Crystal chemistry of inorganic compounds based on chains of oxocentered tetrahedra III. Crystal structure of georgbokiite, Cu5O2(SeO3)2Cl21

1999 ◽  
Vol 214 (3) ◽  
Author(s):  
S. V. Krivovichev ◽  
R. R. Shuvalov ◽  
T. F. Semenova ◽  
S. K. Filatov
Keyword(s):  
Crystal Structure ◽  
Chemical Composition ◽  
Crystal Chemistry ◽  
Inorganic Compounds ◽  
New Mineral ◽  
Monoclinic Crystal ◽  
Monoclinic Crystal Structure

AbstractThe monoclinic crystal structure of georgbokiite, a new mineral with the chemical composition Cu

Preparation, Crystal Structure, and Properties of the Lanthanoid Carbides Ln4C7 with Ln = Ho, Er, Tm, and Lu

1996 ◽  
Vol 51 (5) ◽  
pp. 646-654 ◽  
Author(s):  
Ralf Czekalla ◽  
Wolfgang Jeitschko ◽  
Rolf-Dieter Hoffmann ◽  
Helmut Rabeneck
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Magnetic Ordering ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Neutron Powder Diffraction Data ◽  
Monoclinic Crystal Structure ◽  
Arc Melting ◽  
Structure Factors ◽  
Hydrolysis Of

The isotypic carbides Ln4C7 (Ln = Ho, Er, Tm, Lu) were prepared by arc-melting of the elemental components, followed by annealing at 1300 °C. The positions of the metal and of some carbon atoms of the monoclinic crystal structure of LU4C7 were determined from X-ray powder data, and the last carbon positions were found and refined from neutron powder diffraction data: P21/c, a = 360.4(1), b = 1351.4(3), c = 629.0(2) pm, β = 104.97(2)°, Z = 2, R = 0.026 for 429 structure factors and 15 positional parameters. The structure contains isolated carbon atoms with octahedral lutetium coordination and linear C3-units, with C-C bond lengths of 132(1) and 135(1) pm. This carbide may therefore be considered as derived from methane and propadiene. The hydrolysis of LU4C7 with distilled water yields mainly methane and propine, while the hydrolyses of the corresponding holmium and erbium carbides resulted in relatively large amounts of saturated and unsaturated C2-hydrocarbons in addition to the expected products methane and propine. The structure comprises two-dimensionally infinite NaCl-type building elements, which are separated by the C3-units. It may be described as a stacking variant of a previously reported structure of HO4C7, now designated as the a-modification. The Lu4C7-type β -modification was obtained at higher temperatures. Its structure was refined by the Rietveld method from X-ray powder data to a residual R = 0.037 for 320 F values and 15 positional parameters. Lu4C7 is Pauli paramagnetic; β -HO4C7 and Er4C7 show Curie-Weiss behavior with magnetic ordering temperatures of less than 20 K.

trans-Bis(O-ethylxanthato)bis(triphenylphosphine)ruthenium(III) hexafluorophosphate monohydrate

2006 ◽  
Vol 62 (5) ◽  
pp. m1077-m1078
Author(s):  
Yuko Ohuchi ◽  
Kyoko Noda ◽  
Takayoshi Suzuki ◽  
Kazuo Kashiwabara ◽  
Hideo D. Takagi
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Complex Cation ◽  
Orthorhombic Crystal ◽  
Monoclinic Crystal ◽  
Monoclinic Crystal Structure

In the monoclinic crystal structure of the title compound, trans-[Ru(C3H5OS2)2(C18H15P)2]PF6·H2O, the structure of the RuIII complex cation is very similar to that in the orthorhombic crystal of the nonhydrated complex [Noda, Ohuchi, Hashimoto, Fujiki, Itoh, Iwatsuki, Noda, Suzuki, Kashiwabara & Takagi (2006), Inorg. Chem. 45, 1349–1355]. In the present crystal structure, the P—Ru—P bond axes of the complex cations are aligned parallel to the [101] direction.

