Search results for "Octahedron"

ChemInform Abstract: Crystal Structure of the Microwave Dielectric Resonator Ba2Ti9O20.

1983

A single-crystal X-ray study of dibarium nonatitanate, Ba2Ti9O20, yielded the triclinic space group P 1 with a=0.7471(1), b= 1.4081(2), c= 1.4344(2) nm, α=89.94(2)°, β= 79.43(2)°, γ= 84.45(2)°, V = 1.476 nm3 Z = 4, and Dx= 4.61 Mg/m3. A refinement of atomic coordinates and isotropic thermal parameters led to a residual of 0.03. The structure consists of hexagonally closest-packed layers of Ba and O atoms in the sequence (hch)3. All Ti atoms reside in octahedral interstices of this closest packing. The various Ti coordination octahedra share only edges and corners with each other. One-half of the Ba atoms is twelve-coordinated by oxygen atoms, the other half is eleven-coordinated.

ChemInform Abstract: Ferric Phosphite: Dimers of Face-Sharing Fe(III)O6 Octahedra. Crystal Structure Redetermination, Moessbauer Spectra, Magnetic Su…

2010

Deformation of the octahedral coordination of the Sb(III) atom in the structure of bis(1,2,4-triazolium) pentachloroantimonate(III) (C2H4N3)2[SbCl5]

2002

In the title compound the [SbCl 6] 3- octahedra show high variations in their Sb-Cl bond lengths and Cl-Sb-Cl angles. There are two crystallographically non-equivalent (C 2H 4N 3) + 1,2,4-triazolium cations in the crystal structure. They are located inside the cavities formed by the [{SbCl 5} 2-] n inorganic structure. The [{SbCl 5} 2-] n chains and (C 2H 4N 3) + cations are connected with each other by the N-H...Cl and C-H...Cl hydrogen bonds. Only two chloride atoms are involved in the N-H...Cl hydrogen bonds. The N-H...Cl interactions are responsible for the changing of geometries of Sb1-Cl2 and Sb1-Cl4 bonds and corresponding Cl-Sb-Cl angles. Their influence on the geometry of [SbCl 6] …

Syntheses, crystal structures and magnetic properties of di- and trinuclear croconato-bridged copper(ii) complexes

2002

The new croconato-bridged copper(II) compounds [Cu2(terpy)2(H2O)2(C5O5)](NO3)2·H2O (1) and [Cu3(phen)5(C5O5)2](CF3SO3)2 (2) (C5O52− = croconate, dianion of 4,5-dihydroxycyclopent-4-ene-1,2,3-trione; terpy = 2,2′:6′,2″-terpyridine; phen = 1,10-phenanthroline) have been prepared, and their crystal structures and variable temperature magnetic susceptibilities determined. The structure of complex 1 consists of croconato-bridged dinuclear [Cu2(terpy)2(H2O)2(C5O5)]2+ complex ions, nitrate counter ions and water of hydration. The croconato ligand exhibits an asymmetrical bis-bidentate coordination mode through four of its five oxygen atoms. The two crystallographically independent copper atoms hav…

XAFS STUDIES OF OCTAHEDRAL AMORPHOUS OXIDES

1993

The relationships between the structures of octahedral and tetrahedral amorphous oxides, studied by XAFS spectroscopy, are considered. It was found that a-WO3, a-MoO3, a-V2O5 thin films and glasses have strongly distorted, but well defined, oxygen octahedra, which are joined by vertices (a-WO3, a-MoO3) or by vertices and edges (a-V2O5), and form a random network. At the same time, a-IrO2 and a-NiO have less distorted oxygen octahedra, which form the rutile type and rock salt type nanocrystalline structures. The variation of the structure with the change of the metal valence is considered and the possibility of small radius polaron detection by XAFS is discussed.

