Ce2[MoO5][MoO4] and Ce5[MoO4]8: Two New Cerium Oxomolybdates, Each Exhibiting a Special Structural Feature

2011 ◽  
Vol 66 (8) ◽  
pp. 763-770
Author(s):  
Tanja Schustereit ◽  
Thomas Schleid ◽  
Ingo Hartenbach

Ce2[MoO5][MoO4] crystallizes monoclinically in space group P21/c (a = 2241.98(9), b = 712.95(3), c = 2044.19(8) pm, β = 116.936(2), Z = 16). Besides eight crystallographically different Ce3+ cations with coordination numbers ranging from seven plus one to ten, its structure contains two isolated oxomolybdate(VI) species, namely [MoO4]2− tetrahedra and [MoO5]4− trigonal bipyramids and square pyramids. The oxygen polyhedra around the Ce3+ cations build up a three-dimensional ∞3 {[Ce2O9]12−} network by vertex-, edge-, and face-connections with the Mo6+ cations residing in tetrahedral, square-pyramidal, and trigonal-bipyramidal voids therein. Ce5[MoO4]8 also crystallizes monoclinically in space group P21/c (a = 1133.14(5), b = 1704.96(7), c = 1406.21(6) pm, β = 90.749(2)° Z = 4). In its structure eight isolated [MoO4]2− tetrahedra are present, which display an overall negative charge of −16. To maintain electroneutrality, mixed-valency of the five crystallographically independent cerium cations must be considered. A thorough bond-valence analysis reveals cerium at the Ce1 site as tetravalent, while the other four cerium cations prove to be trivalent. The polyhedra around all cerium cations form chains with a V-shaped profile along [100] via vertex-, edge-, and face-connections to result in a sawblade pattern. These chains are interlocked into sheets parallel to the (001) plane and linked by the Mo6+ cations to form a three-dimensional network.

2012 ◽  
Vol 68 (4) ◽  
pp. i23-i23 ◽  
Author(s):  
Abdelghani Oudahmane ◽  
Malika El-Ghozzi ◽  
Daniel Avignant

Single crystals of Ca5Zr3F22, pentacalcium trizirconium docosafluoride, were obtained unexpectedly by solid-state reaction between CaF2and ZrF4in the presence of AgF. The structure of the title compound is isotypic with that of Sr5Zr3F22and can be described as being composed of layers with composition [Zr3F20]8−made up from two different [ZrF8]4−square antiprisms (one with site symmetry 2) by corner-sharing. The layers extending parallel to the (001) plane are further linked by Ca2+cations, forming a three-dimensional network. Amongst the four crystallographically different Ca2+ions, three are located on twofold rotation axes. The Ca2+ions exhibit coordination numbers ranging from 8 to 12, depending on the cut off, with very distorted fluorine environments. Two of the Ca2+ions occupy interstices between the layers whereas the other two are located in void spaces of the [Zr3F20]8−layer and alternate with the two Zr atoms along [010]. The crystal under investigation was an inversion twin.


IUCrData ◽  
2021 ◽  
Vol 6 (8) ◽  
Author(s):  
Tim Peppel ◽  
Martin Köckerling

The solvated title salt, (C8H15N2)[NiBr3(P(C6H5)3)]·0.5C4H10O, was obtained in the form of single crystals directly from the reaction mixture. The molecular structure consists of separated 1-butyl-3-methylimidazolium cations, tribromido(triphenylphosphane)nickelate(II) anions and half a solvent molecule of 1-butanol, all connected via multiple hydrogen contacts to form a three-dimensional network. The co-crystallized 1-butanol molecule is disordered and adopts two orientations. The central C—C bonds of both orientations are located on an inversion centre (Wyckoff site 2b of space group P21/n). Thereby, each orientation has again two orientations with the OH group being located either on one or the other side of the C4 alkyl chain. The dried solvent-free compound exhibits a relatively low melting point (m.p. = 412 K).


