scholarly journals Polymorphie von Cs3Tl2Br9

1987 ◽  
Vol 42 (7) ◽  
pp. 818-824 ◽  
Author(s):  
Klaus Zimmermann ◽  
Gerhard Thiele
Keyword(s):  
Phase Transition ◽  
Thermal Analysis ◽  
Low Temperature ◽  
Aqueous Solutions ◽  
Closed System ◽  
Type Structure ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

Abstract Cs3Tl2Br9, which has been synthesized either by heating a 3:2 mixture of CsBr/TlBr with bromine in a closed system or by reaction of these components in aqueous solutions, shows dimorphism. The phase transition (170 °C) was characterized by thermal analysis and X-ray diffraction. The low temperature modification α-Cs3TlBr9 crystallizes in the monoclinic space group P21/m (a = 964.98(9), b = 779.49(7), c = 1382.16(13) pm, β = 92.68(1)°, Z = 2). The structure is built up from TlBr6 octahedra linked by sharing vertices to chains and isolated TlBr4 tetrahedra. The high tem perature modification β-Cs3Tl2Br9 represents the undistorted trigonal Cs3Bi2Br9-type structure (a = 796.80(8), c - 982.98(15) pm).

Silver(I)-Saccharinato Complexes with 2-(Aminomethyl)pyridine and 2-(2-Aminoethyl)pyridine Ligands: [Ag(sac)(ampy)] and [Ag2(sac)2(μ-aepy)2]

2005 ◽  
Vol 60 (9) ◽  
pp. 978-983 ◽  
Author(s):  
Sevim Hamamci ◽  
Veysel T. Yilmaz ◽  
William T. A. Harrison
Keyword(s):  
Thermal Analysis ◽  
Hydrogen Bonds ◽  
Monoclinic Space Group ◽  
Stacking Interactions ◽  
Coordination Geometry ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Pyridine Ligands

Two new saccharinato-silver(I) (sac) complexes, [Ag(sac)(ampy)] (1), and [Ag2(sac)2(μ-aepy)2] (2), [ampy = 2-(aminomethyl)pyridine, aepy = 2-(2-aminoethyl)pyridine], have been prepared and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X-ray diffraction. Complexes 1 and 2 crystallize in the monoclinic space group P21/c and triclinic space group P1̄, respectively. The silver(I) ions in both complexes 1 and 2 exhibit a distorted T-shaped AgN3 coordination geometry. 1 consists of individual molecules connected into chains by N-H···O hydrogen bonds. There are two crystallographically distinct dimers in the unit cell of 2 and in each dimer, the aepy ligands act as a bridge between two silver(I) centers, resulting in short argentophilic contacts [Ag1···Ag1 = 3.0199(4) Å and Ag2···Ag2 = 2.9894(4) Å ]. Symmetry equivalent dimers of 2 are connected by N-H···O hydrogen bonds into chains, which are further linked by aromatic π(py)···π(py) stacking interactions into sheets.

Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von cis- und trans-[ReCl4 (NCSe)(SeCN)]2- / Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of cis- and trans-[ReCl4 (NCSe)(SeCN)]2-

1999 ◽  
Vol 54 (3) ◽  
pp. 357-362 ◽  
Author(s):  
S. Strueß ◽  
W. Preetz
Keyword(s):  
Low Temperature ◽  
Crystal Structures ◽  
Normal Coordinate Analysis ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Normal Coordinate ◽  
Space Group ◽  
X Ray ◽  
Cis And Trans ◽  
Ir And Raman

The crystal structures of cis-(n-Bu4N)2[ReCl4(NCSe)(SeCN)] (monoclinic, space group P21/n a = 10.794(3), b = 11.687(3), c = 35.716(4) Å, β = 96.97(1)°, Z = 4) and trans- (CH2Py2)[ReCl4(NCSe)(SeCN)] (monoclinic, space group P21/c, a = 8.348(2), b = 7.518(1), c - 31.295(7) Å, ß = 97.12(2)°, Z = 4) have been determined by single crystal X-ray diffraction analysis. Based on the molecular parameters of the X-ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu4N) salts have been assigned by normal coordinate analysis. The valence force constants are fd(ReN) = 1.68 and fd(ReSe) =1.15 mdyn/Å.

Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von cis-(n-Bu4N)2[ReBr4(NCS)(SCN)], trans-(n-Bu4N)2[ReBr4(NCS)(SCN)] und trans-(n-Bu4N)2[ReBr4(NCSe)(SeCN)]

1999 ◽  
Vol 54 (8) ◽  
pp. 1009-1014 ◽  
Author(s):  
L. Homolya ◽  
W. Preetz
Keyword(s):  
Low Temperature ◽  
Single Crystal ◽  
Diffraction Analysis ◽  
Raman Spectra ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Normal Coordinate ◽  
Space Group ◽  
X Ray ◽  
Ir And Raman

The crystal structures of cis-(n-Bu4N)2[ReBr4(NCS)(SCN)] (1) (monoclinic, space group P21/n, a = 11.203(3), b = 11.738(5), c = 35.218(7) Å, β = 93.434(4)°, Z = 4), trans-(n-Bu4N)2[ReBr4(NCS)(SCN)] (2) (monoclinic, space group P21/n, a = 11.644(7), b = 13.695(3), c = 29.028(8) Å, β = 95.96(4)° Z = 4) and trans-(n-Bu4N)2[ReBr4(NCSe)(SeCN)] (3) (monoclinic, space group P21/n, a = 11.894(2), b = 13.737(2), c = 28.869(7) Å, β = 96.98(10)° Z = 4) have been determined by single crystal X-ray diffraction analysis. Based on these molecular parameters the low temperature (10 K) IR and Raman spectra of the (n-Bu4N) salts have been assigned by normal coordinate analysis. The valence force constants are fd(ReN) = 1.70 (1), 1.75 (2) and 1.75 (3), fd(ReS) = 1.32 (1) and 1.37 (2) and fd(ReSe) = 1.20 mdyn/Å (3).

scholarly journals From space group to space groupoid: the partial symmetry of low-temperature E-vanillyl oxime

2019 ◽  
Vol 75 (4) ◽  
pp. 733-741
Author(s):  
Katharina Ehrmann ◽  
Stefan Baudis ◽  
Berthold Stöger
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
Low Temperature ◽  
Euclidean Space ◽  
Single Crystal ◽  
Connected Components ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Full Symmetry

The phase transition of E-vanillyl oxime {1-[(E)-(hydroxyimino)methyl]-4-hydroxy-3-methoxybenzene, C8H9NO3} has been analysed by single-crystal and powder X-ray diffraction. The high-temperature (HT) phase (P21/a, Z′ = 1) transforms into the low-temperature (LT) phase (threefold superstructure, P\overline{1}, Z′ = 6) at ca 190 K. The point operations lost on cooling, {m [010], 2[010]}, are retained as twin operations and constitute the twin law. The screw rotations and glide reflections are retained in the LT phase as partial operations acting on a subset of Euclidean space {\bb E}^3. The full symmetry of the LT phase, including partial operations, is described by a disconnected space groupoid which is built of three connected components.

Interaction of the methylmercury cation with glycine and alanine: a vibrational and X-ray diffraction study

1986 ◽  
Vol 64 (9) ◽  
pp. 1876-1884 ◽  
Author(s):  
Marie-Claude Corbeil ◽  
André L. Beauchamp ◽  
Serge Alex ◽  
Rodrigue Savoie
Keyword(s):  
Aqueous Solutions ◽  
Diffraction Study ◽  
Raman Spectra ◽  
Infrared Spectra ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Carboxylate Oxygen

The complexes (CH3Hg)Gly, (CH3Hg)(L-Ala), and (CH3Hg)(DL-Ala) were prepared by reacting CH3HgOH with glycine (HGly) and alanine (HAla). Crystals of (CH3Hg)(DL-Ala) are monoclinic, space group P21/c, a = 9.460(2), b = 8.794(2), c = 8.723(2) Å, β = 97.49(2)°, Z = 4. The structure was refined on 935 MoKα reflections to R = 0.042. The complex results from displacement of an alanine NH3+ proton by the CH3Hg+ ion, which is linearly bonded to the —NH2 group. An intramolecular Hg … O contact of 2.63 Å is also formed with a carboxylate oxygen. The Raman and infrared spectra of solid (CH3Hg)Gly and (CH3Hg)(L-Ala) are compared with those of the ligands. Raman spectra of aqueous solutions at different pH indicate that the NH2-bonded structure is retained in solution, although no complexation via the carboxylate occurs.

