On the crystal structures of some nickel hexacyanoferrates (II,III)

2004 ◽  
Vol 19 (3) ◽  
pp. 284-291 ◽  
Author(s):  
R. Martínez-Garcia ◽  
E. Reguera ◽  
J. Balmaseda ◽  
G. Ramos ◽  
H. Yee-Madeira

The crystal structures of some nickel hexacyanoferrates (II, III), including mixed compositions containing Na+, K+ and Cs+, were resolved and refined from XRD powder patterns. Data from infrared, Mössbauer and adsorption techniques provided complementary structural information. The crystal structures of Ni3[Fe(CN)6]2⋅16H2O and NiCs2[Fe(CN)6] were refined in space group Fm3m. NiNa2[Fe(CN)6]⋅2H2O and NiK2[Fe(CN)6]⋅2H2O were found to be orthorhombic (space group Pmn21). This structure (Pmn21) results from a distortion around the alkali ion, which appears as a monohydrated interstitial species. On ionic exchange in an aqueous solution containing Cs+, the orthorhombic distortion disappears and the cubic cell is obtained. Cs+ is a large cation and space is not available for interstitial water molecules. This orthorhombic model is also supported by the Mössbauer spectra of the ferrous analogs, FeK2[Fe(CN)6]⋅xH2O and Fe[Pt(CN)6]. © 2004 International Centre for Diffraction Data.

2004 ◽  
Vol 19 (3) ◽  
pp. 255-264 ◽  
Author(s):  
R. Martínez-García ◽  
E. Reguera ◽  
J. Rodriguez ◽  
J. Balmaseda ◽  
J. Roque

Mn2+and Cd2+form a family of isostructural hexacyanoferrates(II,III). Their crystal structures, including those of mixed compositions containing K+and Cs+as charge balance cations, were resolved and refined from XRD powder patterns. The crystal structures of M3[Fe(CN)6]2⋅xH2O and MCs2[Fe(CN)6] (where M=Mn, Cd) were refined in the space group Fm3m. The mixed salts, MK2[Fe(CN)6]⋅2H2O, were found to be orthorhombic (space group Pmn21). The orthorhombic structure results from a local distortion due to monohydrated potassium ions located in interstitial sites. On ionic exchange in an aqueous solution containing Cs+, the orthorhombic distortion disappears and the cubic cell is obtained. Cs+is a large ion, which practically fills the available interstitial voids stabilizing the cubic structure. In solutions of K+and Cs+the single salts, M2[Fe(CN)6]⋅8H2O (monoclinic P21/n) also transform, in this case liberating M2+ions and forming the corresponding mixed salts. An analogous but slow structural transformation was also observed in the anhydrous forms of these single salts. These structural transformations could be relevant to the use of these compounds as ion exchangers and particularly for the sorption of137Cs+from radioactive waste solutions. The XRD data were complemented with structural information from infrared (IR), Mössbauer and water vapor adsorption techniques. ©2004 International Centre for Diffraction Data.


1986 ◽  
Vol 41 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Ulrich Treiber ◽  
Michael Zwilling ◽  
Eberhard Schweda ◽  
Joachim Strähle

(NH4)3RhCl6 · H2O is obtained in form of deep red needles by slow evaporation of an aqueous solution of RhCI3 and excess NH4Cl. It crystallizes in the orthorhombic space group Pnma with lattice constants a = 1219.3. b = 700.7, c = 1416.7 and Z = 4. The structure is built up by octahedral RhCl63- anions and NH4+ cations. The water molecules form hydrogen bridges with NH4+ cations. The reaction of (NH4)3RhCl6 with Ag+ yields Ag2[RhCl5(H2O)] and AgCl.


1996 ◽  
Vol 51 (10) ◽  
pp. 1469-1472 ◽  
Author(s):  
Joachim Pickardt ◽  
Britta Kühn

Crystals of |Zn(cnge)2(SCN)2]-2H2O (1) were obtained by evaporation of an aqueous solution of Z n(SO4)·7H2O , KSCN, and cyanoguanidine. Crystals of Zn(eoge)Br2 (2) were obtained by reaction of ZnBr2 and cyanoguanidine in ethanol/water. Both compounds are monoclinic, space group C2/c, 1: Z = 4, a = 1919.6(7), b = 467.3(2), c = 1838.5(6) pm, β = 112.99(3)°, 2: Z = 8, a = 1799.5(6), b = 878.7(2), c = 1367.2(5) pm, β = 101.52(3)°. In 1 each Zn is bonded to two cyanoguanidine molecules and via the N atoms to two NCS groups. Intermolecular hydrogen bonds lead to chains along the a-axis, and these chains are again connected via hydrogen bonds to the two crystal water molecules. In the course of the formation of 2, the cyanoguanidine reacted with the ethanol to form 1-ethoxyiminomethylguanidine. This ligand forms chelate rings with the Zn atoms, which are tetrahedrally coordinated by the two imino N atoms of the ligand and by two bromine atoms.


