Trifluoromethyl Complexes of Osmium(II) by Halogen Oxidation of an Osmium(0) Difluorocarbene Compound and the Structures of Os(CF3)Cl2(NO)(PPh3)2 and Os(CF3)Cl0.666I1.333(NO)(PPh3)2

1986 ◽  
Vol 39 (9) ◽  
pp. 1315 ◽  
Author(s):  
GR Clark ◽  
TR Greene ◽  
WR Roper
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Crystal Structures ◽  
Octahedral Coordination ◽  
Space Group ◽  
Twofold Axis

Oxidation of Os(=CF2) Cl (NO)(PPh3)2 by the halogens X2(X = Cl , I), unexpectedly yields the trifluoromethyl complexes Os(CF3)CIX(NO)(PPh3)2 in a low yield which is improved by the addition of LiF to the reaction mixture. The crystal structures of both Os(CF3)Cl2(NO)(PPh3)2 and Os(CF3)Cl0.666I1.333(NO)(PPh3)2 have been determined. Crystals of Os(CF3)Cl2(NO)(PPh3)2 are monoclinic, a 24.543(5), b 9.685(1), c 15.951(1) Ǻ, β 115.81(1)°, Z 4, space group C2/c. Least-squares refinement has returned a residual, R, of 0.048 for 3371 observed reflections. The molecule lies on a twofold axis, with the CF3-group and one Cl-ligand statistically interchanged. Crystals of Os(CF3)Cl0.666 I1.333(NO)(PPh3)2 are monoclinic, a 24.562(4), b 9.690(1), c 16.385(2) Ǻ, β 115.51(1)°, Z 4, space group C2/c. Least-squares refinement has returned a residual of 0.058 for 4087 observed reflections. This crystal structure is best described as a 2 : 1 mixture of Os(CF3) ClI (NO)(PPh3)2 and s(CF3)I2(NO)(PPh3)2, (both with CF3 and I statistically disordered about the diad axis, as above). Both complexes exhibit octahedral coordination geometries.

Polymorphism and photoluminescence properties of K3ErSi2O7

2019 ◽  
Vol 75 (10) ◽  
pp. 1417-1423
Author(s):  
Predrag Dabić ◽  
Marko G. Nikolić ◽  
Sabina Kovač ◽  
Aleksandar Kremenović
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Three Dimensional ◽  
Green Emission ◽  
The Other ◽  
Octahedral Coordination ◽  
Hexagonal Prism ◽  
Photoluminescence Properties ◽  
Space Group ◽  
Trigonal Prismatic Coordination

Two polymorphs of tripotassium erbium disilicate, K3ErSi2O7, were synthesized by high-temperature flux crystal growth during the exploration of the flux technique for growing new alkali rare-earth elements (REE) containing silicates. Their crystal structures were determined by single-crystal X-ray diffraction analysis. One of them (denoted 1) crystallizes in the space group P63/mmc and is isostructural with disilicates K3LuSi2O7, K3ScSi2O7 and K3YSi2O7, while the other (denoted 2) crystallizes in the space group P63/mcm and is isostructural with disilicates K3NdSi2O7, K3REESi2O7 (REE = Gd–Yb), K3YSi2O7, K3(Y0.9Dy0.1)Si2O7 and K3SmSi2O7. In the crystal structure of polymorph 1, the Er cations are in an almost perfect octahedral coordination, while in the crystal structure of polymorph 2, part of the Er cations are in a slightly distorted octahedral coordination and the other part are in an ideal trigonal prismatic coordination environment. Sharing six corners, disilicate Si2O7 groups in the crystal structure of polymorph 1 link six ErO6 octahedra, forming a three-dimensional network and nine-coordinated potassium cations are located in its holes. In the crystal structure of polymorph 2, the disilicate Si2O7 groups connect four ErO6 octahedra, as well as one ErO6 trigonal prism. Three differently coordinated potassium cations are situated between them. Different site symmetries of the erbium cations in the crystal structures of polymorphs 1 and 2 affect their photoluminescence properties. Only polymorph 2 exhibits luminescence. Intense narrow lines in the emission spectrum are a result of the 4f–4f transition. The green emission line at 560 nm is the result of the Er3+ transition 4S3/2→4I15/2, and the luminescence line at 690 nm is the result of a 4F9/2→4I15/2 transition. The crystal morphologies of the two polymorphs are similar. Crystals of polymorph 1 are in the form of a hexagonal prism in combination with a hexagonal base, while crystals of polymorph 2 contain a dihexagonal prism in combination with a hexagonal base, although poorly developed faces of the dihexagonal pyramid can also be noticed.

