scholarly journals New structural and spectroscopic data for eosphorite

1993 ◽  
Vol 57 (387) ◽  
pp. 329-336 ◽  
Author(s):  
M. A. Hoyos ◽  
T. Calderon ◽  
I. Vergara ◽  
J. Garcia-Solé
Keyword(s):  
Crystal Structure ◽  
Optical Absorption ◽  
Excitation Spectrum ◽  
Spectroscopic Data ◽  
Broad Band ◽  
Emission Lines ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

AbstractX-ray diffraction refinement of the crystal structure of eosphorite has been carried out with reference to the orthorhombic space group Cmca. The structure is similar to that previously described by Hanson (1960), but the standard deviations are improved. Optical absorption and photoluminescence have also been studied for this mineral. Two sharp emission lines, denoted as R1 and R2, superimposed to a broad band (630-750 nm) have been related to the presence of Cr3+ ions. The excitation spectrum of these emissions confirms that the absorption (excitation) bands centred at 431 nm and 585 are related to with 4A2 → 4T1 and 4A2 → 4T2 spin allowed transitions of this ion.

scholarly journals β-Y(BO2)3 – a new member of the β-Ln(BO2)3 (Ln=Nd, Sm, Gd–Lu) structure family

2017 ◽  
Vol 72 (12) ◽  
pp. 983-988 ◽  
Author(s):  
Martin K. Schmitt ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

Abstractβ-Y(BO2)3 was synthesized in a Walker-type multianvil module at 5.9 GPa/1000°C. The crystal structure has been elucidated through single-crystal X-ray diffraction. β-Y(BO2)3 crystallizes in the orthorhombic space group Pnma (no. 62) with the lattice parameters a=15.886(2), b=7.3860(6), and c=12.2119(9) Å. Its crystal structure will be discussed in the context of the isotypic lanthanide borates β-Ln(BO2)3 (Ln=Nd, Sm, Gd–Lu).

The X-Ray Crystal Structure of 1,2-3,4-Di-O-isopropylidene-4-C-methylthiomethoxy-β-L-arabino-hexoseptanos-5-ulose

1990 ◽  
Vol 43 (12) ◽  
pp. 2083 ◽  
Author(s):  
DC Craig ◽  
VJ James ◽  
JD Stevens
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Membered Ring ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

The crystal structure of the title compound (1) has been determined by X-ray diffraction. Crystals of (1) are orthorhombic, space group P21212 with a 11.425(1), b 24.916(1), c 5.8952(3)Ǻ, Z 4. Refinement on 1675 observed reflections measured with Cu Kα radiation converged at R 0.034. The seven- membered ring adopts a boat conformation in which the pseudo plane of symmetry passes through the ring oxygen.

Preparation and Structure of Tetraphenylarsonium Tris(1,2-dicyanoethenedithiolato)technetate(IV)

1988 ◽  
Vol 41 (7) ◽  
pp. 1127 ◽  
Author(s):  
SF Colmanet ◽  
MF Mackay
Keyword(s):  
Crystal Structure ◽  
Distorted Octahedron ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Ethanol Yields

The reaction of sodium 1,2-dicyanoethenedithiolate [( mnt )Na2] with (NH4)2 [TcBr6] in ethanol yields crystals of (AsPh4)2 [ Tc ( mnt )3] (1) after precipitation with AsPh4Cl. The crystal structure of (1) has been determined by X-ray diffraction. Crystals are orthorhombic, space group Pbcn , a 20.256(1), b 15.513(1), c 18.274(1)Ǻ, Z 4. Refinement on 2910 diffractometer data measured with Cu Kα radiation converged at R 0.056. The structure consists of [ Tc ( mnt )3]2- anions and (AsPh4)+ cations . The technetium(IV) atom is coordinated to six sulfur atoms to give a distorted octahedron.

Polysulfonylamine, CIII [1] Ein Hydroxylamin mit bemerkenswert kurzer O-N-B Bindung: Kristall- und Molekülstruktur von MeO-N(SO2Me)2 / Polysulfonylamines, C III [1] A Hydroxylamine with a Remarkably Short O-N Bond: Crystal and Molecular Structure of MeO-N(SO2Me)2

1998 ◽  
Vol 53 (5-6) ◽  
pp. 634-636 ◽  
Author(s):  
Martina Näveke ◽  
Armand Blaschette ◽  
Peter G. Jones
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Low Temperature ◽  
Title Compound ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Bond Angles

Abstract The crystal structure of the known title compound was determined by low-temperature X-ray diffraction (orthorhombic, space group Pbcn, Z = 4). The molecule displays an unusually short O-N bond, a relatively long C-O bond and a moderately pyramidal O-NS2 skeleton (O-N 133.1, C-O 148.5 pm, sum of bond angles at N: 347.4°).