N,N,N',N'‐Tetramethylguanidinium tetrachloroantimonate(III) at 295 and 92K

1999

The crystal structure of N,N,N',N'-tetramethylguanidinium tetrachloroantimonate(III), (C 5 H 14 N 3 )[SbCl 4 ], has been determined at 295 and 92 K. Each Sb atom is surrounded by six Cl atoms forming an irregular [SbCl 6 ] 3- octahedron. The octahedra are connected with each other in infinite zigzag chains. There is one crystallographically independent N,N,N',N'-tetramethylguanidinium cation in the crystal structure. It is linked to the [SbCl 6 ] 3- octahedra through N-H...Cl hydrogen bonds. The deformation of the octahedral coordination of the Sb III atom is related to the presence of N-H...Cl hydrogen bonds.

ChemInform Abstract: Crystal Structure and Magnetic Properties of α-Mn(H2PO2)2× H2O.

2010

Abstract The crystal structure of α-Mn(H2PO2)2·H2O has been refined from X-ray powder diffraction data. The cell is monoclinic (space group P21/c, Z − 4) with α = 7.8601(3) A , b = 7.4411(3) A , c = 10.7717(4) A and β = 102.859(2)°. The structure was refined with the Rietveld refinement principles, using as starting model the parameters of the presumably isostructural compound Zn(H2PO2)2·H2O. The structure can be described as being formed by dimeric entities Mn2O2 of edge-sharing manganese octahedra. Each group is linked through Mn-O-P-O-Mn bridges to four other groups, resulting in a three-dimensional network. The thermal variation in the susceptibility shows a sharp peak at T = 6.5 K and …

ChemInform Abstract: Synthesis and Characterization of Diorganotin(IV) Derivatives of 2- Mercaptopyridine and Crystal Structure of Diphenyl Pyridine-…

2010

Diorganotin(IV) derivatives of 2-mercaptopyridine (HSPy), R2Sn(SPy)2, R2SnCl(SPy) (R = Me, iPr, nBu, tBu, Cy, Ph) and Cy2SnBr(SPy), were obtained from R2SnX2 (X = Cl, Br) and NaSPy. Ph2SnCl(SPy) crystals, as determined by singlecrystal X–ray diffraction, are monoclinic in the space group P21/n. Tin forms with the bidentate SPy ligand a four–membered chelate ring with a short NSnS bite angle of 64.8(1)° leading to a heavily distorted trigonal–bipyramidal environment about tin. Apical Cl–Sn–N angle = 156.1(1)° equatorial C–Sn–C angle = 121.9(2)°. From 119Sn Mossbauer and IR data, analogous structures are inferred for the other solid compounds R2SnX(SPy), and distorted octahedral molecular str…

ChemInform Abstract: Ta1.09Fe2.39Te4, a New Non-Stoichiometric Ternary Tantalum Telluride.

2010

Abstract Ta1.09Fe2.39Te4 was prepared by chemical transport from the elements in sealed silica tubes in a temperature gradient from 700 to 600 °C. It crystallizes in the monoclinic space group P2/m with a = 6.162(2) A , b = 7.852(3) A , c = 7.250(3) A , β = 95.32(3)° and Z = 2 . Its structure can be derived from a hexagonal close packing of tellurium atoms with tantalum and iron atoms in octahedral voids and additional iron atoms in tetrahedral voids. The structure is closely related to the structures of MM'Te2 (MNb, Ta; M′Fe, Co, Ni) and MxFeγTe2 (MNb, x = 0.89, γ = 0.93; MTa, x = 0.77, γ = 0.90).

[Ag67(SPhMe2)32(PPh3)8]3+: Synthesis, Total Structure, and Optical Properties of a Large Box-Shaped Silver Nanocluster

2016

Engineering the surface ligands of metal nanoparticles is critical in designing unique arrangements of metal atoms. Here, we report the synthesis and total structure determination of a large box-shaped Ag67 nanocluster (NC) protected by a mixed shell of thiolate (2,4-dimethylbenzenethiolate, SPhMe2) and phosphine (triphenylphosphine, PPh3) ligands. Single crystal X-ray diffraction (SCXRD) and electrospray ionization mass spectrometry (ESI-MS) revealed the cluster formula to be [Ag67(SPhMe2)32(PPh3)8]3+. The crystal structure shows an Ag23 metal core covered by a layer of Ag44S32P8 arranged in the shape of a box. The Ag23 core was formed through an unprecedented centered cuboctahedron, i.e.,…