The crystal structure of the new mineral wilhelmkleinite – ZnFe3+2(OH)2AsO4)2

2000 ◽  
Vol 215 (2) ◽  
Author(s):  
G. Adiwidjaja ◽  
K. Friese ◽  
K.-H. Klaska ◽  
P. B. Moore ◽  
J. Schlüter
Keyword(s):  
Crystal Structure ◽  
Chemical Composition ◽  
New Mineral ◽  
Orthorhombic Modification ◽  
The Face ◽  
The Common ◽  
Good Agreement

The new mineral wilhelmkleinite has ideal chemical composition ZnFeThe structure is characterized by chains of edge-linked [Fe(OH)Alternatively, one [ZnODistances and angles in wilhelmkleinite are in good agreement with values observed in comparable compounds. The face sharing of the octahedra leads to a pronounced shortening of the common edges.Wilhelmkleinite is closely related to the orthorhombic modification of CuFe

Electron density, disorder and polymorphism: high-resolution diffraction studies of the highly polymorphic neuralgic drug carbamazepine

2016 ◽  
Vol 72 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Ioana Sovago ◽  
Matthias J. Gutmann ◽  
Hans Martin Senn ◽  
Lynne H. Thomas ◽  
Chick C. Wilson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Diffraction Data ◽  
Structural Formula ◽  
Orthorhombic Crystal ◽  
Monoclinic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Monoclinic Crystal Structure

Analysis of neutron and high-resolution X-ray diffraction data on form (III) of carbamazepine at 100 K using the atoms in molecules (AIM) topological approach afforded excellent agreement between the experimental results and theoretical densities from the optimized gas-phase structure and from multipole modelling of static theoretical structure factors. The charge density analysis provides experimental confirmation of the partially localized π-bonding suggested by the conventional structural formula, but the evidence for any significant C—N π bonding is not strong. Hirshfeld atom refinement (HAR) gives H atom positional and anisotropic displacement parameters that agree very well with the neutron parameters. X-ray and neutron diffraction data on the dihydrate of carbemazepine strongly indicate a disordered orthorhombic crystal structure in the space groupCmca, rather than a monoclinic crystal structure in space groupP21/c. This disorder in the dihydrate structure has implications for both experimental and theoretical studies of polymorphism.

Crystal structure and crystal chemistry of biehlite, Sb1.79As0.21MoO6

2000 ◽  
Vol 215 (9) ◽  
Author(s):  
G. Adiwidjaja ◽  
Karen Friese ◽  
K.-H. Klaska ◽  
J. Schlüter ◽  
M. Czank
Keyword(s):  
Crystal Structure ◽  
Crystal Chemistry ◽  
Lone Pair ◽  
New Mineral ◽  
Calculated Distance ◽  
Oxygen Atoms

The new mineral biehlite was found in the Tsumeb mine, Namibia and has the composition Sb[MoOThe [MoOThe Sb-cation forms three short bonds with oxygen at distances slightly smaller than 2Å. Six further oxygen atoms are located at distances ranging from 2.910(6) to 3.470(6)Å. Calculated distance for the lone-pair is 1.18 Å. Part of the Sb

scholarly journals The monoclinic crystal structure form of bacterioferritin fromE. coli

1996 ◽  
Vol 52 (a1) ◽  
pp. C177-C177
Author(s):  
M. Hospital ◽  
A. Dautant ◽  
J. Yariv ◽  
G. Précigoux ◽  
A. J. Kalb (Gilboa) ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structure Form ◽  
Monoclinic Crystal ◽  
Monoclinic Crystal Structure

New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XI. Anatolyite, Na6(Ca,Na)(Mg,Fe3+)3Al(AsO4)6

2019 ◽  
Vol 83 (5) ◽  
pp. 633-638 ◽  
Author(s):  
Igor V. Pekov ◽  
Inna S. Lykova ◽  
Vasiliy O. Yapaskurt ◽  
Dmitry I. Belakovskiy ◽  
Anna G. Turchkova ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Chemical Composition ◽  
Electron Microprobe ◽  
New Mineral ◽  
Single Crystal Xrd ◽  
Xrd Pattern ◽  
Potassic Feldspar ◽  
Tolbachik Volcano ◽  
Mohs Hardness ◽  
Heteropolyhedral Framework