Notizen: Über die Kristallstruktur von β-SCl3+SbCl6- und interionischen Wechselwirkungen in SCl3+-Salzen/The Crystal Structure of β-SCl3+SbCl6- and Interionic Interactions in SCl3+ Salts

1992 ◽  
Vol 47 (4) ◽  
pp. 594-596 ◽  
Author(s):  
Rolf Minkwitz ◽  
Andreas Kornath ◽  
Hans Preut
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Unit Cell ◽  
Octahedral Coordination ◽  
Monoclinic Space Group ◽  
Space Group ◽  
Distorted Octahedral Coordination ◽  
Distorted Octahedral ◽  
Interionic Interactions

Chlorosulfonium hexachloroantimonate crystallizes in the monoclinic space group C 2/m with a = 1405.5(3) pm, b = 1055.1(2) pm , c = 882.2(2) pm, β = 110.05(3)° at 169 K with 4 formula units per unit cell. A distorted octahedral coordination around sulphur is formed by three S - C l bonds and three interionic sulphur chlorine contacts. The interionic interactions in SCl3+ salts of known crystal structures are discussed.

Studies in aryltin chemistry. Part 6. Crystal and molecular structures of tetra(p-methylsulphonylphenyl)tin(IV) and tetra(p-methylsulphinylphenyl)tin(IV) monohydrate

1990 ◽  
Vol 68 (8) ◽  
pp. 1277-1282 ◽  
Author(s):  
Ivor Wharf ◽  
Michel G. Simard ◽  
Henry Lamparski
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
Direct Method ◽  
Molecular Structures ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Molecular Symmetry ◽  
Asymmetric Unit ◽  
Full Matrix ◽  
Space Group

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.

Structure of the Tris(diallyldithiocarbamate)cobalt(III) Complex

1992 ◽  
Vol 57 (2) ◽  
pp. 332-338 ◽  
Author(s):  
Eleonóra Kellö ◽  
Jan Lokaj ◽  
Viktor Vrábel
Keyword(s):  
Least Squares ◽  
Metal Atom ◽  
Least Squares Method ◽  
Heavy Atom ◽  
Distorted Octahedron ◽  
Monoclinic System ◽  
Space Group ◽  
Twofold Axis ◽  
Diagonal Approximation ◽  
Heavy Atom Method

The structure of [Co{S2CN(CH2-CH=CH2)2}3] was determined by the heavy atom method, all nonhydrogen atoms being refined by anisotropic diagonal approximation using the least squares method to the value of R= 0.067 for 1 024 reflections with I ≥ 1.96σ(I). The substance is isostructural with [Fe{S2CN(CH2-CH=CH2)2}3], crystallizes in the monoclinic system, space group C2/c, lattice parameters a = 1.8763(9), b = 1.0209(5), c = 1.5402(7) nm, β = 106.18(4)°, Z = 4. Cobalt is coordinated by 3 dithiocarbamate ligands in the bidentate way, the average Co-S lenght is 0.2267(2) nm. The metal atom and two ligand atoms are located on the twofold axis. The CoS6 polyhedron is a trigonally distorted octahedron.

79Br, 127I NQR of Diammoniumalkyl Halides and Piperazinium Halides. Crystal Structure of Piperazinium Dibromide Monohydrate and Piperazinium Monoiodide

1989 ◽  
Vol 44 (1) ◽  
pp. 41-55 ◽  
Author(s):  
Jutta Hartmann ◽  
Shi-Qi Dou ◽  
Alarich Weiss
Keyword(s):  
Crystal Structure ◽  
Phase Transitions ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Temperature Range

Abstract The 79Br and 127I NQR spectra were investigated for 1,2-diammoniumethane dibromide, -diiodide, 1,3-diammoniumpropane dibromide, -diiodide, piperazinium dibromide monohydrate, and piperazinium monoiodide in the temperature range 77 ≦ T/K ≦ 420. Phase transitions could be observed for the three iodides. The temperatures for the phase transitions are: 400 K and 404 K for 1,2-diammoniumethane diiodide, 366 K for 1,3-diammoniumpropane diiodide, and 196 K for piperazinium monoiodide.The crystal structures were determined for the piperazinium compounds. Piperazinium dibromide monohydrate crystallizes monoclinic, space group C2/c, with a= 1148.7 pm, 0 = 590.5 pm, c= 1501.6pm, β = 118.18°, and Z = 4. For piperazinium monoiodide the orthorhombic space group Pmn 21 was found with a = 958.1 pm, b = 776.9 pm, c = 989.3 pm, Z = 4. Hydrogen bonds N - H ... X with X = Br, I were compared with literature data.

