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  • Author: P. I. Rentzeperis x
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A bismuth oxide sulfate, [Bi1 – xCoxO]2(SO4)1 – x 0.14 ≤ x ≤ 0.18, was prepared by interacting CoSO4 with Bi2O3. Single crystals were obtained and investigated by X-ray diffraction. They are monoclinic, C2, a = 5.615(3) Å, b = 5.535(2) Å, c = 8.080(2) Å, β = 108.97(5)°, Z = 2,244 measured reflexions: R = 0.079. The structure consists of continuous [Bi1 – xCoxO]n fluorite-like layers separated by SO4 2− anions. It shows close structural similarity to the mineral nadorite, PbSbO2Cl and the already reported [Bi2CoO3]SO4 (Fanariotis and Rentzeperis, 1987).


The title compound, Cu[C6H18N4](PF6)2, is orthorhombic, with space group B2mb and Z = 4. The cell dimensions are: a = 7.362(1) Å, b = 14.708(5) Å and c = 15.551(6) Å. A total of 1623 independent reflections were measured with a SYNTEX P21 automatic diffractometer using Mo radiation. The structure was refined by full-matrix least-squares to a conventional R factor 0.0693 for 1560 unique reflections. The co-ordination around the central copper atom is octahedral with the copper atom 0.096(18) Å below the equatorial plane of the four nitrogen atoms of the ligand molecule. The Cu – N equatorial plane bond lengths have a mean value of 1.9815 Å. The remaining positions of the co-ordination octahedron are occupied by two fluorine atoms of the fluorophosphate groups. The Cu – F bonds have lengths of 2.5901 Å and 2.6014 Å.


The crystal structure of BiOCl has been redetermined with 3570 observed reflections of which 174 were unique measured on a computer controlled Philips PW 1100 single crystal diffractometer. The structure belongs to the tetragonal space group P4/nmm and the cell constants, obtained by a least-squares calculation from direct θ-value measurements on the diffractometer, are a = 3.8870(5) and c = 7.3540(5) Å.

The positional and thermal parameters, with anisotropic temperature factors, were refined by full-matrix least-squares calculations to a final R = 9.17%.

Each Bi atom is eight-coordinated by 4 O and 4 Cl atoms at distances of 2.316 Å and 3.059 Å respectively thus forming a decahedron. The faces of the decahedron are 2 rectangles (O–O–O–O and Cl–Cl–Cl–Cl) with sides 3.487 Å and 8 isosceles triangles (four O–Cl–O and four Cl–O–Cl) with sides O–Cl 3.249 Å and O–O or Cl–Cl 3.487 Å.

The decahedra are linked to each other by a common O–Cl edge along the a and b axes in infinite layers.


The crystal structure of (triphenylphosphine)(nitrosyl)(O-cyclopentyldithiocarbonate)nickel, Ni(NO)(PPh3)(S2COC5H9), has been determined from three-dimensional X-ray diffraction data, collected on a computer-controlled Philips PW1100 single-crystal diffractometer (2894 observed reflections). The crystals are monoclinic, space group P21/c, with a = 10.416(1), b = 9.890(1), c = 23.876(4) Å, β = 97.84(1)° and Z = 4. The structure was solved by direct phase determination with MULTAN and refined by least-squares calculations to a final R = 0.038 (Rw = 0.040). The Ni atom is fourfold coordinated by two S, one P and one N atom, which form a strongly distorted tetrahedron. The xanthate ligand acts as bidentate, while the group NiNO is slightly bent. The Ni – S distances are practically equal, 2.328(1) – 2.329(1) Å, and the Ni – P and Ni – N distances are 2.240(1) and 1.650(4) Å respectively. In the nitrosyl ligand the N – O distance is 1.136(5) Å, while in the xanthate and the triphenylphosphine ligands the determined distances and angles are as expected. The crystal cohesion may be attributed to normal van der Waals forces.


The crystal structure of the title compound has been determined from three-dimensional X-ray diffraction data for 2997 observed unique reflections [I > 2 σ(I)].

The crystals are triclinic, space group P [unk], with: a = 10.328(6), b = 10.868(4), c = 10.243(3) Å, α = 117.18(2), β = 96.26(3), γ = 96.48(3)°, V = 999.26 Å3 and Z = 2. The structure was solved by the heavy-atom method and refined by least-squares to a final R = 0.030 (Rw = 0.037).

Antimony is in pseudooctahedral coordination with the two axial positions occupied by chlorine atoms [Sb – Cl 2.510(2), 2.550(1) Å] and three of the equatorial apices occupied by the carbonyl oxygen [Sb – O 2.110(4) Å], a hydrazide nitrogen [Sb – N 2.202(5) Å] and a pyridine nitrogen [Sb – N 2.326(4) Å] of the organic ligand, which acts as a tridentate chelate. The fourth apex is occupied by the non-bonding electron pair of Sb(III). The molecules, which are essentially planar due to the extended fused ring system formed by the organic ligand, are held together by van der Waals forces. The IR and UV spectra are in accordance with the established geometrical features of the structure.