The structure of reyerite, (Na,K)2Ca14Si22Al2O58(OH)8.6H2O

1988 ◽  
Vol 52 (365) ◽  
pp. 247-255 ◽  
Author(s):  
Stefano Merlino

AbstractThe crystal structure of reyerite, (Na,K)2Ca14Si22Al2O58(OH)8.6H2O, Z = 1, was refined in the space group P, a = 9.765, c = 19.067Å, to R = 0.064 for 1540 reflections. The structure is composed of the following structural units: (a) tetrahedral sheets S1, with composition (Si8O20)8−, characterized by six-membered rings of tetrahedra; (b) tetrahedral sheets S2, characterized by six-membered rings of tetrahedra, with six tetrahedra pointing in one direction and two pointing in the other direction—the apical oxygens of these two tetrahedra connect two inversion-related S2 sheets to build double sheets, with composition (Si14Al2O38)14− and ordered distribution of aluminum cations; (c) sheets O of edge-sharing calcium octahedra. The various structural units are connected through corner sharing according to the schematic sequence ……; the corresponding composition is [Ca14Si22Al2O58(OH)8]2−. The charge balance is restored by alkali cations which are placed, together with water molecules, in the cavities of the structure at the level of the double tetrahedral sheet.

2001 ◽  
Vol 56 (3) ◽  
pp. 271-280 ◽  
Author(s):  
Ingo Pantenburg ◽  
Karl-Friedrich Tebbe

Abstract [Rb(benzo-18-crown-6)](I5) H2O could be prepared by the reaction of benzo-18-crown-6, rubidium iodide, and iodine in ethanol / dichloromethane. It crystallizes in the monoclinic space group P21/a with a = 1881.8(3), b = 1439.0(2), c = 2269.0(3) pm, ß = 111.24(1)° and Z = 8. The crystal structure was refined to RF = 0.038 for 5310 reflections. It contains two independent molecules. The two cations and the coordinating water molecules form a zigzag chain running along [100] paralleled by two structurally similar pentaiodide chains with one leg of the V-shaped pentaiodide ion forming the backbone of the chain. In both cases the other leg stands out in a novel fashion without forming a coplanar cis or trans configuration known from other pentaiodides. Anionic motifs of other crystalline pentaiodides are summarized and discussed.


1985 ◽  
Vol 38 (3) ◽  
pp. 413 ◽  
Author(s):  
Maureen F Mackay ◽  
James D Morrison ◽  
Jacqueline M Gulbis

Triclinic crystals of colchiceine hemihydrate, C21H23N06.!H20, belong to the space group PI with a 8 .211(1), b 8�361(1), c16 �898(2) A, a 92 �35(1)", J3 93 �93(1)", l' 121�35(1)" and Z 2. The structure was solved by direct methods and successive difference syntheses with diffractometer data measured with CuKa radiation. Refinement converged at R 0�053 for 2798 observed reflections. The two tautomers, one of the isoco1chiceine and the other of the colchiceine form, exist as independent entities in the crystal; the angles between the normals to the plane of the benzene and troponoid rings are 44�5(4)" and 51� 5(5)" respectively. The hydroxyl and N-acetyl groups are oriented to form channels along the a-axis which accommodate the water molecules.


1979 ◽  
Vol 32 (2) ◽  
pp. 301 ◽  
Author(s):  
V Diakiw ◽  
TW Hambley ◽  
DL Kepert ◽  
CL Raston ◽  
AH White

The crystal structure of the title compound, Ca(C6H2N307)2,5H2O, has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.049 for 1513 'observed' reflections. Crystals are orthorhombic, Pmab, a 24.169(6), b l0.292(7), c 8.554(2) �, Z 4. The stereochemistry about the calcium has not been observed previously for the system [M(bidentate)2- (unidentate)4]; in the present structure, the calcium is coordinated by a pair of bidentate picrate ligands and the four water molecules in an array in which three of the water molecules occupy a triangular face of a square antiprism, the overall array having m symmetry. The remaining water molecule occupies a lattice site with no close interaction with the other species.


