A Novel Coordination Structure of Dichromates Bonding to Copper (II): [Cu(bipy)2(Cr2O7)] · 2 H2O

Dark-green multimetal compound crystal [Cu(bipy)₂(Cr₂O₇)]· 2 H₂O was obtained from aqueous solution of Cu(NO₃)₂, K₂Cr₂O₇ and bipyridine. The crystal structure was determined by X-ray crystallography: triclinic P1 , a = 7.716(3) Å, b = 9.656(3) Å, c = 15.517(5)Å, α = 77.41(3)°, β = 81.04(3)°, γ = 82.33(3)°, Z = 2. In this compound, two chromium atoms and a copper atom are linked by two oxo bridges (Cu(II) O Cr(VI) O Cr(VI)). The copper coordination polyhedron corresponds to a five-coordinated distorted trigonal bipyramid.     

Structure and morphology of [icosahedral Al62Cu25.5Fe12.5]100−x[decagonal Al70Co15Ni15]x alloys, for x=10(03 and 510)

Alloys made from mixtures of Al₆₂Cu_25.5Fe_12.5 icosahedral quasicrystal (IQC) and Al₇₀Co₁₅Ni₁₅ decagonal quasicrystal (DQC) were studied by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The transition from IQC to DQC was thus discussed by studying the evolution of their constituent phases in each alloy. Three approximant phases were found as common phases in most of the pseudo-binary alloys: λ-Al₁₃Fe₄, β-AlFe and τ3-Al₃Ni₂. It is found that, with the increment of the DQC content in the alloy, the λ phase changes from Al₁₃Fe₄ to Al₁₃Co₄ and the τ3 phase changes from Al₃Cu₂ to Al₃Ni₂. The formation of these phases were found also to follow the evolution of their corresponding e/a-constant lines in the Al–(Cu,Ni)–(Fe,Co) pseudo-ternary phase diagram. Under this framework, the roles played by the related approximants in the transition process are briefly discussed.     

X‐ray powder diffraction study of the semiconducting alloy Cu2Cd0.5Mn0.5GeSe4

The structure of the semiconducting alloy Cu₂Cd_0.5Mn_0.5GeSe₄ was refined from an X‐ray powder diffraction pattern using the Rietveld method. The present alloy crystallizes in the wurtz‐stannite structure, space group Pmn2₁ (N^o 31), and unit cell parameters values of a = 8.0253(2) Å, b = 6.8591(2) Å, c = 6.5734(2) Å and V = 361.84(2) ų. The structure exhibits a three‐dimensional arrangement of slightly distorted CuSe₄, Cd(Mn)Se₄ and GeSe₄ tetrahedras connected by corners. © 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim     

Synthesis and Structure Study of the Complex [Cu2 (μ–C2O4) (C10H8N2)2(H2O)2] (C6H4COSO2N)2 Crystal Structure Containing Cu (II) Bipy Oxalato and Saccharin

The title compound has been synthesized and its crystal structure determined at room temperature. MW = 927.86, monoclinic, space group P2₁/c, Z = 2, a = 9.283(1) Å, b = 16.239(2) Å, c = 12.209(1) Å, β = 99.848(9)°. The crystal structure consists of repeated [Cu₂(μ–C₂O₄)(C₁₀H₈N₂)₂ · (H₂O)₂]₂ cations and non-coordinated saccharin anions. Each copper ion is in a square pyrimidal environment with two oxalate oxygen and two bipyridine nitrogen atoms as a base and one water molecule at the apex. The two copper ions are bridged by oxalato and the distance is 5.138 Å.     

Synthesis and crystal structure of novel complex phosphate Li5Cu2Al(PO4)4

A new complex phosphate Li₅Cu₂Al(PO₄)₄ has been obtained by the flux method in the Cs-Li-Cu-V-P-O system. Its crystal structure has been determined by X-ray diffraction (R ₁ = 2.74%) to be as follows: sp. gr. $P\bar 1$ , a = 4.860(5) Å, b = 7.788(5) Å, c = 8.324(5) Å, α = 69.542(5)°, β = 90.016(5)°, γ = 75.318(5)°, Z = 1, and V = 284.2(4) ų. The compound under study has a dense structure and a three-dimensional framework build up of [LiO₅], [AlO₆], [Cu/LiO₅], and [CuO₄] polyhedra and [PO₄] tetrahedra. A comparative crystal-chemical analysis of two isotypic compounds with a general formula Li₅Cu₂ M(PO₄)₄ (M = Fe, Al) has been performed. Topological relations between the Na₂Mg₅(PO₄)₄ and Li₅Cu₂ M(PO₄)₄ crystal structures, which are characterized by different cationic compositions, are revealed.     

