Chaouki Boudaren

Poly[[μ-aqua-tetraaquabis(μ-2-hydroxy-4-oxocyclobut-1-ene-1,3-diolato)strontium] hemihydrate].

In the title coordination polymer, {[Sr(C4HO4)2(H2O)5]·0.5H2O}n, the Sr2+ ion is coordinated by three monodentate hydrogensquarate (hsq) anions and six aqua ligands in a distorted SrO9 monocapped square-antiprismatic geometry. The hsq anions and water molecules bridge the metal ions into infinite sheets lying parallel to (100). The O atom of the uncoordinated water molecule lies on a crystallographic twofold axis. The packing is stabilized by numerous O—H⋯O hydrogen bonds.

A powder X-ray diffraction study of lead chloride oxalate Pb 2 Cl 2 (C 2 O 4 ): ab initio structure determination and thermal behavior

Mixed lead chloride oxalate, Pb 2 Cl 2 (C 2 O 4 ), has been obtained in a polycrystalline form in the course of a study on precursors of nanocrystalline PZT-type oxides. Its crystal structure has been solved ab initio from powder diffraction data collected using a monochromatic radiation from a conventional X-ray source. The symmetry is monoclinic, space group C 2/ m , the cell dimensions are a =5.9411(3) A, b =5.8714(4) A, c =9.4212(4) A, β=95.232(4)° and Z=2. The structure consists of a stacking of complex double sheets, built from lead polyhedra, parallel to (001) and connected together through oxalate groups. The lead atom is nine-fold coordinated by four O atoms from one bidentate and two monodentate oxalate groups and five Cl atoms. The polyhedron can be described as a highly distorted square antiprism mono-capped by a Cl atom. The thermal behavior of lead chloride oxalate, in vacuum and in air, is carefully described from temperature-dependent powder diffraction and thermogravimetric measurements. It is shown that reaction pathways are complicated by the identification of various oxide chloride phases.

Bis(cytosinium) aqua­penta­chlorido­indate(III)

The asymmetric unit of the title compound, (C4H6N3O)2[InCl5(H2O)], comprises two independent cytosinium cations and an aquapentachloridoindate anion. The InIII ion is in a slightly distorted octahedral coordination geometry. In the crystal, alternating layers of cations and anions are arranged along [010] and are linked via intermolecular N—H⋯O, O—H⋯Cl and N—H⋯Cl hydrogen bonds, forming sheets parallel to (001). Additional stabilization within these sheeets is provided by weak intermolecular C—H⋯O interactions.

Poly[1H-imidazol-3-ium [di-μ-nitrato-sodium]]

In the title compound {(C3H5N2)[Na(NO3)2]}n, the NaI ion is coordinated by eight O atoms from three bidentate nitrate anions and two O atoms from two monodentate nitrate anions, displaying a bicapped trigonal–prismatic geometry. The imidazolium cation is essentially planar (r.m.s. deviation for all non-H atoms = 0.0018 Å). In the crystal, the NaI ions are connected by bridging nitrate ligands, forming layers parallel to (010). The imidazolium cations are sandwiched between these layers. Weak C—H⋯O hydrogen bonds link the layers into a three-dimensional network. In addtion, π–π interactions between the imidazolium rings [centroid–centroid distance = 3.588 (3) Å] are observed.

(±)-Bis(1-carb-oxy-2-phenyl-ethanaminium) hexa-fluoro-silicate(VI).

The asymmetric unit of the title fluorosilicate salt, 2C9H12NO2 +·SiF6 2−, consists of a phenylalaninium cation and half of a fluorosilicate anion, the Si atom being located on an inversion center. In the crystal, all of the F atoms act as hydrogen-bond acceptors and link the cations through different graph-set motifs, forming layers developing parallel to (100).

catena-Poly[[{bis-[tetra-aqua-(2-hy-droxy-3,4-dioxocyclo-but-1-en-1-olato-κO)bariumstrontium(0.35/0.65)]di-μ-aqua}-bis-(μ-2-hy-droxy-4-oxocyclo-but-1-ene-1,3-diolato-κO:O)] monohydrate].