Notizen: Darstellung und Kristallstruktur von α- und β-Cu3TiO4 / Preparation and Crystal Structure of α- and β-Cu3TiO4

1977 ◽  
Vol 32 (11) ◽  
pp. 1356-1357 ◽  
Author(s):  
Klaus-Jürgen Range ◽  
Fritz Ketterl
Keyword(s):  
Crystal Structure ◽  
Ternary System ◽  
Crystal Structures ◽  
Octahedral Coordination ◽  
Distorted Octahedral Coordination ◽  
Distorted Octahedral

A compound Cu3TiO4 was found to exist in the ternary system CuO-Cu2O-TiO2. The crystal structures of two modifications are very similar and contain Cu+ with linear, Cu2+ and Ti4+ with trigonal distorted octahedral coordination.

The crystal structure and vibrational spectra of cis-dichlorobis(cyclopropylamine)-platinum(II), PtCl2(C3H5NH2)2

1981 ◽  
Vol 59 (18) ◽  
pp. 2737-2745 ◽  
Author(s):  
Helen Elaine Howard-Lock ◽  
Colin James Lyne Lock ◽  
Graham Turner ◽  
Maruta Zvagulis
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Vibrational Spectra ◽  
Vibrational Analysis ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
Deuterated Analogue

Crystals of cis-dichlorobis(cyclopropylamine)platinum(II), PtCl2(C3H5NH2)2, are monoclinic, a = 12.770(5), b = 5.838(2), c = 15.113(6) Å, β = 104.46(3)°, Z = 4, space group P21/c. The structure was solved by Patterson and Fourier syntheses and was refined by full-matrix least-squares to R = 0.057, Rw = 0.055 for 1577 reflections with I > 3σ(I). Bond lengths and angles are normal. A vibrational analysis of the compound and its d2-deuterated analogue was performed.

Crystal structure determination for crystals with twinning by hemihedry or pseudohemihedry

1991 ◽  
Vol 194 (3-4) ◽  
Author(s):  
Takaharu Araki
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Structure Determination ◽  
Difficult Case ◽  
Proper Selection ◽  
Space Group ◽  
Geometrical Symmetry ◽  
Symmetry Space ◽  
Symmetry Space Group ◽  
Selection Of

AbstractAn approach to structure determination for a crystal from component crystals in equal volume fractions, the most difficult case to the solution, is outlined with precautions for stepwise initialization. Proper selection of a crystal geometrical symmetry space group from a corresponding twin anti-symmetry space group and interpretation of a Patterson space are indispensable prerequisite for the solution. Observations unique to the case are briefly described in a sequence of Patterson synthesis, Fourier approach and least-squares refinement for efficient interpretation and processing.

scholarly journals Die Kristallstruktur des Silbertetrachloroaurats(III) AgAuCl4 und seine kristallchemische Verwandtschaft zum Rubidiumtetrachloroaurat(III) RbAuCl4 / The Crystal Structure of Silver Tetrachloroaurate(III) AgAuCl4 and its Crystal Chemical Relationship to the Rubidium Tetrachloroaurate(III) RbAuCl4

1977 ◽  
Vol 32 (7) ◽  
pp. 741-744 ◽  
Author(s):  
Walther Werner ◽  
Joachim Strähle
Keyword(s):  
Crystal Structure ◽  
Bond Length ◽  
Octahedral Coordination ◽  
Monoclinic Space Group ◽  
Crystal Chemical ◽  
Space Group ◽  
Square Planar ◽  
Cl Atoms

AgAuCl4 crystallizes in the monoclinic space group I2/c with Zi = 4. The crystal structure is built up by Ag+ cations and square planar AuCl4⁻ anions with Au-Cl bond length of 228 pm. The Ag+ ions have an octahedral coordination of Cl atoms. AgAuCl4 is topologically related to RbAuCl4.

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