Specific features of cation distribution in the crystal structure of mariinskite BeCr2O4 (Derivative of olivine-type structure)

Two samples of mineral mariinskite have been investigated by single-crystal X-ray diffraction, and their formulas were established to be Cr_1.43Al_0.64Be_0.9O₄ (sample 1) and Cr_1.32Al_0.74Be_0.9O₄ (sample 2). The parameters of their orthorhombic cells are, respectively, a = 4.487(1) Å, b = 5.629(1) Å, and c = 9.732(2) Å and a = 4.478(1) Å, b = 5.620(1) Å, and c = 9.746(2) Å; sp. gr. P2₁2₁2₁. The structures of samples 1 and 2 were solved by direct methods and refined in the anisotropic approximation of thermal atomic vibrations to R = 8.9 and 6.06%, respectively. Two components coexist in the mineral crystal structure, which belong to olivine-type structure and are interrelated through reflection in the mirror symmetry plane passing through close-packed layers. The presence of additional octahedral sites (which are statistically occupied by Cr³⁺ ions in the same way as vacancies in principal sites (occupancy ～80%)) in the mariinskite structure lowers the mineral symmetry from the centrosymmetric sp. gr. Pcmn, characteristic of olivine-group minerals, to the acentric sp. gr. P2₁2₁2₁.     

Hydrothermal Synthesis and Morphology of Thomsonite and Edingtonite

The hydrothermal treatment of different glasses of the composition 2 Na₂O–8 CaO–10 Al₂O₃– 20 SiO₂ and 2 BaO–2 Al₂O₃–6 SiO₂ at one kilobar pressure in a temperature-range between 80 °C and 230 °C lead to the formation of the zeolite-minerals thomsonite (orthorhombic symmetry space-group Pbmn, a = 13.05 Å, b = 13.09 Å and c = 13.22 Å), and edingtonite (orthorhombic symmetry, space-group: P2,2,2, a = 9.55 Å, b = 9.67 Å and c = 6.52 Å). Under the chosen hydrothermal conditions both mineral phases are formed in the whole temperature interval.     

Synthesis and characterization of single crystals of the layered copper hydroxide acetate Cu2(OH)3(CH3COO)·H2O

Single‐crystals of the layered copper hydroxide acetate Cu₂(OH)₃(CH₃COO)·H₂O were synthesized by heating copper acetate solution at 60 °C. The standard synthesis of the title compound based on slow titration of copper acetate solution with NaOH yielded materials with worse morphology and an additional phase present. The obtained products were characterized with powder X‐ray diffraction, high temperature powder X‐ray diffraction, scanning electron microscopy and infrared spectroscopy. The crystal structure was determined from single‐crystal X‐ray diffraction data, collected both at 120 K and at 293 K. The title compound crystallizes in the monoclinic botallackite‐type layered structure, space group P 2₁, with the lattice parameters a = 5.5776(3) Å, b = 6.0733(2) Å, c = 18.5134(8) Å, β = 91.802(4)° and a = 5.5875(4)Å, b = 6.0987(4) Å, c = 18.6801(10)Å, β = 91.934(5)° for 120 K and for 293 K, respectively. Acetate groups and water molecules are interlayered between corrugated sheets of edge‐sharing CuO6 octahedra exhibiting strong distortion resulted from the Jahn‐Teller effect. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Syntheses and crystal structures of two polymorphs of three‐dimensional silver (I) 5‐(3‐aminophenyl)tetrazolates

Two polymorphs of silver 5‐(3‐aminophenyl)tetrazolates – α‐ and β‐Ag(amphttz) have been obtained by the reaction of amphttzH with AgNO₃ in presence of ammonia either in ambient condition or under the hydrothermal condition, respectively (amphttzH = 5‐(3‐aminophenyl)tetrazole). Both of the two phases of Ag(amphttz) were characterized by elemental analyses, IR spectra and single‐crystal X‐ray diffraction. X‐ray analysis shows α‐, β‐phases crystallize in P ‐1 with a = 8.551 (2) Å, b = 8.720(2) Å, c = 11.173(2) Å, α = 98.15(3)°, β = 90.95(3)°, γ = 95.45(3)° and C 2/c with a = 13.542(3) Å, b = 10.135(2) Å, c = 12.610(3) Å, β = 113.58(3)°, respectively. The two polymorphs exhibit different 3D structures. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Formation of a new F.C.C. τ2 phase in rapidly quenched Al55Cu35V10 alloy