AbstractThe new mineral anatolyite Na6(Ca,Na)(Mg,Fe3+)3Al(AsO4)6 was found in the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. It is associated with potassic feldspar, hematite, tenorite, cassiterite, johillerite, tilasite, ericlaxmanite, lammerite, arsmirandite, sylvite, halite, aphthitalite, langbeinite, anhydrite, wulffite, krasheninnikovite, fluoborite, pseudobrookite and fluorophlogopite. Anatolyite occurs as aggregates (up to 2 mm across) of rhombohedral–prismatic, equant or slightly elongated along [001] crystals up to 0.2 mm. The mineral is transparent, pale brownish–pinkish, with vitreous lustre. It is brittle, cleavage was not observed and the fracture is uneven. The Mohs’ hardness is ca 4½. Dcalc is 3.872 g cm–3. Anatolyite is optically uniaxial (–), ω = 1.703(4) and ε = 1.675(3). Chemical composition (wt.%, electron microprobe) is: Na2O 16.55, K2O 0.43, CaO 2.49, MgO 5.80, MnO 0.16, CuO 0.69, ZnO 0.55, Al2O3 5.01, Fe2O3 7.94, TiO2 0.18, SnO2 0.17, SiO2 0.04, P2O5 0.55, As2O5 60.75, SO3 0.03, total 101.34. The empirical formula based on 24 O apfu is (Na5.90K0.10)Σ6.00(Ca0.50Na0.13Zn0.08Mn0.03)Σ0.74(Mg1.63Fe3+1.12Al0.15Cu0.10)Σ3.00(Al0.96Ti0.03Sn0.01)Σ1.00(As5.97P0.09Si0.01)Σ6.07O24. Anatolyite is trigonal, R$\bar{3}$c, a = 13.6574(10), c = 18.2349(17) Å, V = 2945.6(4) Å3 and Z = 6. The strongest reflections of the powder XRD pattern [d,Å(I)(hkl)] are: 7.21(33)(012), 4.539(16)(113), 4.347(27)(211), 3.421(20)(220), 3.196(31)(214), 2.981(17)(223), 2.827(100)(125) and 2.589(18)(410). The crystal structure was solved from single-crystal XRD data to R = 4.77%. The structure is based on a 3D heteropolyhedral framework formed by M4O18 clusters [M1 = Al and M2 = (Mg,Fe3+)] linked with AsO4 tetrahedra. (Ca,Na) and Na cations centre A1O6 and A2O8 polyhedra in voids of the framework. Anatolyite is isostructural with yurmarinite. The new mineral is named in honour of the outstanding Russian crystallographer, mineralogist and mathematician Anatoly Kapitonovich Boldyrev (1883–1946).

scholarly journals A new crystalline form of αβ-D-lactose prepared by oven drying a concentrated aqueous solution of D-lactose

2019 ◽  
Vol 75 (7) ◽  
pp. 904-909 ◽  
Author(s):  
Daniel Nicholls ◽  
Carole Elleman ◽  
Norman Shankland ◽  
Kenneth Shankland
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Three Dimensional ◽  
Crystalline Form ◽  
X Ray Diffraction ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Monoclinic Crystal Structure ◽  
High Degree ◽  
Triclinic Form

A new crystalline form of αβ-D-lactose (C12H22O11) has been prepared by the rapid drying of an approximately 40% w/v syrup of D-lactose. Initially identified from its novel powder X-ray diffraction pattern, the monoclinic crystal structure was solved from a microcrystal recovered from the generally polycrystalline mixed-phase residue obtained at the end of the drying step. This is the second crystalline form of αβ-D-lactose to be identified and it has a high degree of structural three-dimensional similarity to the previously identified triclinic form.

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