NaIn(CrO4)2·2H2O,the first indium(III) member of the kröhnkite family

Sodium indium(III) chromate(VI) dihydrate, NaIn(CrO₄)₂·2H₂O, synthesized from an aqueous solution at room temperature, is the first indium(III) member of the large family of compounds with kröhnkite [Na₂Cu^II(S^VIO₄)₂·2H₂O]‐type chains. The crystal structure is based on infinite octa­hedral–tetra­hedral [In(CrO₄)₂(H₂O)₂]⁻ chains along [010], linked via charge‐balancing Na⁺ cations. The slightly distorted InO₄(H₂O)₂ octa­hedra are characterized by a mean In—O distance of 2.125 Å. The CrO₄ tetra­hedra are strongly distorted (mean Cr—O = 1.641 Å). The Na atom shows an octa­hedral coordination, unprecedented among compounds with kröhnkite‐type chains. The NaO₆ octa­hedra share opposite edges with the InO₄(H₂O)₂ octa­hedra to form infinite [001] chains. The hydrogen bonds are of medium strength. NaIn(CrO₄)₂·2H₂O belongs to the structural type F2 in the classification of Fleck, Kolitsch & Hertweck [Z. Kristallogr. (2002), 217 , 435–443], and is isotypic with KAl(CrO₄)₂·2H₂O and MFe(CrO₄)₂·2H₂O (M = K, Tl or NH₄). All atoms are in special positions except one O atom.     

Monoclinic Cu3(SeO3)2Cl2: an oxo­halide with an unusual CuO4Cl trigonal–bipyramidal coordination

In single crystals of a new monoclinic (C2/m) form of tricopper(II) diselenium(IV) dichloride hexa­oxide, Cu₃(SeO₃)₂Cl₂, the Se atom is in the 4i position, while the two Cu atoms are in 2a and 4i positions. The structure is based on layers of CuO₄Cl trigonal bipyramids, CuO₄ square planes and SeO₃E tetra­hedra. The Cu polyhedra are connected by edge‐ and corner‐sharing to form [010] chains and these chains are bridged by the Se atoms to form (001) layers. The compound is isostructural with Cu₃(TeO₃)₂Br₂.     

Dilead(II) trimercury(II) tetraoxide chromate(VI), Pb2(Hg3O4)(CrO4)

Pb₂(Hg₃O₄)(CrO₄) consists of [CrO₄]²⁻ tetra­hedra, linear O—Hg—O dumbbells and divalent Pb atoms in [3+5]‐coordination. The HgO₂ dumbbells are condensed into [Hg₃O₄]²⁻ units and can be regarded as a section of the HgO structure. The [Hg₃O₄]²⁻ complex anions are connected by inter­stitial Pb²⁺ ions, while the [CrO₄]²⁻ tetra­hedra are isolated.     

[{Cu(phen)2}(μ‐malato){Cu(phen)(NO3)}](NO3)·4H2O: malate acting as a tetra­dentate and dibridging ligand in a dinuclear copper complex

The crystal structure of the title compound, μ‐2‐hydroxy­butane­dioato‐1κ²O⁴,O^4′:2κ³O¹,O²,O⁴‐nitrato‐2κO‐tris­(1,10‐phen­anthroline)‐1κ⁴N,N′;2κ²N,N′‐dicopper(II) nitrate tetra­hydrate, [Cu₂(C₄H₃O₅)(NO₃)(C₁₂H₈N₂)₃](NO₃)·4H₂O, contains an unsymmetrical dinuclear copper complex with Cu(phen)₂ and Cu(phen)(NO₃) moieties (phen is 1,10‐phenanthroline) bridged by a malate (2‐hydroxy­butane­dioate) ligand, which acts as a double‐bridging and tetra­dentate ligand. As a result of this double‐bridging action, especially the direct coordination of the O atom of one carboxyl­ate group of malate to the two Cu atoms, the Cu⋯Cu distance is only 4.199 (1) Å and the two phen planes are roughly parallel [the shortest inter­planar distance is 3.28 (1) Å], exhibiting an obvious intra­molecular π–π stacking inter­action.     