X‐ray diffraction and transmission electron microscopy experiments were carried out to study the structure of rapidly solidified as‐cast and annealed Al₅₅Cu₃₅V₁₀ alloy. The as‐cast Al₅₅Cu₃₅V₁₀ alloy shows the presence of a new f.c.c. τ2 phase (a=0.58nm) along with a b.c.c. (a = 0.89 nm) phase which after subsequent annealing transforms into single f.c.c. phase (a = 0.58 nm). In this paper, it is also reported that these phases are crystalline approximants to an icosahedral phase on the basis of e/a (valence electron per atom) constant line. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Structure changes in Al80Ni15Y5 amorphous alloy

The structure of Al₈₀Ni₁₅Y₅ amorphous alloy at various temperatures have been studied with X-ray diffraction methods. The obtained scattered intensities, structure factors, pair correlation functions and main structure parameters have been analyzed. Temperature dependences of the parameters suggest formation of Al, Al₃Ni and Al₂₃Ni₆Y₄ phases upon crystallization of an amorphous alloy.     

Structural characterization and magnetic properties of the spinel compound CoIn0.5Cr1.5S4

Single crystals of the magnetic semiconductor CoIn_0.5Cr_1.5S₄, belong to the system CoIn_(2‐2X)Cr_(2X)S₄ with x = 0.75, was grown by the chemical transport method. X‐ray powder diffraction characterization by the Rietveld method indicated that CoIn_0.5Cr_1.5S₄ crystallizes in the space group Fd‐3m, Z = 8, with a = 10.0700(6) Å and V = 1021.2(1) ų, in a normal spinel structure. The temperature dependence of the DC magnetization suggests that the studied compound presents a ferromagnetic behavior with a Curie temperature Tc = 220 K. Sharp spin‐glass like behavior was found also. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Study on crystallization kinetics of Al65Cu20Ti15 amorphous alloy

The crystallization behavior and thermal stability of amorphous phases of Al₆₅Cu₂₀Ti₁₅ alloy obtained by mechanical alloying were investigated by using in-situ X-ray diffraction and differential scanning calorimetry (DSC) under non isothermal and isothermal conditions. The result of a Kissinger analysis shows that the activation energy for crystallization is 1131 kJ/mol. The higher stability against crystallization of Al₆₅Cu₂₀Ti₁₅ amorphous alloy is attributed to the stronger interaction of atoms in the Al-Cu-Ti system and formed of complicated compound like Al₅CuTi₂ and Al₄Cu₉ as primary phases. The isothermal crystallization was modeled by using the Johnson-Mehl-Avrami (JMA) equation. The Avarami exponents suggest that the isothermal crystallization is governed by a three-dimensional diffusion-controlled growth.     

Synthesis and X-ray structure studies of complex [Cu(o-phenanthroline)2 (saccharin)] · (saccharin) · 2 H2O

The title compound has been synthesized and its crystal structure determined at room temperature, M_r = 824.34, triclinic, space group P–1(2), a = 13.622(4), b = 13.770(4), c = 11.167(3) Å; α = 104.83(2), β = 110.01(2), γ = 62.04(2) degree; U = 1727.0(9) ų, Z = 2, D_calc = 1.59 g/cm³. The final R is 0.066 for 3299 independent observed reflections with I ≧ 3σ(I). The crystal structure consists of repeated [Cu(o-phen)₂(sac)]⁺ cations, non-coordinated saccharin anion and two lattice water. And the central ion Cu²⁺ forms a trigonal-bipyramidal stereochemistry.     

Crystal structure analysis and refinement of Kalabsha kaolinite (Al2Si2O5(OH)4)

The crystal structure of the kaolinite mineral from Kalabsha, Aswan, Egypt, has been investigated with a two-step procedure of the X-ray powder pattern-fitting. The unit cell is found to be triclinic, P1, a = 5.1577(15), b = 8.9417(23), c = 7.3967(40) Å, α = 91.672(5)°, β = 104.860(2) and γ = 89.898(2)°. The refinements of the non-hydrogen atomic positions showed a reliability factors R_WB = 0.037 and R_B = 0.0417. The average rotation angle in the tetrahedral layer in 10°.     