Author(s):  
Takeshi Oishi ◽  
Keisuke Fukaya ◽  
Takaaki Sato ◽  
Noritaka Chida

In the fused tetracyclic system of the title compound, C29H36O9, the five-membered dioxolane ring adopts a twist conformation; the two adjacent C atoms deviate alternately from the mean plane of the other three atoms by −0.252 (6) and 0.340 (6) Å. The cyclohexane, cyclohexene and central cyclooctane rings show chair, half-chair and boat-chair forms, respectively. There are three intramolecular C—H...O interactions supporting the molecular conformation, with one S(6) and two S(7) graph-set motifs. In the crystal, intermolecular O—H...O hydrogen bonds connect the molecules into a helical chain running along the c-axis direction, generating a C(7) graph-set motif. The chains are further linked by intermolecular C—H...O interactions to construct a three-dimensional network. There is no valid C—H...π interaction.


Author(s):  
Anjapuli Ponnuvel ◽  
Arumugam Pillai Kala ◽  
Karachalacherevu Seetharamiah Nagaraja ◽  
Chandran Karnan

The polymeric title complex, poly[hexa-μ-aqua-diaquatetra-μ-cyanurato-tetralithium] [Li4(C3H2N3O3)4(H2O)7] n , synthesized at room temperature from an aqueous solution of lithium hydroxide and cyanuric chloride, crystallizes in the triclinic space group P\overline{1}. There are two distinct Li+ cations in the asymmetric unit, one of which, Li1, has distorted trigonal–bipyramidal geometry and is coordinated via oxygen to two cyanurate anions occupying equatorial positions, and three water molecules, two in the axial positions and the third in an equatorial position. One of the axial water ligands and the equatorial water ligand are involved in bridging to a crystallographically equivalent Li1 cation. A centre of inversion lies between the two Li1 cations and the Li1...Li1 distance is 3.037 (5) Å. The remaining axial water ligand bridges to the second Li cation, Li2, which is disordered over two crystallographic sites with approximately equal occupancy, and has an Li1...Li2 distance of 3.438 (7) Å. The terminal Li2 cation is coordinated to three water molecules and an oxygen atom from a cyanuric anion and has a distorted tetrahedral geometry. A three-dimensional network of intermolecular hydrogen bonds involving N—H...O, O—H...O and O—H...N interactions serves to hold the structure together, as confirmed by a Hirshfeld surface analysis. The title compound was further characterized using IR and UV–vis spectroscopy and TG–DTA analysis.


2014 ◽  
Vol 70 (6) ◽  
pp. m227-m228 ◽  
Author(s):  
Aymen Yangui ◽  
Walid Rekik ◽  
Slim Elleuch ◽  
Younes Abid

In the title compound, [Ni(C3H10N2)3]2[Ni(C3H10N2)2(H2O)2]Br6·2H2O, one Ni2+cation, located on an inversion centre, is coordinated by four N atoms from two ligands and by two water O atoms. The other Ni2+cation, located in a general position, is coordinated by six N atoms from three ligands. In both cases, the Ni2+cation has an octahedral coordination environment. The overall structural cohesion is ensured by three types of hydrogen bonds, N—H...Br, O—H...Br and O—H...O, which connect the two types of complex cations, the bromide counter-anions and the lattice water molecules into a three-dimensional network.


2016 ◽  
Vol 88 (2) ◽  
pp. 877-890 ◽  
Author(s):  
Agustina Yañez ◽  
Gonzalo J. Marquez ◽  
Marta A. Morbelli

The spore morphology and wall ultrastructure of Microlepia speluncae and Pteridium arachnoideum from the Paranaense Province were analyzed with LM, SEM and TEM and a comparative analysis was carried out. In both species the spores are covered by a three-dimensional network of threads branched and fused, tangentially arranged to the surface, and some free-end threads are also seen. The species were differentiated by morphology and the frequency of threads fusion and the networks distribution on the surface of the spores. In both species the exospore is two-layered in section, both layers are traversed by single or branched channels. The perispore is three-layered in section: the inner layer is adhered to the exospore, the middle layer is formed of a three-dimensional network of threads and the outer layer is discontinuous. The perispore ultrastructure of Microlepia speluncae was interpreted as formed of helical subunits displayed around a central channel. The spore morphology and perispore ultrastructure allow differentiating Microlepia from Pteridium but also to the other Dennstaedtiaceae genera that grow in the Paranaense Province. The results obtained allow establishing relationships that let us recognize different groups and gave a new reference to get a better knowledge of the family.