The title structure, {[Ba0.71Sr1.29(C4HO4)4(H2O)10]·H2O}n, is built from dimers of edge-sharing monocapped square antiprisms [(Ba/Sr)O3(H2O)6], in which barium and strontium are statistically disordered [ratio 0.353 (8):0.647 (8)] on the same crystallographic site. Such dimers are connected via bidentate hydrogen squarate groups [HC4O4]−, leading to chains that propagate along the b axis. Inter- and intramolecular O—H⋯O hydrogen bonds maintain the crystal packing through a three-dimensional network.

Anhydrous barium strontium oxalate

In the title compound, (Ba0.741Sr0.259)C2O4 or C2Ba0.741O4Sr0.259, the asymmetric unit consists of one disordered barium/strontium ion lying on a crystallographic twofold rotation axis and half of a centrosymmetric oxalate ion (one C and two O atoms). The crystal structure can be described as double parallel zigzag chains runnning along the c axis and linked together by additional monodentate oxalate-metal bonding. The distance between two chains is b/2. Each metal ion has six O-atom neighbours and they are linked together via the different coordination modes of the oxalate groups, resulting in the formation of a three-dimensional network.

A novel three-dimensional SrIIcoordination polymer based on benzene-1,2,4,5-tetracarboxylate: hydrothermal synthesis, crystal structure and spectroscopic and thermal studies

Coordination of the anions of benzenecarboxylic acids with metal cations leads to coordination polymers with various structural features. Very few examples of strontium-based structures have been reported. A new three-dimensional coordination polymer, namely poly[aqua(μ12-benzene-1,2,4,5-tetracarboxylato)distrontium(II)], [Sr2(C10H2O8)(H2O)]n, has been synthesized under hydrothermal conditions and characterized by thermal analysis, vibrational spectroscopy (Raman and IR), single-crystal X-ray diffraction and powder X-ray diffraction. The coordination geometries around the two independent SrII ions can be described as a distorted dodecahedron and a distorted monocapped square antiprism. The compound features a three-dimensional structure containing inorganic motifs, with two-dimensional layers connected through organic linkers, and possesses a topologic structure of a binodal (6,12) connected alb net with the Schläfli symbol {415}2{448.618}. The final product of thermal decomposition is strontium oxide (SrO).

catena-Poly[bis(1,3-benzo­thia­zol-3-ium) [[di­chlorido­anti­monate(III)]-di-μ-chlorido-μ-oxido-[chlorido­anti­monate(III)]-μ-chlorido]]

In the crystal, alternating layers and chains of the organic cations and inorganic anions are connected through an extensive three-dimensional network of N—H⋯Cl and C—H⋯Cl hydrogen bonds.π–π stacking interactions link the molecules within the layers and also link the layers together and reinforce the cohesion of the ionic structure.

Hydro­thermal synthesis and crystal structure of a new lanthanum(III) coordination polymer with fumaric acid

The title compound, poly[diaquatris(μ4-but-2-enedioato)(μ2-but-2-enedioic acid)dilanthanum(III)], [La2(C4H2O4)3(C4H4O4)(H2O)2]n, was synthesized by the reaction of lanthanum chloride pentahydrate with fumaric acid under hydrothermal conditions. The asymmetric unit comprises an LaIII cation, one and a half fumarate dianions (L 2−), one a half-molecule of fumaric acid (H2 L) and one coordinated water molecule. Each LaIII cation has the same nine-coordinate environment and is surrounded by eight O atoms from seven distinct fumarate moieties, including one protonated fumarate unit and one water molecule in a distorted tricapped trigonal–prismatic environment. The LaO8(H2O) polyhedra centres are edge-shared through three carboxylate bridges of the fumarate ligand, forming chains in three dimensions to construct the MOF. The crystal structure is stabilized by O—H⋯O hydrogen-bond interactions between the coordinated water molecule and the carboxylate O atoms, and also between oxygen atoms of fumaric acid