Solvothermal synthesis, phase transition and crystal structure of β- and γ-CuPb3Br7

2005 ◽  
Vol 220 (2/3) ◽  
Author(s):  
Thorsten Oldag ◽  
Hans-Lothar Keller
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Single Crystals ◽  
Solvothermal Synthesis

AbstractSingle crystals of CuPb

scholarly journals Magnetocaloric properties of the single crystal Mn0.99Fe0.01As

2019 ◽  
Vol 55 (1) ◽  
pp. 118-124
Author(s):  
G. A. Govor ◽  
A. O. Larin ◽  
V. I. Mitsiuk ◽  
G. S. Rimskiy ◽  
T. M. Tkachenkа
Keyword(s):  
Magnetic Field ◽  
Crystal Structure ◽  
Phase Transition ◽  
Phase Transitions ◽  
External Magnetic Field ◽  
Single Crystal ◽  
Single Crystals ◽  
Calculation Method ◽  
Magnetostructural Transition ◽  
Magnetocaloric Properties

The Stockbargard – Bridgman method yielded single crystals Mn0.99Fe0.01As. The effect of an external magnetic field with an intensity of up to 10 T on phase transitions in the single crystal Mn0.99Fe0.01As is studied. It is established that the magnetostructural phase transition in Mn0.99Fe0.01As is accompanied by a change in the entropy ΔSm, which is due to the transformation of the crystal structure. At temperatures above the temperature of the magnetostructural transition Tu = 290 K, the existence of an unstable magnetic structure is obtained. The magnetocaloric characteristics of the material under study are determined by an indirect calculation method based on the Maxwell thermodynamic relations and the Clapeyron – Clausius equation.

Crystal structure, elastic properties and ferroelastic phase transition of disodium tetrahydrogen tris(adipate) dihydrate Na2H4(C6H8O43 · 2 H2O

1995 ◽  
Vol 210 (8) ◽  
Author(s):  
L. Wiehl ◽  
X.-Q. Liu ◽  
S. Haussühl
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Thermal Expansion ◽  
Single Crystals ◽  
Elastic Properties ◽  
Elastic Constants ◽  
Ferroelastic Phase Transition

AbstractElastic constants and thermal expansion were measured using large single crystals of monoclinic Na

Synthese, Kristallstruktur und Eigenschaften von 1,1,1,3,3, 3 - Hexaamino - 1λ5,3λ5-diphosphazeniumehlorid [(NH2)3PNP(NH2)3]Cl / Synthesis, Crystal Structure, and Properties of 1,1,1,3,3,3-Hexaamino- 1λ5 ,3λ5-diphosphazenium Chloride [(NH2)3 PNP(NH2)3 ]Cl

1996 ◽  
Vol 51 (12) ◽  
pp. 1732-1738 ◽  
Author(s):  
Stefan Horstmann ◽  
Wolfgang Schnick
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Temperature Gradient ◽  
Single Crystal ◽  
Single Crystals ◽  
Room Temperature ◽  
Acetonitrile Solution ◽  
Structure And Properties ◽  
X Ray ◽  
Ray Methods

[(NH2)3PNP(NH2)3]Cl has been prepared by a three step synthesis. The last step is the ammonolysis of [Cl3PNPCl3]Cl. Single crystals of 1,1,1,3,3,3-hexaamino-1λ5, 3λ5-diphosphazenium chloride were obtained from an acetonitrile solution in a temperature gradient between 60 °C and room temperature. Between room temperature and -100 °C [(NH2)3PNP(NH2)3]Cl is subject to a phase transition. Therefore, the crystal structure was determined by single crystal X-ray methods at room temperature (P1̄, a = 584.7(1) pm, b = 732.1(1) pm, c = 1092.0(2) pm. q = 71.05(3)°, β = 76.36(3)°, γ = 89.83(3)°, Z = 2, R = 4.75 %, wR = 2.47 %). The cation [(NH2)3PNP(NH2)3]+ is built up by two corner sharing PN4 tetrahedra. Remarkably short P-N bonding distances have been observed and both PN4 tetrahedra exhibit a significant distortion resulting in two large and four small N-P-N bond angles.

Ca(SCN)2 and Ca(SCN)2 · 2 H2O: Crystal Structure, Thermal Behavior and Vibrational Spectroscopy

2002 ◽  
Vol 57 (12) ◽  
pp. 1419-1426 ◽  
Author(s):  
Claudia Wickleder ◽  
Patrick Larsen
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Hydrogen Bonding ◽  
Single Crystals ◽  
Three Dimensional ◽  
Water Molecules ◽  
Dimensional Network ◽  
Thermal Investigations ◽  
Unknown Structure ◽  
Ir And Raman

The dehydration of Ca(SCN)2∙4H2O yields single crystals of Ca(SCN)2 ∙ 2 H2O as well as of Ca(SCN)2. Ca(SCN)2 ∙ 2 H2O crystallizes with a hitherto unknown structure (orthorhombic, Pnma, Z = 4, a = 1280.1(2), b = 790.3(1), c = 726.9(1) pm, Rall = 0.0430). The Ca2+ ions are surrounded by four SCN− ions and four water molecules. The polyhedra are connected to chains along [010] via common oxygen atoms. The SCN− ions connect these chains to a three-dimensional network so that each thiocyanate group is linked to two Ca2+ ions. Hydrogen bonding with sulfur atoms as acceptors is observed. The crystal structure of Ca(SCN)2 (monoclinic, C2/c, Z = 4, a = 961.7(2), b = 642.4(2), c = 787.2(2) pm, Rall = 0.0673) consists of alternating layers of Ca2+ and SCN− ions. The cations are surrounded by four sulfur and four nitrogen atoms in form of a square antiprism. According to 3∞[Ca(SCN)8/4] each SCN− ion connects four Ca2+ ions with each other. Thermal investigations show a phase transition of Ca(SCN)2 ∙ 4 H2O followed by dehydration to Ca(SCN)2 which finally decomposes yielding CaS. IR and Raman measurements have been performed and the resulting frequencies assigned and discussed.