Octa­hedral–tetra­hedral framework structures of InAsO4·H2O and PbIn(AsO4)(AsO3OH)

Indium arsenate(V) monohydrate, InAsO₄·H₂O, (I), crystallizes in the structure type of MnMoO₄·H₂O. The structure is built of In₂O₈(H₂O)₂ dimers (mean In—O = 2.150 Å) corner‐linked to slightly distorted AsO₄ tetra­hedra (mean As—O = 1.686 Å). The linkage results in a three‐dimensional framework, with small voids into which the apical water ligand of the InO₅(H₂O) octa­hedron points. The hydrogen bonds in (I) are of medium strength. Lead(II) indium arsenate(V) hydrogen arsenate(V), PbIn(AsO₄)(AsO₃OH), (II), represents the first reported lead indium arsenate. It is characterized by a framework structure of InO₆ octa­hedra corner‐linked to AsO₄ and AsO₃OH tetra­hedra. The resulting voids are occupied by Pb₂O₁₀(OH)₂ dimers built of two edge‐sharing highly distorted PbO₆(OH) polyhedra (mean Pb—O = 2.623 Å). The compound is isotypic with PbFe^III(AsO₄)(AsO₃OH). The average In—O bond length in (II) is 2.157 Å. In both arsenates, all atoms are in general positions.     

Two new non‐centrosymmetric lithium salts of glycine: bis(glycine) lithium chromate monohydrate and bis(glycine) lithium molybdate

In bis­(glycine) lithium chromate monohydrate {systematic name: poly[aquadi‐μ‐glycinato‐μ‐tetra­oxochromato(VI)‐dilithium(I)]}, [CrLi₂(C₂H₅NO₂)₂O₄(H₂O)]_n, (I) (space group P2₁2₁2₁), and bis­(glycine) lithium molybdate {systematic name: poly[di‐μ‐glycinato‐μ‐tetra­oxomolybdato(VI)‐dilithium(I)]}, [Li₂Mo(C₂H₅NO₂)₂O₄]_n, (II) (space group P2₁), all atoms are located on general positions. The crystal structure of (I) is characterized by infinite chains of corner‐sharing [LiO₄] tetra­hedra, which are connected by glycine mol­ecules to form layers. [CrO₄] tetra­hedra are attached to the [LiO₄] tetra­hedra. Compound (II) contains dimers of [LiO₄] tetra­hedra which are connected by [MoO₄] tetra­hedra to form chains, which are in turn connected by glycine mol­ecules to form double layers.     

Poly[bis(N‐methylformamide)tetra‐μ‐thiocyanato‐manganese(II)mercury(II)]

The title complex, [MnHg(NCS)₄(C₂H₅NO)₂]_n, consists of slightly distorted MnN₄O₂ octa­hedra and HgS₄ tetra­hedra. Each Mn^II cation is bound to four N atoms of the NCS groups and two O atoms of the N‐methyl­formamide (NMF) ligands in a cis configuration. Each Hg^II cation is coordinated to four S atoms of NCS groups. Each pair of Mn^II and Hg^II cations is connected by an –NCS– bridge, forming an infinite three‐dimensional –Mn—NCS—Hg– network.     

An extended two‐dimensional copper–molybdate compound with mixed dicarboxyl and organodiamine ligands

The title complex, poly[di‐μ₃‐oxo‐hepta‐μ₂‐oxo‐tetra­oxo­bis(1,10‐phenanthroline)‐μ₄‐terephthalato‐dicopper(II)­tetra­molybdate(VI)], [Cu₂Mo₄(C₈H₄O₄)O₁₃(C₁₂H₈N₂)₂], represents a novel two‐dimensional copper–molybdate compound with mixed ligands. Tetra­nuclear molybdenum oxide clusters are joined through corner‐sharing into a ribbon‐like chain, with [Cu(phen)]²⁺ (phen is 1,10‐phenanthroline) complexes grafted onto either side. The terephthalate ligand lies about an inversion centre and links these chains to form a layer via Cu—O and Mo—O bonds. Face‐to‐face π–π stacking inter­actions between adjacent phen ligands stabilize the structure.     

Three oxo complexes with a tetra­nuclear [Cu4(μ2‐Cl)6(μ4‐O)] unit

The three title compounds, namely 4‐phenyl‐1H‐imidazolium hexa‐μ₂‐chloro‐chloro‐μ₄‐oxo‐tris­(4‐phenyl‐1H‐imidazole‐κN¹)­tetra­copper(II) monohydrate, (C₉H₉N₂)[Cu₄Cl₇O(C₉H₈N₂)₃]·H₂O, hexa‐μ₂‐chloro‐μ₄‐oxo‐tetra­kis­(pyridine N‐oxide‐κO)tetra­copper(II), [Cu₄Cl₆O(C₅H₅NO)₄], and hexa‐μ₂‐chloro‐tetra­kis(2‐methyl‐1H‐imidazole‐κN¹)‐μ₄‐oxo‐tetra­copper(II) methanol trisolvate, [Cu₄Cl₆O(C₄H₆N₂)₄]·3CH₄O, exhibit the same Cu₄OCl₆ framework, where the O atom at the centre of an almost regular tetra­hedron bridges four copper cations at the corners. This group is in turn surrounded by a Cl₆ octa­hedron, leading to a rather globular species. This special arrangement of the Cu^II cations results in a diversity of magnetic behaviours.     

