO 2 Me) 2 )(CO)(P(OMe) 3 )(C 5 H 5 ) has been determined by X-ray analysis of a suitable crystal. The molecule shows a carbene carbonmanganese bond C(7)Mn of length 1.876 A and a planar carbene which does not adopt the 1,3-dithiolium aromatic-ring geometry but contains a carboncarbon double bond, C(8)C(9), of length of 1.341 A. The CO 2 Me groups are out of the plane of the carbene ligand and two positions with equal occupancy are found for each oxygen atom O(3) and O(5) belonging to the CO groups.

Crystal structure and properties of the uranium chalcogenides α-US2 and α-USe2

The uranium chalcogenides ..cap alpha..-US/sub 2/ and ..cap alpha..-USe/sub 2/ crystallize in the tetragonal space group P4/ncc and not I4/mcm as previously reported. Their crystal structures have been determined from single-crystal X-ray diffraction data and refined to R = 0.041 and R = 0.034, respectively. Uranium atoms occupy two crystallographic sites: U(1) in (8f) and U(2) in (4c). The fourfold position, U(2), is incompletely filled with three uranium atoms which show a significant uniaxial delocalization. Properties are discussed in relation to this new crystal structure.

Préparation et structure cristalline d'un nouvel oxychlorure d'uranium: Le dioxypentachlorodiuranium, U2O2Cl5

The preparation of a new uranium oxychloride, U/sub 2/O/sub 2/Cl/sub 5/, is described. The compound is orthorhombic, Cmmm, with a = 8.431(3) A, b = 13.663(3) A, c = 4.106(2) A, Z = 2, Dm = 4.76 g cm/sup -3/, Dx = 4.81. The structure was solved from three-dimensional diffractometer data with Patterson and Fourier syntheses and full-matrix least-squares refinement. The final R value is 0.072 after absorption correction. The structure consists of (UCl/sub 4/2/Cl/sub 1/2/O/sub 2/2/)/sup infinity 2/ layers parallel to the (010) plane and linked in the b direction by bridging Cl atoms. The uranium atoms show noninteger formal valence while they are structurally equivalent; their coordination polyhedra are regular pentagonal bipyramids. Structural relationships among PaCl/sub 5/, ..beta..-U/sub 3/O/sub 8/, U/sub 2/O/sub 2/Cl/sub 5/, and RbIn/sub 2/F/sub 7/ are discussed in terms of MX/sub 7/ entities.

Le ligande isocyanure de benzoyle CNCOR. III: Spectres de vibrations et champ de force de valence du pentacarbonyle chrome(0) isocyanure de benzoyle: (CO)5CrCNCOC6H5

Abstract Infrared and Raman spectra of pentacarbonylchromium(0) benzoylisocyanide were recorded and interpreted. A valence force field is calculated with the help of isotopic derivatives frequencies. The benzoylisocyanide ligand is similar to the carbonyl ligand for chromium, this results in electronic delocalization all along the CNCO bonds. Comparisons with other ligands are made.