2004 ◽  
Vol 59 (2) ◽  
pp. 228-232 ◽  
Author(s):  
Ayhan Elmali ◽  
Celal T Zeyrek ◽  
Yalcin Elerman

[N,N′’-Bis(3-methoxysalicylidene)-1,3-diaminopropane]nickel(II) dihydrate [Ni(C19H20N2O4)· 2(H2O)] 1 and [N,N′-bis(3-methoxysalicylidene)-1,4-diaminobutane]copper(II) [Cu(C20H22N2O4)] 2 have been synthesized and their crystal structures determined. Crystals of compound 1 are orthorhombic, space group Pnma, a = 7.509(3), b = 22.070(7), c = 11.532(4) Å, V = 1611.1(12) Å3, Z = 4 and Dc = 1.498 g·cm−3. The molecule 1 has mirror symmetry, but the ligand is not planar. The two parts of the Schiff base moieties are folded so as to form an angle of 21.6(1)°. The Ni atom is in a distorted octahedral geometry and coordinated by the donor atoms of the ligand in the horizontal plane and of two water molecules. Crystals of compound 2 are monoclinic, space group P21/c, a = 9.488(1), b = 21.918(3), c = 8.413(1) Å, β = 91.45(1)°, V = 1749.0(4) Å3, Z = 4 and Dc = 1.587 g·cm−3. The Cu atom is coordinated by an N2O2 donor set from the imine-phenol ligand in a distorted planar geometry, with the two phenolate O atoms deprotonated. The Cu-O bond lengths are 1.854(3) and 1.868(3)Å . The Cu-N bond lengths are 1.931(3) and 1.950(3) Å, the dihedral angle between the two 3-methoxysalicylidene groups is 43.4(1)°.


1997 ◽  
Vol 52 (9) ◽  
pp. 1094-1102 ◽  
Author(s):  
Michael Feist ◽  
Sergej Trojanov ◽  
Anja Stiewe ◽  
Erhard Kemnitz ◽  
Ralf Kunze

The compounds (trienH2)[Mn(H2O)3X3]X · H2O(X = Cl,Br) crystallize at room temperature from equimolar solutions of triethylenediamine and MnX2 · 4 H2O in 3M HX in the orthorhombic space group P212121 with a =6.828( 1), b = 12.128(2), c = 18.367(4) Å, Z = 4 for the chloride, and a = 7.001 (1), b = 12.651 (3), c = 18.885(4) Å, Z = 4 for the bromide, respectively. Both structures contain cations (trienH2)2+, complex octahedral anions [Mn(H2O)3X3]- , isolated halide ions and water molecules. The thermal behavior has been investigated on the basis of conventional thermoanalytical as well as TG-MS techniques. The thermal decomposition proceeeds in three stages, i.e. the dehydration forming (trienH2)[MnX4], a phase transition of the tetrahalomanganates(II), and, finally, their decomposition which is influenced by the nature of the atmosphere. The dehydration step is reversible.


1990 ◽  
Vol 68 (8) ◽  
pp. 1277-1282 ◽  
Author(s):  
Ivor Wharf ◽  
Michel G. Simard ◽  
Henry Lamparski

Tetrakis(p-methylsulphonylphenyl)tin(IV) and tetrakis(p-methylsulphinylphenyl)tin(IV) n-hydrate have been prepared and their spectra (ir 1350–400 cm−1; nmr, 1H, 13C, 119Sn) and X-ray crystal structures are reported. The first compound is monoclinic, space group C2/c, Z = 4, with a = 21.589(6), b = 6.207(3), c = 22.861(11) Å, β = 93.80(3)° (22 °C); the structure was solved by the direct method and refined by full-matrix least squares calculations to R = 0.043 for 2755 observed reflections. It has 2 molecular symmetry with the methyl group and one oxygen atom completely disordered in both CH3S(O2) groups in the asymmetric unit. The second compound is tetragonal, space group P42/n, Z = 2, with a = b = 15.408(6), c = 6.379(2) Å (−100 °C); the structure was solved by the Patterson method and refined by full-matrix least squares calculations to R = 0.060 for 1209 observed reflections. It has [Formula: see text] molecular symmetry with the whole asymmetric unit disordered. Water molecules occupy positions on parallel 42 axes but molecular packing requirements prevent all sites having 100% occupancy giving n ~ 1 for the hydrate. Keywords: Tetra-aryltins, crystal structures, sulphone, sulphoxide, hydrogen-bonding.