Unusual O‐coordination of caffeine in tetra­kis(μ‐3,5‐dinitro­benzoato‐κ2O:O′)bis­[(caffeine‐κO)copper(II)]

The title compound {systematic name: tetra­kis(μ‐3,5‐dinitro­benzoato‐κ²O:O′)bis­[(3,7‐dihydro‐1,3,7‐trimethyl‐1H‐purine‐2,6‐dione‐κO²)copper(II)]}, [Cu₂(C₇H₃N₂O₆)₄(C₈H₁₀N₄O₂)₂], consists of paddle‐wheel dimeric tetra­kis(μ‐3,5‐dinitro­benzoato‐κ²O:O′)dicopper(II) units with O‐coordinated caffeine mol­ecules in both apical positions. The entire dimeric mol­ecule lies on a tetra­gonal inversion axis, and thus one nitro­benzoate anion with one Cu atom in a special position belong to the independent part of the mol­ecule. The caffeine ligand bonded to the Cu atom is disordered on a local twofold non‐crystallographic axis coincident with the axis. A π–π stacking inter­action is observed between the caffeine rings and adjacent symmetry‐related benzene rings of the 3,5‐dinitro­benzoate anions.     

BaY2Si3O10: a new flux‐grown trisilicate

BaY₂Si₃O₁₀, barium diyttrium trisilicate, is a new silicate grown from a molybdate‐based flux. The structure is based on zigzag chains, parallel to [010], of edge‐sharing distorted YO₆ octa­hedra, linked by horseshoe‐shaped trisilicate groups and Ba atoms in irregular eight‐coordination. The layered character of the structure is caused by a succession of zigzag chains and trisilicate groups in planes parallel to (01). The Ba atoms occupy narrow channels extending parallel to [100]. The mean Y—O, Si—O and Ba—O bond lengths are 2.268, 1.626 and 1.633, and 2.872 Å, respectively. The two symmetry‐equivalent terminal SiO₄ tetra­hedra in the Si₃O₁₀ unit adopt an eclipsed conformation with respect to the central SiO₄ tetra­hedron; the Si—O—Si and Si—Si—Si angles are 136.35 (9) and 96.12 (4)°, respectively. One Ba, one Si and two O atoms are located on mirror planes; all remaining atoms are in general positions. The geometry of isolated trisilicate groups in inorganic compounds is briefly discussed.     

Bis(iminodiethylenedi­ammonium) di‐μ5‐hydrogen­phosphato‐penta­molybdate(VI) tetra­hydrate

The crystal structure of the title compound, (C₄H₁₅N₃)₂[Mo₅O₁₅(HPO₄)₂]·4H₂O, is made up of [Mo₅O₁₅(HPO₄)₂]⁴⁻ clusters, iminodiethylenediammonium cations and solvent water mol­ecules. The [Mo₅O₁₅(HPO₄)₂]⁴⁻ cluster, with approximate C₂ symmetry, can be considered as a ring formed by five distorted edge‐ and corner‐sharing MoO₆ octa­hedra, capped on both poles by a hydro­phosphate tetra­hedron. There exist N—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds between the organic ammonium groups and the clusters, with inter­atomic N⋯O distances ranging from 2.675 (3) to 2.999 (3) Å, and C⋯O distances ranging from 3.139 (5) to 3.460 (5) Å.     

New triple molybdates Cs3LiCo2(MoO4)4 and Rb3LiZn2(MoO4)4, filled derivatives of the Cs6Zn5(MoO4)8 type