2012 ◽  
Vol 68 (9) ◽  
pp. m265-m268 ◽  
Author(s):  
Kai-Long Zhong ◽  
Ming-Yi Qian

The title compound, {[Co(H2O)6][Co(SO4)(C10H8N2)(H2O)3][Co(SO4)2(C10H8N2)(H2O)2]}n, contains three crystallographically unique CoIIcentres, all of which are in six-coordinated environments. One CoIIcentre is coordinated by two bridging 4,4′-bipyridine (4,4′-bipy) ligands, one sulfate ion and three aqua ligands. The second CoIIcentre is surrounded by two N atoms of two 4,4′-bipy ligands and four O atoms,i.e.two O atoms from two monodentate sulfate ions and two from water molecules. The third CoIIcentre forms part of a hexaaquacobalt(II) ion. In the crystal structure, there are two different one-dimensional chains, one being anionic and the other neutral, and adjacent chains are arranged in a cross-like fashion around the mid-point of the 4,4′-bipy ligands. The structure features O—H...O hydrogen-bonding interactions between sulfate anions and water molecules, resulting in a three-dimensional supramolecular network.


1994 ◽  
Vol 49 (10) ◽  
pp. 1444-1447 ◽  
Author(s):  
Helmut Goesmann ◽  
Dieter Fenske

AbstractSingle crystals of the title compound have been prepared by the reaction of benzonitrile with LiN-(SiMe3)2 in hexane and subsequent evaporation of the solvent. Space group P21/n, Z = 4, structure solution with 7945 observed unique reflections. R = 0.052. Lattice dimensions at -70 °C: a = 1485.2(9); b = 2486.9(11); c = 1568.9(8) pm; β = 91.06(4)°. The compound forms a trimeric ion ensemble in which two of the lithium cations are coordinated by three nitrogen atoms of two phenylamidinate an ions, the other one by four nitrogen atoms of two chelating phenylaminidate anions and in addition by the nitrogen atom of a benzonitrile molecule.


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.


2018 ◽  
Vol 82 (6) ◽  
pp. 1355-1367 ◽  
Author(s):  
Owen P. Missen ◽  
Stuart J. Mills ◽  
John Spratt ◽  
Mark D. Welch ◽  
William D. Birch ◽  
...  

ABSTRACTThe crystal structure of eztlite has been determined using single-crystal synchrotron X-ray diffraction and supported using electron microprobe analysis and powder diffraction. Eztlite, a secondary tellurium mineral from the Moctezuma mine, Mexico, is monoclinic, space group Cm, with a = 11.466(2) Å, b = 19.775(4) Å, c = 10.497(2) Å, β = 102.62(3)° and V = 2322.6(9) Å3. The chemical formula of eztlite has been revised to ${\rm Pb}_{\rm 2}^{2 +} {\rm Fe}_3^{3 +} $(Te4+O3)3(SO4)O2Cl from that stated previously as ${\rm Fe}_6^{3 +} {\rm Pb}_{\rm 2}^{2 +} $(Te4+O3)3(Te6+O6)(OH)10·nH2O. This change has been accepted by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, Proposal 18-A. Eztlite was reported originally to be a mixed-valence Te oxysalt; however the crystal structure, bond-valence analysis and charge balance considerations clearly show that all Te is tetravalent. Eztlite contains a unique combination of elements and is only the second Te oxysalt to contain both sulfate and chloride. The crystal structure of eztlite contains mitridatite-like layers, with a repeating triangular nonameric [${\rm Fe}_9^{3 +} $O36]45– arrangement formed by nine edge-sharing Fe3+O6 octahedra, decorated by four trigonal pyramidal Te4+O3 groups, compared to PO4 or AsO4 tetrahedra in mitridatite-type minerals. In eztlite, all four tellurite groups associated with one nonamer are orientated with the lone pair of the Te atoms pointing in the same direction, whereas in mitridatite the central tetrahedron is orientated in the opposite direction to the others. In mitridatite-type structures, interlayer connections are formed exclusively via Ca2+ and water molecules, whereas the eztlite interlayer contains Pb2+, sulfate tetrahedra and Cl–. Interlayer connectivity in eztlite is achieved primarily by connections via the long bonds of Pbφ8 and Pbφ9 groups to sulfate tetrahedra and to Cl–. Secondary connectivity is via Te–O and Te–Cl bonds.