Strukturen und Schwingungsspektren des Tetramethylammonium -a -dodekawolframatosilikats und des Tetrabutylammonium-β-dodekawolframatosilikats / Structures and Vibrational Spectra of Tetramethylammonium a-Dodecatungstosilicate and Tetrabutylammonium β-Dodecatungstosilicate

1981 ◽  
Vol 36 (2) ◽  
pp. 161-171 ◽  
Author(s):  
Joachim Fuchs ◽  
Axel Thiele ◽  
Rosemarie Palm
Keyword(s):  
Crystal Structure ◽  
Vibrational Spectra ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Crystal Water ◽  
Space Group ◽  
X Ray ◽  
First Time

Abstract Dodecatungstosilicates free of crystal water were prepared for the first time by using tetraalkylammonium as cation. The crystal structure of the tetramethylammonium a-dodeeatungstosilicate [N(CH3)4]4SiW12O40 (1) and tetrabutylammonium) β-dodecatungstosilicate, [N(C4H9)4]4SiWi2040 (2) were solved by X-ray diffraction. (1) crystallizes tetragonal in the space group 14̅ with lattice parameters a = 14.642 Å; c= 12.706 Å; (2) orthorhombic, space group P212121 with a = 29.277 Å, b = 22.181 Å and c = 15.381 Å. The differences between the two isomeric heteropolyanions are discussed, especially the distances and angles between the tungsten atoms. Comparison of characteristic differences in the vibrational spectra permits the identification of the isomeric anions.

Die Kristallstruktur von [Ca(N3)2(H2O)2] · C6H14N4 bei 100 K /The Crystal Structure of [Ca(N3)2(H2O)2] · C6H14N4 at 100 K

1989 ◽  
Vol 44 (2) ◽  
pp. 135-138 ◽  
Author(s):  
Franz A. Mautner ◽  
Harald Krischner ◽  
Christoph Kratky
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

Abstract The crystal structure of calcium azide dihydrate trans-bicyclo-[4.4.0]-1,4,6.9-tetraazadecane has been determined by single crystal X-ray diffraction at 100 K. [Ca(N3)2(H2O)2 (C6H14N4 crystallizes in the orthorhombic space group Pnma, Z = 4. with a - 1396.6(5), b = 1407.1(5), c = 712.2(2) pm. Calcium is hexacoordinated to four azide groups and two water molecules. The elongated octahedra are linked via μ(1,3)-bridging azide ions to form monolayers parallel to the ac-plane. The C6H14N4 molecules are arranged between these layers.

Crystal Structure of Dibromo(η4-1,5-cyclooctadiene)palladium(II)

1996 ◽  
Vol 61 (9) ◽  
pp. 1335-1341 ◽  
Author(s):  
Petr Štěpnička ◽  
Ivana Císařová
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Square Planar ◽  
Twisted Boat

The crystal structure of [(η4-C8H12)PdBr2] has been determined by a single crystal X-ray diffraction with R = 3.82% for 2 147 independent diffractions. The compound crystallizes with the symmetry of orthorhombic space group P212121 (No. 19) within the following parameters: a = 7.0785(5) Å, b = 11.1896(9) Å, c = 12.514(1) Å, V = 991.2(1) Å3, Z = 4. The square planar arrangement of ligands around Pd(II) is distorted due to the steric requirements of 1,5-cyclooctadiene in a twisted boat conformation. Formula units are joined by the weak C2-H2...Br1(1 + x, y, z) hydrogen bonds.

Synthesis and Crystal Structure of Pergolide Sulfoxide

1998 ◽  
Vol 63 (6) ◽  
pp. 803-812 ◽  
Author(s):  
Jan Čejka ◽  
Zdeněk Horák ◽  
Svetlana Pakhomova ◽  
Bohumil Kratochvíl ◽  
Petr Sedmera ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Peroxide ◽  
Ergot Alkaloids ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
X Ray

Pergolide sulfoxide (1), a metabolite of pergolide (2), has been prepared by oxidation of 2 with hydrogen peroxide. Its structure was determined by X-ray diffraction and compared with the structures of related ergot alkaloids. Two molecules of pergolide (S)- and (R)-sulfoxide crystallize with one molecule of water in the orthorhombic space group P212121 with a = 12.216(3) Å, b = 13.733(2) Å, c = 22.186(6) Å, Z = 4, V = 3 722(2) Å3.

The crystal structure of the methyl-bridged yttrium-aluminium complex, [(η-C5H5)2YMe2AlMe2]

1978 ◽  
Vol 31 (2) ◽  
pp. 411 ◽  
Author(s):  
GR Scollary
Keyword(s):  
Crystal Structure ◽  
Structural Analysis ◽  
Least Squares ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Yttrium Aluminium

A structural analysis of [(η-C5H5)2YMe2AlMe2] has been carried out by X- ray diffraction. Crystals are orthorhombic, space group Pna21, a 17.969(6), b 7.988(4), c 10.870(4) Ǻ, Z 4. The structure has been refined by a full-matrix least-squares procedure to R 0.052 for 663 observed reflections (Mo Kα automatic diffractometry). The structure contains a dimethyl bridge, the average bridging bond distances being 2.58(3) Ǻ for Y-C and 2.10(2) Ǻ for Al-C, and the Y-Al separation is 3.056(6) Ǻ.

Die Kristallstruktur von [Mg(H2O)6](N3)2 / The Crystal Structure of [Mg(H2O)6](N3)2

1986 ◽  
Vol 41 (8) ◽  
pp. 935-937 ◽  
Author(s):  
Franz A. Mautner ◽  
Harald Krischner ◽  
Christoph Kratky
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Single Crystal ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Metal Atoms

Abstract The crystal structure of [Mg(H2O)6](N3)2 was determined by single crystal X-ray diffraction (421 independent observed MoKα-counter reflections. R = 0.037). The crystals are orthorhombic, space group Fmmm, Z = 4, a = 644.3(1), b = 1134.4(1), c = 1333.5(3) pm. The magnesium atoms are octahedrally coordinated to six oxygen atom s of water molecules, the azide groups are not coordinated to metal atoms, N -N = 117.0(2) pm.

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