The Crystal and Molecular Structure of the Complex Diaquatetrakis(imidazole)copper(II) Terephthalate Crystal Structure Containing Cu(II) Him and TA

The title compound has been synthesized and its crystals structure determined at room temperature. MW = 536.01, monoclinic, space group C2/c, Z = 4, a = 22.193(5) Å, b = 8.038(2) Å, c = 15.699(4) Å, β = 119.64(2)°. The crystal structure consists of repeated [Cu(Him)₄(H₂O)₂] (Him = imidazole) cations and non-coordinated terephthalato dianions. The copper(II) ion displays an elongated octahedral coordination being linked to the four nitrogen atoms of the four imidazole ligands and to the two oxygen atoms of the two water molecules. The terephthalato dianions are hydrogen bonded to the four water molecules and four imidazole groups.     

Crystal structures of mixed compounds Cu(2)Gly(D-Ser)(L-Ser)2 and Cu(2)Gly 3(L-Ser)

-The crystal structures of mixed coordination compounds, Cu(2)Gly(D-Ser)(L-Ser)₂(I) and Cu(2)Gly ₃(L-Ser)(II), which contain the amino acid residues of glycine (Gly) and serine (Ser) in the 1: 3 and 3: 1 ratio, respectively, are studied by electron diffraction. Crystals I and II are triclinic, Z = 1, and space group P1. For I, a = 8.96(2) Å, b = 9.66(2) Å, c = 5.07(2) Å, α = β = 90°, and γ = 92.8(3)°. For II, a = 8.37(2) Å, b = 9.65(2) Å, c = 5.06(2) Å, α = β = 90°, and γ = 92.8(3)°. Compounds I and II have layered structures that are based on the CuGly(L-Ser) fragment. Structures I and II differ mainly in their interlayer spacing and configuration of the interlayer space.     

Crystal and molecular structure of di(perchlorato)(1,4,8,11-tetraazacyclotetradecane)copper (II). Cu(cyclam) (ClO4)2

The title compound, Cu(C₁₀H₂₄N₄)(ClO₄)₂, crystallizes in the triclinic system with unit cell dimensionsa= 8.744,b= 8.022,c= 8.677 Å, α = 118.7, β = 56.9, γ = 113.5 °,Z= 1, space group P¯1. The structure was solved by Fourier methods and refined by least-squares techniques using the 1545 nonzero three-dimensional counter-diffraction intensity data (CuKα) to give a conventionalR factor of 0.056. The coordination sphere of the copper ion is defined by a planar arrangement of the four nitrogen donors in the macrocyclic ligand with oxygen atoms from the perchlorate groups lying above and below this plane. The resulting tetragonally distorted octahedron of donor atoms gives interatomic distances Cu?N = 2.02(4) Å and 2.02(3) Å, and Cu?N = 2.57(4) Å.     

Neutron and X-ray diffraction study of superstructure and localized magnetic moments in Cu0.5Fe0.5Cr2S4 and Cu0.5In0.5Cr2S4 compounds

The superstructure parameters for the Cu_0.5Fe_0.5Cr₂S₄ and Cu_0.5In_0.5Cr₂S₄ compounds have been determined by neutron and X-ray diffraction. The localized magnetic moments in different sublattices measured for Cu_0.5Fe_0.5Cr₂S₄ are equal to 3.06 ± 0.17 μB for Fe³⁺ ions in the A-site and 2.76 ± 0.22 μB for Cr³⁺ ions in the B-site (Cu⁺ possess no magnetic moment), which are much less than the magnetic moments for the ions in the purely ionic state.     

Crystal structure refinement of the ternary compound Cu2SnTe3 by X‐ray powder diffraction

The ternary compound Cu₂SnTe₃ crystallizes in the Imm2 (Nº 44) space group, Z = 2, with a = 12.833(4) Å, b = 4.274(1) Å, c = 6.043(1) Å, V = 331.5(1) ų. Its structure was refined from X‐ray powder diffraction data using the Rietveld method. The refinement of 25 instrumental and structural variables led to R_p = 10.2%, R_wp = 11.8%, R_exp = 7.7%, R_B = 10.6%, S = 1.6 and χ² = 2.6, for 5501 step intensities and 163 independent reflections. This compound is isostructural with Cu₂GeSe₃, and consists of a three‐dimensional arrangement of slightly distorted CuTe₄ and SnTe₄ tetrahedra connected by common corners. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)