1988 ◽  
Vol 43 (10) ◽  
pp. 1279-1284 ◽  
Author(s):  
Mervat El Essawi ◽  
H Gosmann ◽  
D Fenske ◽  
F Schmock ◽  
K Dehnicke

Triphenylmethylphosphonium nitrite and formate have been prepared by the reaction of [PPh3Me]I with silver nitrite, and lead formate, respectively, in aqueous solutions. [PPh3Me]NO2 (1) forms pale yellow crystals, and [PPh3Me]HCO2·H2O (2) forms white crystals. Both compounds are soluble in water, ethanol, and dichloromethane. In moist air 2 is hydrated to yield [PPh3Me]HCO2·2H2O (3). The compounds were characterized by their IR spectra, 1 and 2 also by X-ray crystal structure determinations.[PPh3Me]NO2 (1): space group P21/n, Z = 4, 2088 independent observed reflexions, R = 0.062. Lattice dimensions (20 °C): a = 914.7(3), b = 1887.5(9), c = 1080.0(4) pm, β = 110.29(3)°. The compound consists of PPh3Me+ ions and NO2- anions with bond lengths of 114.2(6) pm and a bond angle of 124.1(7)°. [PPh3Me]HCO2·H2O (2): space group P21/n, Z = 4, 2973 independent observed reflexions, R = 0.069. Lattice dimensions (-20 °C): a = 931(2), b = 1558(3), c = 1281(2) pm, β = 105.9(1)°. The compound consists of PPh3Me+ ions and formate anions which form centrosymmetric dimeric units [HCO2·H2O]22- through hydrogen bridges of the water molecules. Bond lengths CO 122.4(4) and 120.9(4) pm. bond angle OCO 129.9(4)°.


2008 ◽  
Vol 27 (1) ◽  
pp. 1
Author(s):  
Gligor Jovanovski ◽  
Petre Makreski ◽  
Bojan Šoptrajanov

Infrared and Raman vibrational spectra of magnesium disaccharinate heptahydrate, Mg(sac)2⋅7H2O, in the 4000–380 cm–1 region (for infrared) and 4000–100 cm–1 region (for Raman) were studied. The assignment of the spectra was based on the experimental data for the previously studied metal saccharinates as well as the literature data for the ab initio calculations on the free deprotonated saccharinato species. Special attention was paid to the analysis of the H2O, CO and SO2 stretching modes. The spectral picture in the regions of the water, carbonyl and sulfonyl stretches is correlated with the number of the crystallographically determined non-equivalent H2O, CO and SO2 structural units. It was found that the presence of seven crystallographically different water molecules in the structure (fourteen different Ow⋅⋅⋅O and Ow⋅⋅⋅N distances) is not reflected in the appearance of the expected fourteen IR bands in the region of the OD stretching vibrations of the isotopically isolated HDO molecules. This must be due to the existence in the structure of several Ow⋅⋅⋅O or Ow⋅⋅⋅N hydrogen bonds with very similar strengths causing an overlap of the corresponding bands in the spectrum. Despite the presence of two carbonyl groups with practically identical C–O distances [124.2(3) and 124.0(3) pm], two clearly separated bands are registered in the carbonyl stretching region of the IR (1660 and 1627 cm–1) and Raman spectrum (1648 and 1620 cm–1). On the other hand, although two nonequivalent SO2 groups are present in the structure of Mg(sac)2⋅7H2O, only one pair of bands due to SO2 stretchings [νas(SO2 and νs(SO2) modes] is registered in the IR spectrum.


1999 ◽  
Vol 54 (6) ◽  
pp. 747-750 ◽  
Author(s):  
Joachim Pickardt ◽  
Pirka Wischlinski

Crystals o f the complex [K (benzo-18-crown-6][Zn(CN)3] H2O were obtained from a solution o f Zn(CN)2, KCN, and benzo-18-crown-6 in water/methanol. The compound crystallizes in the triclinic space group PI (no. 2),: Z = 2, a = 818,6(5), b = 1236,7(8), c = 1359,6(6) pm, a = 67,02(4), β = 87,38(4), 7 = 75,46(5). Each Zn atom is bonded to one bridging cyanide ion to give chains -Zn(CN)Zn -, and to two terminal CN groups. The N atom of one of the terminal CN groups interacts with a potassium ion o f the [K (benzo-18-crown-6)]+ unit. The coordination spheres of the K ions are completed by water molecules, which in turn form hydrogen bonds to N atoms of terminal CN groups of neighbouring chains, whereby puckered sheets are formed


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