Notizen: Bridging of Trigoldsulfonium Clusters by a Silver(I) Ion

1997 ◽  
Vol 52 (2) ◽  
pp. 301-304 ◽  
Author(s):  
Alexander Sladek ◽  
Hubert Schmidbaur
Keyword(s):  
Crystal Structure ◽  
Silver Atom ◽  
Metal Cluster ◽  
Phosphine Ligands ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Site Exchange ◽  
Mixed Metal Cluster ◽  
Short Contacts

Abstract Treatment of tris[(triphenylphosphine)gold(I)]-sulfonium tetrafluoroborate with AgBF4 (molar ratio 2:1) in tetrahydrofuran affords a hepta-nuclear mixed-metal cluster trication {[(Ph3P)6Au6AgS2](thf)}3+ as the tetrafluorobor­ate salt. The crystal structure of the compound has been determined by X-ray diffraction. The sil­ver atom is found in a bridging position between the two Au3S units with short contacts to both sulfur atoms and to three out of six gold atoms. The coordination sphere of the silver atom is complemented by a tetrahydrofuran molecule. In di(tri)chlorom ethane solutions there is rapid site exchange of the silver coordination as shown by virtual equivalence of the phosphine ligands on the NMR time scale at ambient temperature.

The synthesis and X-ray crystal structure of the mixed-metal cluster [Os8(CO)22(AuPPh3)2]

1983 ◽  
pp. 608 ◽  
Author(s):  
Brian F. G. Johnson ◽  
Jack Lewis ◽  
William J. H. Nelson ◽  
Paul R. Raithby ◽  
Maria D. Vargas
Keyword(s):  
Crystal Structure ◽  
Metal Cluster ◽  
X Ray ◽  
Mixed Metal ◽  
Mixed Metal Cluster

Singly Charged λ6Si-Silicate Anions with an SiF5C Skeleton: Syntheses and Crystal Structure Analyses of the Ionic Hexacoordinate Silicon Compounds [Me3NH][F5SiCH2NMe2H]·H2O and [Me3NH][F5SiCH2NMe2H]·H2O

2000 ◽  
Vol 55 (1) ◽  
pp. 60-64
Author(s):  
Melanie Pülm ◽  
Joachim Becht ◽  
Reinhold Tacke
Keyword(s):  
Crystal Structure ◽  
Lewis Acids ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Coordination Polyhedra ◽  
Silicon Compounds ◽  
X Ray ◽  
Distorted Octahedra ◽  
Singly Charged ◽  
Crystalline Hydrates

The zwitterionic λ5Si-tetrafluorosilicates F4SiCH2NMe2H (1) and F4SiCH2NMe3 (2) behave as Lewis acids and react with [Me3NH]F (molar ratio 1:1) in aqueous solution to yield the ionic λ6Si-pentafluorosilicates [Me3NH][F5SiCH2NMe2H] (3) and [Me3NH][F5SiCH2NMe3] (4), respectively. These hexacoordinate silicon compounds contain singly charged λ6Si-silicate anions ([F5SiCH2NMe2H]- , [F5SiCH2NMe3]- ) with an SiF5C skeleton. Compounds 3 and 4 were isolated as the crystalline hydrates 3·H2O (yield 80%) and 4·H2O (yield 82%) which were structurally characterized by single-crystal X-ray diffraction. The Si-coordination polyhedra in the crystals of 3·H2O and 4·H2O are slightly distorted octahedra

Darstellung und Kristallstruktur von K49Tl108 / Preparation and Crystal Structure of K49T1108

1993 ◽  
Vol 48 (8) ◽  
pp. 1035-1040 ◽  
Author(s):  
Gerhard Cordier ◽  
Volker Müller
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray

K49T1108 was prepared from the elements (molar ratio K: Tl = 1:2) at 700 K. The crystal structure was determined by single crystal X-ray diffraction methods (a = 1728.7(1) pm, Pm 3, Z = 1, R = 0.086). It contains T112 icosahedra and Tl12 truncated tetrahedra (Kasper polyhedra). 20 truncated tetrahedra form Tl84-polyhedra (Samson polyhedra) by sharing hexagonal faces. These polyhedra are connected by common edges. Folded Tl13-chains connect the icosahedra and the Samson polyhedra to a framework. The truncated tetrahedra are occupied by potassium atoms.