Two new isotypic triple molybdates, namely tri­cesium lithium dicobalt tetra­kis­(tetra­oxo­molybdate), Cs₃LiCo₂(MoO₄)₄, and tri­rubidium lithium dizinc tetra­kis­(tetra­oxo­molybdate), Rb₃LiZn₂(MoO₄)₄, crystallize in the non‐centrosymmetric cubic space group I3d and adopt the Cs₆Zn₅(MoO₄)₈ structure type. In the parent structure, the Zn positions have 5/6 occupancy, while they are fully occupied by statistically distributed M²⁺ and Li⁺ cations in the title compounds. In both structures, all corners of the (M_2/3Li_1/3)O₄ tetra­hedra (M = Co and Zn), having point symmetry , are shared with the MoO₄ tetra­hedra, which lie on threefold axes and share corners with three (M,Li)O₄ tetra­hedra to form open mixed frameworks. Large alkaline cations occupy distorted cubocta­hedral cavities with symmetry. The mixed tetra­hedral frameworks in the structures are close to those of mayenite (12CaO·7Al₂O₃) and the related compounds 11CaO·7Al₂O₃·CaF₂, wadalite (Ca₆Al₅Si₂O₁₆Cl₃) and Na₆Zn₃(AsO₄)₄·3H₂O, but the terminal vertices of the MoO₄ tetra­hedra are directed in opposite directions along the threefold axes compared with the configurations of Al(Si)O₄ or AsO₄ tetra­hedra. The cation arrangements in Cs₃LiCo₂(MoO₄)₄, Rb₃LiZn₂(MoO₄)₄ and Cs₆Zn₅(MoO₄)₈ repeat the structure of Y₃Au₃Sb₄, being stuffed derivatives of the Th₃P₄ type.     

An X‐ray powder investigation of catena‐poly[copper(II)‐di‐μ‐chloro‐κ41:2Cl‐μ‐1,5‐dimethyl‐1H‐tetra­zole‐κ2N3:N4]

The crystal structure of the polymeric title complex, [CuCl₂(C₃H₆N₄)]_n, has been solved from laboratory X‐ray powder diffraction data collected at room temperature. The structural model obtained was refined with the Rietveld method using geometric soft restraints. There are two Cu atoms, two Cl atoms and one 1,5‐dimethyl­tetra­zole ligand in the asymmetric unit. Both Cu atoms lie on inversion centres and adopt essentially elongated octa­hedral coordination. Within the octa­hedra, the elongated axial positions are occupied by Cl atoms, while two Cl and two N atoms (N3 and N4 of the tetra­zole ring) are in equatorial sites. Each Cl atom forms an asymmetric bridge between neighbouring Cu atoms, which are also bridged via the N3—N4 bond of the tetra­zole ring. These bridges result in the formation of polymeric chains, running along the a axis, with weak C—H⋯Cl hydrogen bonds crosslinking the chains.     

RbCrIII(C2O4)2·2H2O,Cs2Mg(C2O4)2·4H2O and Rb2CuII(C2O4)2·2H2O: three new complex oxalate hydrates

Rubidium chromium(III) dioxalate dihydrate [di­aqua­bis(μ‐oxalato)­chromium(III)­rubidium(I)], [RbCr(C₂O₄)₂(H₂O)₂], (I), and dicaesium magnesium dioxalate tetrahydrate [tetra­aqua­bis(μ‐oxalato)­magnesium(II)­dicaesium(I)], [Cs₂Mg(C₂­O₄)₂(H₂O)₄], (II), have layered structures which are new among double‐metal oxalates. In (I), the Rb and Cr atoms lie on sites with imposed 2/m symmetry and the unique water molecule lies on a mirror plane; in (II), the Mg atom lies on a twofold axis. The two non‐equivalent Cr and Mg atoms both show octahedral coordination, with a mean Cr—O distance of 1.966 Å and a mean Mg—O distance of 2.066 Å. Dirubid­ium copper(II) dioxalate dihydrate [di­aqua­bis(μ‐oxalato)­copper(II)­dirubidium(I)], [Rb₂Cu(C₂O₄)₂(H₂O)₂], (III), is also layered and is isotypic with the previously described K₂‐ and (NH₄)₂Cu^II(C₂O₄)₂·2H₂O compounds. The two non‐equivalent Cu atoms lie on inversion centres and are both (4+2)‐coordinated. Hydro­gen bonds are medium‐strong to weak in the three compounds. The oxalate groups are slightly non‐planar only in the Cs–Mg compound, (II), and are more distinctly non‐planar in the K–Cu compound, (III).     

(2‐Methyl­quinolin‐8‐olato)­iron(III) and ‐copper(II) complexes

The crystal structures of tris(2‐methyl­quinolin‐8‐olato‐N,O)­iron(III), [Fe­(C₁₀­H₈­NO)₃], (I), and aqua­bis(2‐methyl­quinolin‐8‐olato‐N,O)­copper(II), [Cu­(C₁₀­H₈NO)₂­(H₂O)], (II), have been determined. Compound (I) has a distorted octahedral configuration, in which the central Fe atom is coordinated by three N atoms and three O atoms from three 2‐methylquinolin‐8‐olate ligands. The three Fe—O bond distances are in the range 1.934 (2)–1.947 (2) Å, while the three Fe—N bond distances range from 2.204 (2) to 2.405 (2) Å. In compound (II), the central Cu^II atom and H₂O group lie on the crystallographic twofold axis and the coordination geometry of the Cu^II atom is close to trigonal bipyramidal, with the three O atoms in the basal plane and the two N atoms in apical positions. The Cu—N bond length is 2.018 (5) Å. The Cu—O bond length in the basal positions is 1.991 (4) Å, while the Cu—O bond length in the apical position is 2.273 (6) Å. There is an intermolecular OW—H?O hydrogen bond which links the mol­ecules into a linear chain along the b axis.     