Synthesis and crystallographic data of a new copper phosphate CuPO4H⋅0.5H2O

2003 ◽  
Vol 18 (1) ◽  
pp. 36-37
Author(s):  
Germa´n Alberto Sierra ◽  
Adriana Echavarria Isaza ◽  
Luz Amparo Palacio ◽  
Carlos Saldarriaga
Keyword(s):  
Thermogravimetric Analysis ◽  
Low Temperature ◽  
Chemical Analysis ◽  
Hydrothermal Method ◽  
Crystallographic Data ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Copper Phosphate

A new copper phosphate, CuPO4H⋅0.5H2O, was synthesized using a low temperature hydrothermal method and characterized by powder X-ray diffraction, thermogravimetric analysis, and chemical analysis. The material is monoclinic, space group P21/c, with a=10.6524(2), b=8.4730(2), c=9.2204(2), β=92.43(0), and V=831.47 Å3.

New mixed-valent alkali chain sulfido ferrates A1+x[FeS2] (A = K, Rb, Cs; x = 0.333–0.787)

2020 ◽  
Vol 235 (8-9) ◽  
pp. 275-290
Author(s):  
Michael Schwarz ◽  
Pirmin Stüble ◽  
Katharina Köhler ◽  
Caroline Röhr
Keyword(s):  
Alkali Metal ◽  
General Structure ◽  
Variable Number ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Modulated Structure ◽  
Space Group ◽  
X Ray ◽  
Local Coordination ◽  
Natural Pyrite

AbstractFour new mixed-valent chain alkali metal (A) sulfido ferrates of the general structure family ${A}_{1+x}\left[{\text{Fe}}_{x}^{\text{II}}{\text{Fe}}_{1-x}^{\text{III}}{\text{S}}_{2}\right]$ were synthesized in the form of tiny green-metallic needles from nearly stoichiometric melts reacting elemental potassium with natural pyrite (A = K) or previously prepared Rb2S/Cs2S2 with elemental iron and sulfur (A = Rb/Cs). The crystal structures of the compounds were determined by means of single crystal X-ray diffraction: In the (3+1)D modulated structure of K7.15[FeS2]4 (space group Ccce(00σ3)0s0, a = 1363.87(5), b = 2487.23(13), c = 583.47(3) pm, q = 0,0,0.444, R1 = 0.055/0.148, x = 0.787), a position modulation of the two crystallographically different undulated ${}_{\infty }{}^{1}\left[{\text{FeS}}_{4/2}\right]$ tetrahedra chains and the surrounding K cations is associated with an occupation modulation of one of the three potassium sites. In the case of the new monoclinic rubidium ferrate Rb4[FeS2]3 (x = $\frac{1}{3}$; space group P21/c, a = 1640.49(12), b = 1191.94(9), c = 743.33(6) pm, β = 94.759(4)°, Z = 4, R1 = 0.1184) the undulation of the tetrahedra chain is commensurate, the repetition unit consists of six tetrahedra. In the second new Rb ferrate, Rb7[FeS2]5 (x = 0.4; monoclinic, space group C2/c, K7[FeS2]5-type; a = 2833.9(2), b = 1197.36(9), c = 744.63(6) pm, β = 103.233(4)°, Z = 4, R1 = 0.1474) and its isotypic mixed Rb/Cs-analog Rb3.6Cs3.4[FeS2]5 (a = 2843.57(5), b = 1226.47(2), c = 759.890(10) pm, β = 103.7170(9)°, R1 = 0.0376) the chain buckling leads to a further increased repetition unit of 10 tetrahedra. For all mixed-valent ferrates, the Fe–S bond lengths continuously increase with the amount (x) of Fe(II). The buckling of the chains is controlled through the local coordination of the S atoms by the variable number of A cations of different sizes.