1995 ◽  
Vol 50 (5) ◽  
pp. 828-832 ◽  
Author(s):  
Joachim Pickardt ◽  
Isabella Hoffmeister

Abstract Crystals of both complexes were obtained by evaporation of the ethanol solvent. The crystals of [{CuCl(C10N4H24)}2][CdCl4] are tetragonal, space group I4̄2d, Z = 4, a = b = 1784.1(11), c = 1101.1(8) pm. Each copper atom is bonded to one cyclam ligand and two chlorine atoms which are acting as bridging ligands and connect the copper atoms to chains of distorted octahedra. Distorted tetrahedra of CdCl4 are situated in cavities between these chains. The crystals of [Cu(C10N4H24)][CdCl3(H2O)2]Cl are monoclinic (b), space group C2/c, Z = 4, a = 1581.9(8), b = 1323.3(7), c = 924.0(5) pm, β = 94.31(5)°. Cadmium is coordinated to four chlorine atoms and two water molecules, while all of the chlorine atoms act as bridging ligands connecting every cadmium atom to two adjacent cadmium atoms and to two copper atoms which lie in plane with the N atoms.


2004 ◽  
Vol 60 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Biserka Kojić-Prodić ◽  
Berislav Perić ◽  
Zoran Štefanić ◽  
Anton Meden ◽  
Janja Makarević ◽  
...  

To compare the structural properties of oxalamide and thiooxalamide groups in the formation of hydrogen bonds suitable for supramolecular assemblies a series of retropeptides was studied. Some of them, having oxalamide bridges, are gelators of organic solvents and water. However, retropeptides with oxygen replaced by the sp 2 sulfur have not exhibited such properties. The crystal structures of the two title compounds are homostructural, i.e. they have similar packing arrangements. The monothio compound crystallizes in the orthorhombic space group P212121 with two molecules in the asymmetric unit arranged in a hydrogen-bond network with an approximate 41 axis along the crystallographic b axis. However, the dithio and dioxo analogues crystallize in the tetragonal space group P41 with similar packing patterns and hydrogen-bonding systems arranged in agreement with a crystallographic 41 axis. Thus, these two analogues are isostructural having closely related hydrogen-bonding patterns in spite of the different size and polarity of oxygen and sulfur which serve as the proton acceptors.


1996 ◽  
Vol 49 (12) ◽  
pp. 1301 ◽  
Author(s):  
GW Allen ◽  
ECH Ling ◽  
LV Krippner ◽  
TW Hambley

The preparation and purification of [Pt( hpip )Cl2] and [Pd( hpip )Cl2] ( hpip = homopiperazine = 1,4-diazacycloheptane) are described. Crystal structures of [Pt( hpip )Cl2] and [Pd( hpip )Cl2] have been determined by X-ray diffraction methods and refined to R values of 0.023 (932 F) and 0.023 (948 F). The crystals of [Pt( hpip )Cl2] are orthorhombic, space group Pbcm , a 7.7019(8), b 9.8080(12), c 12.1944(14) Ǻ, and those of [Pd( hpip )Cl2] are monoclinic, space group P21/m, a 6.1001(9), b 11.527(2), c 6.458(I) Ǻ, β 106.30(2)°. The seven- membered rings of the ligands in both complexes adopt boat-like conformations in which the five- membered chelate ring has an eclipsed N-C-C-N group and the six- membered chelate ring adopts a chair conformation. Molecular mechanics methods were used to investigate whether this conformation was a crystallographic artefact but it was found to be real. An alternative conformation in which the six-membered chelate ring adopts a skew-boat conformation was also investigated. It was found to be less stable than the conformation observed in the crystal structures, but to a degree that depends on whether non-bonded interactions involving the metal atom were included or not.


1994 ◽  
Vol 49 (6) ◽  
pp. 770-772 ◽  
Author(s):  
Klaus Schulbert ◽  
Rainer Mattes

The reactions of N-substituted dithiocarbamic acid esters and nickel acetate yield, by partial degradation of the esters, the polynuclear nickel thiolato complexes cyclo-[(μ-SMe)2Ni]6, 1 and [(μ-SMe)2(Ni(MeNHCS2))2, 2. Their crystal structures have been determined. The Ni coordination spheres are comprised of four sulfur atoms in a planar arrangement. 1 is a second, highly symmetrical modification of the already known cyclic hexamer Ni6(SMe)12. In 2 two Ni(PhNHCS2) moieties are bridged to dimers by thiolato groups. Two of these dimers are connected to a tetramer by weak axial Ni-S interactions. Crystal data for 1: monoclinic, space group P21/n, a = 986.1(2), b = 1308.1(3), c = 1228.6(2) pm, β = 96.07(3)°, Z = 2, R = 0.072, Rw = 0.062, 3797 reflections. 2: orthorhombic, space group Pnma, a = 1790.0(4), b = 1806.7(4), c = 934.4(2) pm. Z = 4, R = 0.061, Rw = 0.051, 2079 reflections


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