1979 ◽  
Vol 34 (3) ◽  
pp. 383-385 ◽  
Author(s):  
Brigitte Eisenmann ◽  
Herbert Schäfer

Abstract K2Sb4S7 · H2O crystallizes in the triclinic system with a = 1171.4(5) pm, b = 952.0(5) pm, c = 715.6(5) pm and α = 99.36(5)°, β = 86.80(5)°, γ= 103.48(5)°. One half of the Sb atoms has three sulfur neighbours forming with the free electron pair a ψ-ShS3 tetrahedron, while the other half is coordinated by four S atoms to build a ψ-trigonal SbS4 bipyramid. These polyhedra are connected by common edges and corners to a three-dimensional network with two types of channels, in which either K+ ions only or K+ ions and water molecules are located.


2009 ◽  
Vol 65 (3) ◽  
pp. m118-m120
Author(s):  
Olha Sereda ◽  
Helen Stoeckli-Evans

The title coordination polymer, [Cd3Co2(CN)12(C2H8N2)4]n, has an infinite two-dimensional network structure. The asymmetric unit is composed of two crystallographically independent CdIIatoms, one of which is located on a twofold rotation axis. There are two independent ethylenediamine (en) ligands, one of which bis-chelates to the Cd atom that sits in a general position, while the other bridges this Cd atom to that sitting on the twofold axis. The Cd atom located on the twofold rotation axis is linked to four equivalent CoIIIatomsviacyanide bridges, while the Cd atom that sits in a general position is connected to three equivalent CoIIIatomsviacyanide bridges. In this way, a series of trinuclear, tetranuclear and pentanuclear macrocycles are linked to form a two-dimensional network structure lying parallel to thebcplane. In the crystal structure, these two-dimensional networks are linkedviaN—H...N hydrogen bonds involving an en NH2H atom and a cyanide N atom, leading to the formation of a three-dimensional structure. This coordination polymer is only the second example involving a cyanometallate where the en ligand is present in both chelating and bridging coordination modes.


Author(s):  
Yongtae Kim ◽  
Sung Kwon Kang

The cation of the complex title salt, [Zn(C13H11N3)2(H2O)](NO3)2, lies about a twofold rotation axis, which passes through the ZnIIatom and the O atom of the aqua ligand. The ZnIIatom adopts a distorted trigonal–bipyramidal geometry defined by two N atoms in axial positions [angle = 166.24 (7)°], and two N and one O atom in the equatorial plane [range of angles: 115.17 (7)–122.42 (3)°]. The dihedral angle between the imidazole and aniline rings is 23.86 (5)°. In the crystal, N—H...O and O—H...O hydrogen bonds link the components into a three-dimensional network.


1994 ◽  
Vol 49 (9) ◽  
pp. 1163-1168 ◽  
Author(s):  
Harald Hillebrecht ◽  
Gerhard Thiele ◽  
Alrik Koppenhöfer ◽  
Heinrich Vahrenkamp

The title compound Zn(NH3)4(ClO4)2 crystallizes in the space group F4̄3m with a = 10.240(1) Å. The crystal structure consists of tetrahedral Zn(NH3)4 cations and two nonequivalent ClO4 anions with crystallographic Td symmetry. The complex ions constitute an arrangement which is known from the Zintl phase MgAgAs. The Zn(NH3)4 cations are ccp packed with perchlorate anions in octahedral and tetrahedral voids. Whereas the ClO4 ions centered at tetrahedral holes do not interact with the other lattice components, the perchlorate ions in the octahedral voids are connected with the ammine ligands by a hydrogen bonded three-dimensional network involving all their N, H, and O atoms. The repeating unit of this network is a N4O4(μ-H)12 cube with N-H = 1.19(2) Å and O···H = 1.98(2)Å . Raman and IR spectra were recorded between 150 and 4000 cm-1. All the expected internal modes of the complex ions could be detected and assigned. The crystallographically different ClO4 anions have nearly the same vibrational spectra, only a slight splitting of two IR modes is observed


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