Synthesis and Crystal Structure of Mn2(C2H5NH2)2Sb2S5 Exhibiting a Reversible Phase Transition

2001 ◽  
Vol 56 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Michael Schur ◽  
Christian Näther ◽  
Wolfgang Bensch
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Title Compound ◽  
Solvothermal Synthesis ◽  
Building Blocks ◽  
Synthesis And Crystal Structure ◽  
Reversible Phase Transition ◽  
Reversible Phase ◽  
Solvothermal Conditions

Abstract Thioantimonates, Solvothermal Synthesis, Chalcogenides The reaction of elemental manganese, antimony and sulfur with ethylamine under mild solvothermal conditions yielded a thioantimonate(III) with composition Mn2(EA)2Sb2S5 (EA = C2H5NH2) that is a new member of a series of polymeric manganese thioantimo-nates(III). The structure of the title compound consists of layers of a neutral mesh-like Mn2Sb2S5 framework. The ethylamino ligands coordinated to the Mn centres separate the sheets and fill the voids within the layers formed by the interconnection of Mn2Sb2S4 hetero-cubane like building blocks. Below 273 K a reversible phase transition occurs, which is accom­panied by a doubling of the crystallographic a-axis.

scholarly journals Twinned caesium cerium(IV) pentafluoride

2014 ◽  
Vol 70 (3) ◽  
pp. i12-i13 ◽  
Author(s):  
Andrzej Grzechnik ◽  
Christopher C. Underwood ◽  
Joseph W. Kolis
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Single Crystals ◽  
Coordination Numbers

Single-crystals of CsCeF5were synthesized hydrothermally. The crystal under investigation was twinned by pseudo-merohedry with a twofold rotation around thecaxis as an additional twinning operation. The crystal structure is built of layers of distorted edge- and corner-sharing CeF8square-antiprisms. The Cs+cations are located between the layers and exhibit coordination numbers of nine. Upon compression, CsCeF5undergoes an irreversible phase transition at about 1 GPa.

Crystal structure, elastic properties and phase transition of triclinic ammonium hydrogen succinate, NH4HC4H4O4

1993 ◽  
Vol 206 (2) ◽  
Author(s):  
S. Haussühl ◽  
J. Schreuer
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Aqueous Solutions ◽  
Single Crystals ◽  
Elastic Properties ◽  
Structure Analysis ◽  
Optical Quality ◽  
Space Group ◽  
X Ray ◽  
Ammonium Hydrogen

AbstractLarge optical quality, single crystals of triclinic ammonium hydrogen succinate have been grown from aqueous solutions. An X-ray structure analysis yields space group

Crystal Structure and Thermal Behaviour of Er2(SeO4)3 · 8H2O

2004 ◽  
Vol 59 (9) ◽  
pp. 958-962 ◽  
Author(s):  
Ina Krügermann ◽  
Mathias S. Wickleder
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Single Crystals ◽  
Thermal Behaviour ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Monoclinic Space Group ◽  
Powder Diffraction Data ◽  
Temperature Dependent ◽  
Selenic Acid

Single crystals of Er2(SeO4)3 ・ 8H2O were obtained by dissolving Er2O3 in selenic acid. The selenate crystallizes in the monoclinic space group C2/c (Z = 4, a = 1372.8(2), b = 687.51(7), c = 1860.2(3) pm, β = 101.85(2)◦, Rall = 0.0518) and contains the Er3+ ions in eightfold coordination of oxygen atoms that belong to two crystallographically different SeO42− ions and to four H2O molecules. According to DTA/TG measurements and temperature dependent powder diffraction data, Er2(SeO4)3 ・8H2O decomposes in several steps yielding finally Er2O3. Er2(SeO4)3 and Er2(SeO3)3 could be identified as intermediates, and for Er2(SeO4)3 a phase transition was detected.

Dynamic low-dose electron diffraction and imaging of phase transitions in polymers

1993 ◽  
Vol 51 ◽  
pp. 890-891
Author(s):  
David C. Martin ◽  
Jun Liao
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Electron Diffraction ◽  
Low Dose ◽  
Dark Field ◽  
Continuous Change ◽  
Selected Area Electron Diffraction ◽  
Resolution Electron ◽  
Chain Axis ◽  
High Resolution Electron Micrographs

By careful control of the electron beam it is possible to simultaneously induce and observe the phase transformation from monomer to polymer in certain solid-state polymcrizable diacetylenes. The continuous change in the crystal structure from DCHD diacetylene monomer (a=1.76 nm, b=1.36 nm, c=0.455 nm, γ=94 degrees, P2l/c) to polymer (a=1.74 nm, b=1.29 nm, c=0.49 nm, γ=108 degrees, P2l/c) occurs at a characteristic dose (10−4C/cm2) which is five orders of magnitude smaller than the critical end point dose (20 C/cm2). Previously we discussed the progress of this phase transition primarily as observed down the [001] zone (the chain axis direction). Here we report on the associated changes of the dark field (DF) images and selected area electron diffraction (SAED) patterns of the crystals as observed from the side (i.e., in the [hk0] zones).High resolution electron micrographs (HREM), DF images, and SAED patterns were obtained on a JEOL 4000 EX HREM operating at 400 kV.

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