Strukturuntersuchungen an Diaryldichalkogeniden: Die Molekülstrukturen von [2,4,6-(CF3)3C6H2S]2,[2,4,6-Me3C6H2Te]2 und [2-Me2N-4,6-(CF3)2C6H2Te]2 / Structural Investigations of Diaryl Dichalcogenides: The Molecular Structures of [2,4,6-(CF3)3C6H2S]2, [2,4,6-Me3C6H2Te]2 and [2-Me2N-4,6-(CF3)2C6H2Te]2

1992 ◽  
Vol 47 (3) ◽  
pp. 305-309 ◽  
Author(s):  
Anja Edelmann ◽  
Sally Brooker ◽  
Norbert Bertel ◽  
Mathias Noltemeyer ◽  
Herbert W. Roesky ◽  
...  
Keyword(s):  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Structural Investigations ◽  
Space Group ◽  
X Ray

Abstract The Molecular Structures of [2,4,6-(CF3)3C6H2S]2 (1) [2,4,6-Me3C6H2Te]2 and [2-Me2N-4,6-(CF3)2C6H2Te]2 (3) have been determined by X-ray diffraction. Crystal data: 1: orthorhombic, space group P212121, Z = 4, a = 822.3(2), b = 1029.2(2), c = 2526.6(5) pm (2343 observed independent reflexions, R = 0.042); 2: orthorhombic, space group Iba 2, Z = 8, a = 1546.5(2), b = 1578.4(2), c = 1483.9(1) pm (2051 observed independent reflexions, R = 0.030); 3: monoclinic, space group P 21/c, Z = 4, a = 1118.7(1), b = 1536.5(2), c = 1492.6(2) pm, β = 98.97(1)° (3033 observed independent reflexions, R = 0.025).

The Crystal and Molecular Structures of Two Modifications of cis-Dichloro-mer-tris-(dimethylphenylphosphine)hydridoiridium(III)

1988 ◽  
Vol 41 (3) ◽  
pp. 283 ◽  
Author(s):  
GB Robertson ◽  
PA Tucker
Keyword(s):  
Heavy Atom ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
Metal Ligand ◽  
Ligand Bond

The structures of two crystalline modifications of mer -(Pme2Ph)3H-cis-Cl2IrIII, (1), have been determined from single-crystal X-ray diffraction data. Modification (A) is monoclinic, space group P21/c with a 12.635(1), b 30.605(3), c 14.992(2)Ǻ, β 110.01(2)° and Z = 8. Modification (B) is orthorhombic, space group Pbca with a 27.646(3), b 11.366(1), c 17.252(2)Ǻ and Z = 8. The structures were solved by conventional heavy atom techniques and refined by full-matrix least- squares analyses to conventional R values of 0.037 [(A), 8845 independent reflections] and 0.028 [(B), 5291 independent reflections]. Important bond lengths [Ǻ] are Ir -P(trans to Cl ) 2.249(1) av. (A) and 2.234(1) (B), Ir -P(trans to PMe2Ph) 2.339(2) av. (A) and 2.344(1), 2.352(1) (B), Ir-Cl (trans to H) 2.492(2), 2.518(2) (A) and 2.503(1) (B) and Ir-Cl (trans to PMe2Ph)2.452(2) av. (A) and 2.449(1)(B). Differences in chemically equivalent metal- ligand bond lengths emphasize the importance of non-bonded contacts in determining those lengths.

scholarly journals Struktur- und Phasenübergangsuntersuchungen an β-Li2ZnGe/ Structure and Phase Transition Investigations on β-Li2ZnGe

1981 ◽  
Vol 36 (8) ◽  
pp. 917-921 ◽  
Author(s):  
Hans-Otto Cullmann ◽  
Heinz-Walter Hinterkeuser ◽  
Hans-Uwe Schuster
Keyword(s):  
Phase Transition ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Single Crystal ◽  
Ternary Compound ◽  
Type Structure ◽  
Crystal Data ◽  
Space Group ◽  
Cell Parameters ◽  
Structure Space

Abstract The ternary compound β-Li2ZnGe was prepared and its structure determined from powder and single crystal data. The compound crystallizes in a modified Na3As type structure, space group Ṗ̇̇̇̇̇̇̇̇̇̇̇̇̇̇3̄m 1 - D33d.The cell parameters are: a = 432.6 pm, c = 1647.0 pm, c/a= 3.83.A phase transition between a-and β-Li2ZnGe was found and the reaction of the elements lithium, zinc and germanium to a-Li2ZnGe was followed by differential thermal analysis. The temperatures and the enthalpies of transition and fusion were determined.

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