October 2000 issue
The title quaternary oxide, trisodium dicalcium tantalum hexaoxide, is isostructural with Li3Ni2TaO6, a partially ordered rock-salt phase. The Na, Ca and Ta atoms occupy octahedral sites in an orderly manner and form a cation-ordered superstructure.
A full single-crystal structure analysis of [Ba(OH)I(H2O)4] reveals intra- and intermolecular hydrogen bonding, leading to a three-dimensional network. The compound is an intermediate between BaI2 and the gel of Ba(OH)2(H2O)x.
electronic papers (inorganic compounds)
Caesium vanadium(V) selenite contains vertex-sharing layers of distorted VO6 octahedra, capped by pyramidal selenite groups. Interlayer caesium cations complete the structure, which is isostructural with M(VO2)3(SeO3)2 (M = NH4+, K+) and Cs(VO2)3(TeO3)2.
The title double salt was obtained from the reaction of Y(NO3)3 and K6[H4Co2Mo10O38]·5H2O at a pH of about 2.0. The [H6CoMo6O24]3− anion is a typical B-type Anderson-structure heteropolyanion.
electronic papers (metal-organic compounds)
The structure of the title compound comprises a zigzag polymer of alternating tetrakis(μ-carboxylato-O:O′)dicopper(II) and 2-aminopyrimidine units linked by axial Cu—N bonds, and the non-centrosymmetric structure has four unique (3-methoxyphenyl)acetate moieties.
In complexes of the ligand 3,5-bis(2-pyridinyl)-1,3,4-oxadiazole (pod), coordination is through one pyridine and one oxadiazole N atom, i.e. it behaves as a bidentate ligand. Octahedral coordination of the Cu or Ni metal atom in the title complexes, (I) and (II), respectively, is achieved by two pod ligands and two water molecules in axial positions.
The title ruthenium complex contains a monodentate (C4H9)PPh2 ligand coordinated by the P atom. Coordination about the metal centre is completed by a η6-p-cymene ligand and two Cl atoms.
Bridging by the two thiocyanate groups in centrosymmetric six-coordinate bis(diphenylthiourea)bis(thiocyanato)cadmium(II) dihydrate leads to the formation of eight-membered [Cd—SCN→Cd—SCN→] rings that are linked at the metal atom to furnish chains running parallel to the a axis.
In the title compound, the sodium ion is coordinated in a distorted octahedral manner by two carboxylate O atoms and two water O atoms. Each of these water molecules bridges two adjacent Na ions, resulting in two four-membered rings of the type Na–O–Na–O.
A pseudo-tetrahedral Ni complex has been formed as a result of incomplete bis-chelation of Ni2+ by L−. The dihedral angle at nickel is 68.8 (1)°. A trigonal–planar LiO3 coordination is formed, with Li—O distances of 1.801 (6), 1.825 (6) and 1.842 (6) Å.
The three title complexes, (I)–(III), are isomorphous and isostructural and have crystallographic D3 symmetry. The lanthanide metal ions are coordinated by nine O atoms in a skewed tricapped trigonal prismatic geometry.
Reaction of CuBr2 with 2,6-diaminopyridine in HBr solution leads to 3,5-dibromination of the pyridininium ring. The resultant cation was isolated as the [CuBr4]2− salt. The diaminodibromopyridinium ions are planar, while the CuII ions have a distorted compressed tetrahedral coordination with C2 symmetry.
The structure consists of C7H11N2+ cations and centrosymmetric [SnCl6]2− octahedra. The octahedral [SnCl6]2− anion is hydrogen bonded via trans-Cl atoms to pyridinium N atoms from two cations forming (C7H11N2)2[SnCl6] structural units.
The first RuIII–thz (thz is 1,3-thiazole) complex characterized via X-ray diffraction, mer-[RuCl3(C3H3NS)3], is a potentially cytostatic compound and consists of discrete complex molecules with an octahedral coordination sphere in which the metal centre is linked to three chloride ions and to three thz ligands through the N atoms. The compound was prepared from the reaction of K3RuCl6 and excess thiazole in MeOH. The Ru—Cl and Ru—N bond distances average 2.3462 (6) and 2.0851 (19) Å, respectively.
The structure of the title compound consists of β-[Mo8O26]4− polyanions and imidazolium cations. A γ→β conversion is produced in the presence of Cu(NO3)2·3H2O.
In the title complex, the Mn atom is coordinated by three N atoms and three O atoms from three pyridinecarboxylate ligands in a distorted octahedral geometry. One ligand is protonated and is hydrogen bonded to the hydroxide anion.
The title compound is a one-dimensional heterometallic coordination polymer of the zigzag-type with the molecular composition [(dmpda)Pt(isonic)2Cu(H2O)3](NO3)2, where dmpda is 2,2-dimethyl-1,3-propanediamine and isonic is isonicotinate. One Cu atom links two platinum complex molecules through coordination to two carboxylate groups from the two platinum complex units, and the polymer has repeat zigzag units in which the Cu—Pt—Cu angle is 64.9°.
The Fe atom in the low-temperature (173 K) structure of the title metal–organic chemical vapour deposition (MOCVD) precursor is octahedrally coordinated and the three chelate rings are found to be significantly non-planar, adopting a half-chair conformation with the Fe atom out of the plane. The structure exhibits only intramolecular C—H⋯O interactions.