Dipotassium tetra­chromate(VI), K2Cr4O13

The structure of dipotassium tetra­chromium(VI) trideca­oxide, K₂Cr₄O₁₃, has been determined from single‐crystal X‐ray data collected at 173 (2) K on a racemically twinned crystal with monoclinic Pc space‐group symmetry. The structure is composed of discrete [Cr₄O₁₃]²⁻ zigzag chains held together by the charge‐balancing potassium ions. The conformations adopted by the tetra­chromate anion in alkali metal salts and Cr₈O₂₁ are different and can be divided into three categories.     

Bis(2,9‐dimethyl‐1,10‐phenanthroline‐κ2N,N′)copper(I) hydrogen squarate hemihydrate

In the crystal structure of the synthetically prepared title compound, [Cu(C₁₄H₁₂N₂)₂](C₄HO₄)·0.5H₂O or [Cu(dmphen)₂](HSq)·0.5H₂O (dmphen is 2,9‐dimethyl‐1,10‐phenanthroline or neocuproine and HSq is hydrogen squarate), the Cu^I centre has distorted tetra­hedral coordination geometry comprised of four N atoms from two bidentate dmphen ligands. The squarate monoanions form a ten‐membered dimer, graph set R₂²(10), linked by two strong inter­molecular O—H⋯O hydrogen bonds. These squarate dimers are linked into chains that propagate along the [100] direction. An extensive three‐dimensional network of C—H⋯O hydrogen bonds and π–π inter­actions is responsible for stabilization of the crystal structure.     

Rubidium dimolybdate,Rb2Mo2O7, and caesium dimolybdate,Cs2Mo2O7

The crystal structures of dirubidium hepta­oxodimolybdate, Rb₂Mo₂O₇, and dicaesium hepta­oxodimolybdate, Cs₂Mo₂O₇, in the space groups Ama2 and P2₁/c, respectively, have been determined for the first time by single‐crystal X‐ray diffraction. The structures represent two novel structure types of monovalent ion dimolybdates, A₂Mo₂O₇ (A = alkaline elements, NH₄, Ag or Tl). In the structure of Rb₂Mo₂O₇, Mo atoms are on a twofold axis, on a mirror plane and in a general position. One of the Rb atoms lies on a twofold axis, while three others are on mirror planes. Two O atoms attached to the Mo atom on a mirror plane are located on the same plane. Rubidium dimolybdate contains a new kind of infinite Mo–O chain formed from linked MoO₄ tetra­hedra and MoO₆ octa­hedra alternating along the a axis, with two terminal MoO₄ tetra­hedra sharing corners with each octa­hedron. The chains stack in the [001] direction to form channels of an approximately square section filled by ten‐coordinate Rb ions. Seven‐ and eight‐coordinate Rb atoms are located between chains connected by a c translation. In the structure of Cs₂Mo₂O₇, all atoms are in general positions. The MoO₆ octa­hedra share opposite corners to form separate infinite chains running along the c axis and strengthened by bridging MoO₄ tetra­hedra. The same Mo–O polyhedral chain occurs in the structure of Na₂Mo₂O₇. Eight‐ to eleven‐coordinate Cs atoms fill the space between the chains. The atomic arrangement of caesium dimolybdate has an ortho­rhom­bic pseudosymmetry that suggests a possible phase transition P2₁/c→Pbca at elevated temperatures.     

Proton‐stabilized three‐dimensional anionic framework in H[Zn6O2(BO3)3]

A three‐dimensional anionic framework built up from [ZnO₄] tetra­hedra and planar [BO₃] groups, stabilized by H atoms, has been found for hydrogen zinc oxide borate, H[Zn₆O₂(BO₃)₃]. Boron and one of the borate O atoms are on 18e (2) positions. Triple units of [ZnO₄] tetra­hedra sharing a common oxygen vertex on a 12c (3) site and strong asymmetrical linear hydrogen bonds with the H atom [on a 12c (3) position] disordered over a twofold axis are specific structural features of this zincoborate. There is evidence that the reported Zn₄O(BO₃)₂ [Harrison, Gier & Stuky (1993). Angew. Chem. Int. Ed. Engl. 32 , 724–726] corresponds to this structure.