scholarly journals Crystal Structure of Triclinic Colchiceine Hemihydrate

1985 ◽  
Vol 38 (3) ◽  
pp. 413 ◽  
Author(s):  
Maureen F Mackay ◽  
James D Morrison ◽  
Jacqueline M Gulbis
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
The Other ◽  
Water Molecules ◽  
Space Group

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.

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

1988 ◽  
Vol 52 (365) ◽  
pp. 247-255 ◽  
Author(s):  
Stefano Merlino
Keyword(s):  
Crystal Structure ◽  
The Other ◽  
Water Molecules ◽  
Charge Balance ◽  
Alkali Cations ◽  
Structural Units ◽  
Tetrahedral Sheet ◽  
Space Group

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.

Untersuchungen an Polyhalogeniden, XXXXII [1]. Das Pentaiodid-Ion I5-; Eine Übersicht: Darstellung und Kristallstruktur der Verbindung [Rb(C16H24O6)](I5) · H2O

2001 ◽  
Vol 56 (3) ◽  
pp. 271-280 ◽  
Author(s):  
Ingo Pantenburg ◽  
Karl-Friedrich Tebbe
Keyword(s):  
Crystal Structure ◽  
The Other ◽  
Trans Configuration ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Zigzag Chain ◽  
Space Group ◽  
Independent Molecules

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.

scholarly journals Darstellung und Kristallstruktur von Erdalkalidicyanoargentaten M[Ag(CN)2]2 • 2 H2O (M = Ca, Sr) / Properties and Crystal Structure of Alkaline-Earth Dicyanoargentates M[Ag(CN)2]2 • 2 H2O (M = Ca, Sr)

1985 ◽  
Vol 40 (12) ◽  
pp. 1618-1621 ◽  
Keyword(s):  
Crystal Structure ◽  
Alkaline Earth ◽  
Structural Model ◽  
Direct Methods ◽  
Trigonal Prism ◽  
Water Molecules ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Tricapped Trigonal Prism ◽  
Fractionated Crystallization

Abstract Alkaline-earth dicyanoargentates M[Ag(CN)2]2 • 2H2O (M = Ca. Sr) were synthesized by reaction of M(ClO4)2 with K[Ag(CN)2] and subsequent fractionated crystallization. The colourless, light-sensitive crystals are orthorhombic, space group Pbcm, with a = 8.435(1) Å, b - 6.3985(6) Å , c = 18.584(2) Å , Z = 4 (M = Ca), and a = 8.0032(8) Å, b = 6.8688(5) Å, c = 18.870(1) Å , Z = 4 (M = Sr). A structural model derived from Direct Methods was refined to R = 0.064 and R = 0.044. rsp. The structure of the two isotypic compounds comprises layers of [Ag(CN)2]“ dumb-bells, arranged in such a way, that trigonal prisms of nitrogen are formed. These prisms are occupied by the alkaline-earth ions. Three oxygen atoms from neighbouring water molecules complete a tricapped trigonal prism around Ca2+ and Sr2+

The preparation and crystal structure of pentaiodinium hexafluoroantimonate(V) containing I153+

1979 ◽  
Vol 57 (9) ◽  
pp. 968-973 ◽  
Author(s):  
Jack Passmore ◽  
Peter Taylor ◽  
Tom Whidden ◽  
Peter S. White
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Direct Methods ◽  
Multiple Solution ◽  
The Other ◽  
Full Matrix ◽  
Space Group ◽  
Bond Angles

Crystalline pentaiodinium hexafluoroantimonate was prepared by the reaction of I2 and SbF5 in AsF3. The crystals were triclinic, a = 8.295(4) Å, b = 15.61(1) Å, c = 8.390(4) Å, α = 81.49(4)°, β = 110.02(4)°, γ = 85.06(4)°, Z = 3, space group [Formula: see text]. The structure was solved by multiple-solution direct methods and Fourier syntheses and refined by full-matrix and blocked-matrix least-squares procedures to a final R of 0.062 and Rw of 0.090 for 2229 reflections with I ≥ 3σ(I). The two crystallographically independent planar, bent I5+ chains (one centrosymmetric, the other essentially centrosymmetric), each have two collinear central bonds of 2.899(2) Å (× 2); 2.896(2), and 2.920(2) Å, bond angles 180° and 178.7(6)°, respectively, and two shorter terminal bonds of 2.680(3) Å (× 2); 2.666(3) and 2.698(2) Å, with bond angles between central and terminal bonds of 94.53(6)° (× 2); 93.86(7) and 93.17(7)°, respectively. Three I5+ units are joined by a weak (3.416(3) Å) interaction to form what may be regarded as an I153+ unit. The SbF6− anions are approximately octahedral.