Synthesis and sintering of SiC under high pressure and high temperature

1999 ◽  
Vol 14 (3) ◽  
pp. 906-911 ◽  
Author(s):  
S. K. Bhaumik ◽  
C. Divakar ◽  
S. Usha Devi ◽  
A. K. Singh
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
High Pressure ◽  
Silicon Powder ◽  
Synthesis Temperature ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microscopic Studies ◽  
Simultaneous Synthesis

Starting from elemental powders, simultaneous synthesis and compaction of SiC were conducted at 3 GPa pressure and temperatures in the range 2100–2900 K. The sintered compacts were characterized by x-ray diffraction, microhardness measurements, and microscopic studies. The efficiency of formation of SiC was dependent on the particle size of the silicon powder, crystallinity of the reactant carbon, molar ratio of silicon and carbon, and synthesis temperature and time. Carbon in excess of the stoichiometric amount was required to obtain compacts free from residual silicon. The SiC samples, with a Si: C molar ratio 1: 1.05, prepared at 2100 K for 300 s had a density and hardness of 3.21 g/cm3 (98.8% of theoretical density) and 22 GPa, respectively. The crystal structure of the SiC depended on the synthesis temperature. Pure β–SiC in the temperature range 2100–2500 K, and a mixture of α– and β–SiC above 2500 K were obtained. The β–SiC was highly crystalline and nearly defect-free.

scholarly journals Tl2C2O4·H2C2O4: a new crystalline form of thallium(I) oxalate

2015 ◽  
Vol 70 (4) ◽  
pp. 249-252 ◽  
Author(s):  
Oscar E. Piro ◽  
Gustavo A. Echeverría ◽  
Ana C. González-Baró ◽  
Enrique J. Baran
Keyword(s):  
Crystal Structure ◽  
Oxalic Acid ◽  
Crystalline Form ◽  
Molar Ratio ◽  
Monoclinic Space Group ◽  
Acid Molecule ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxalate Anion ◽  
Ft Raman

AbstractThe title compound was prepared by reaction, in aqueous solution, of Tl2CO3 and H2C2O4·2H2O in a molar ratio of 1:2. Its crystal structure was solved by X-ray diffraction methods. It crystallizes in the monoclinic space group P21/a with Z = 2 molecules per unit cell. The oxalic acid molecule and the oxalate anion are planar, residing on crystallographic inversion centers, and linked to each other by strong O–H···O hydrogen bonds giving rise to a polymeric structure. The Tl(I) ion is in a distorted polyhedral coordination with nine neighboring O atoms, five of oxalate anions and four others of oxalic acid molecules. The FTIR and FT-Raman spectra of the compound were also recorded and are briefly discussed.

Filling up another Gap: Synthesis and Crystal Structure of Ba2H3I

2011 ◽  
Vol 66 (11) ◽  
pp. 1087-1091 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Title Compound ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths

Colorless and transparent single crystals of Ba2H3I were obtained by reacting Ba with dried and sublimed NH4I in a 4 : 1 molar ratio in silica-jacketed Nb ampoules at 1100 K for 13 h. The crystal structure of the title compound was determined and refined by means of single-crystal X-ray diffraction. Ba2H3I crystallizes in a stuffed anti-CdI2 structure isotypic to Sr2H3I in the space group P3̄m1 (no. 164) with the lattice parameters a = 451.86(12) and c = 811.84(23) pm. The structural results for Ba2H3I are consistent with bond lengths and coordination geometries of related binary and ternary hydrides

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