Darstellung und Kristallstruktur von Rubidiumdicyanoargentat (I), Rb[Ag(CN)2] · 0,4H2O / Synthesis Crystal Structure of Rubidium Dicyanoargentate (I), Rb[Ag(CN)2] · 0,4H2O

1993 ◽  
Vol 48 (2) ◽  
pp. 133-139
Author(s):  
Sabine Kühnei ◽  
Klaus-Jürgen Range
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
Water Molecules ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Silver Cyanide ◽  
Trigonal Prismatic ◽  
Silver Atoms

AbstractRb[Ag(CN)2] · 0,4H2O was synthesized by reaction of silver cyanide with RbOH and liquid HCN at 0 °C. The colourless crystals are orthorhombic, space group Cmc21, with a = 14.440(3), b = 17.645(1), c = 14.799(1) Å and Z = 32. The structure was solved by Patterson and standard direct methods and refined to R = 0.060 and Rw = 0.051, respectively, for 2204 absorption-corrected unique reflections with F > σ(F). The structure comprises slightly buckled layers of linear [Ag(CN)2]- groups, in which silver atoms are arranged in three- and eight-membered rings. The shortest Ag -Ag distance is 3.05 Å. The rubidium ions are arranged in trigonal-prismatic, cubic and square-antiprismatic sites. Additional cavities contain the water molecules.

Crystal structure determination of the conformation of two bicyclo[3.3.1]nonan-ones

1985 ◽  
Vol 63 (6) ◽  
pp. 1166-1169 ◽  
Author(s):  
John F. Richardson ◽  
Ted S. Sorensen
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Molecular Structures ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Final Agreement

The molecular structures of exo-7-methylbicyclo[3.3.1]nonan-3-one, 3, and the endo-7-methyl isomer, 4, have been determined using X-ray-diffraction techniques. Compound 3 crystallizes in the space group [Formula: see text] with a = 15.115(1), c = 7.677(2) Å, and Z = 8 while 4 crystallizes in the space group P21 with a = 6.446(1), b = 7.831(1), c = 8.414(2) Å, β = 94.42(2)°, and Z = 2. The structures were solved by direct methods and refined to final agreement factors of R = 0.041 and R = 0.034 for 3 and 4 respectively. Compound 3 exists in a chair–chair conformation and there is no significant flattening of the chair rings. However, in 4, the non-ketone ring is forced into a boat conformation. These results are significant in interpreting what conformations may be present in the related sp2-hybridized carbocations.

Structure of 3α,4α:5β,6β-Diepoxyandrostan-17-one

1983 ◽  
Vol 36 (11) ◽  
pp. 2333 ◽  
Author(s):  
B Kamenar ◽  
RA Pauptit ◽  
JM Waters
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Direct Methods ◽  
Monoclinic Space Group ◽  
Space Group ◽  
X Ray

The X-ray crystal structure of 3α,4α:5β,6β-diepoxyandrostan-17-one has been determined. Crystals of the title compound (C19H26O3)are monoclinic, space group P21, with a 9.208(2), b 9.620(4), c 9.312(3) �, β 99.14(2)�, V 814.5 Ǻ3 and Z 2. The structure was solved by direct methods and refined to R 0.039 for 887 observed reflexions. The 3α,4α:5β,6β configuration of the epoxide rings confirms the assignment based on proton n.m.r. studies.

Crystal Structure of Calcium Picrate Pentahydrate: A New Eight-Coordinate Stereochemistry for [M(bidentate)2(unidentate)4]

1979 ◽  
Vol 32 (2) ◽  
pp. 301 ◽  
Author(s):  
V Diakiw ◽  
TW Hambley ◽  
DL Kepert ◽  
CL Raston ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Water Molecule ◽  
Single Crystal ◽  
Title Compound ◽  
Lattice Site ◽  
The Other ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Triangular Face ◽  
X Ray

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.

A novel one-dimensional CoIIcoordination polymer:catena-poly[[hexaaquacobalt(II)] [[diaquabis(sulfato-κO)cobalt(II)]-μ-4,4′-bipyridine-κ2N:N′] [[triaqua(sulfato-κO)cobalt(II)]-μ-4,4′-bipyridine-κ2N:N′]]

2012 ◽  
Vol 68 (9) ◽  
pp. m265-m268 ◽  
Author(s):  
Kai-Long Zhong ◽  
Ming-Yi Qian
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
The Other ◽  
Water Molecules ◽  
Supramolecular Network ◽  
Sulfate Ion ◽  
Sulfate Ions ◽  
One Dimensional ◽  
The Third ◽  
Hydrogen Bonding Interactions

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.

Die Kristallstruktur des Lithium-Benzamidinats {Li3[C6H5 - C(NSiMe3)2]3 · NC - C6H5} / The Crystal Structure of the Lithium Phenylamidinate {Li3[C6H5 - C(NSiMe3)2]3 · NC - C6H5}

1994 ◽  
Vol 49 (10) ◽  
pp. 1444-1447 ◽  
Author(s):  
Helmut Goesmann ◽  
Dieter Fenske
Keyword(s):  
Crystal Structure ◽  
Nitrogen Atom ◽  
Single Crystals ◽  
Title Compound ◽  
The Other ◽  
Space Group ◽  
Structure Solution

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.

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