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1Author    Peter Remmert, Edmund Fischer, Hans-Ulrich HummelRequires cookie*
 Title    Phasenuntersuchungen im System 2 H a -T a S 2-2 H c -M o S 2 Investigations on Phases in the System 2 H a -T a S 2-2 H c -M o S 2  
 Abstract    Ternary phases in the system TaS2-M o S 2 have been obtained by thermal reactions at 1050 °C of binary layered disulfides and N H 4C1 as promotor. Ternary phases Taj_*Mo*S2 exist in the range 0.5 < jc< 0.9. In the range of 0.25 < * < 0.55 the reactions are quantitative and the phase-compositions are determined by the amounts of the starting materials. For x < 0 .2 lT -T a S 2 and for jc> 0.60 2 H c -M o S 2 are contaminating the resulting ternary phases. Ternary phases have been characterized by X-ray powder diffraction and are indexed rhombohedrally on the basis o f a 3 R-structure with metals in trigonal-prismatic coordination. The phases Tal jcMo*S2 with 0.25 < * < 0.55 show a reversible transition of higher order asso­ ciated with a change in the electrical conductivity mechanism. B elow 420 K the phases show semiconductivity while above 460 K metallic conductivity is observed. 
  Reference    Z. Naturforsch. 49b, 1175—1178 (1994); eingegangen am 15. April 1994 
  Published    1994 
  Keywords    Ternary Phases, Preparation, Phase Transition 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-1175.pdf 
 Identifier    ZNB-1994-49b-1175 
 Volume    49 
2Author    M. Arietta, S. Schriewer-Pöttgen, Wolfgang JeitschkoRequires cookie*
 Title    Two Modifications of Hg5Re2O 10  
 Abstract    The previously reported mercury perrhenate Hg5 Re2O 10, prepared hydrothermally, has now been obtained by reaction of HgO with the mercury(II) metaperrhenate H g (R e 0 4)2 in sealed silica tubes. A second modification o f this compound can be obtained by reaction of elem ental mercury with H g (R e 0 4)2 also in sealed silica tubes. Its crystal structure has been determined from single-crystal X-ray data: P 2 x/c, a -861.5(1), b = 1200.9(2), c = 1203.9(2) pm, ß = 97.15(1)°, Z = 4, R = 0.024 for 1733 structure factors and 105 variables. Both modifi­ cations may be represented by the formula H g2+-2H g20 -2 R e 0 4_, indicating that mercury occurs in oxidation states I and II. In both modifications the mercury and some oxygen atoms form two-dimensionally infinte, puckered, cationic nets of the composition (H g2+-2H g20)" , which are separated by the R e 0 4~ tetrahedra. In the modification reported earlier the mer­ cury oxygen nets consist of condensed 16-membered rings, while the nets of the present modification contain 10-and 22-membered rings. 
  Reference    Z. Naturforsch. 50b, 1335—1339 (1995); received February 27 1995 
  Published    1995 
  Keywords    Crystal Structure, Mercury Perrhenates, Phase Transitions 
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 TEI-XML for    default:Reihe_B/50/ZNB-1995-50b-1335.pdf 
 Identifier    ZNB-1995-50b-1335 
 Volume    50 
3Author    Requires cookie*
 Title    Spectroscopic Behaviour of Quasi-One-Dimensional Linear Chains in MgPt(CN)4 * 7 H ,0 Single Crystals  
 Abstract    H a r t m u t Y e r s i n a n d G ü n t e r G l i e m a n n In stitu t In the direction of the crystallographic c-axis MgPt(CN)4 • 7 H 20 has a relatively low P t-P t-distance (3.15 A at 300 °K). Thus the optical behaviour shows inter-molecular interactions. Single crystal polarized emission and absorption spectra were measured between 300 °K and 5 °K. In this tem perature range the emission peaks shift to the red by about 1,100 cm-1. This is attributed to a decrease in Pt-Pt-distance. MgPt(CN)4 • 7 H 20 undergoes phase transitions at about 166 °K and 60 °K. To interprete the solid state emission and absorption behaviour the Davydov theory is applied. The two lowest excited bands of electronic origin are assigned to the symmetries r ^ f k) and r ^ u(k) in the double group Dgh. 
  Reference    (Z. Naturforsch. 30b, 183—190 [1975]; received December 27 1974) 
  Published    1975 
  Keywords    Electronic Spectra, Phase Transitions, Davydov Splitting 
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 TEI-XML for    default:Reihe_B/30/ZNB-1975-30b-0183.pdf 
 Identifier    ZNB-1975-30b-0183 
 Volume    30 
4Author    Otto Cullmann, Heinz-Walter Hinterkeuser, Hans-Uwe SchusterRequires cookie*
 Title    Hans  
 Abstract    The ternary compound /M^ZnGe was prepared and its structure determined from powder and single crystal data. The compound crystallizes in a modified NaßAs type structure, space group PlTm 1-Djjd-The cell parameters are: a = 432.6 pm, c — 1647.0 pm, c/a= 3.83. A phase transition between a-and /S-L^ZnGe 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. Vorbemerkung 
  Reference    Z. Naturforsch. 36b, 917—921 (1981); eingegangen am 20. Mai 1981 
  Published    1981 
  Keywords    Ternary Intermetallic Compounds, Crystal Structure, Phase Transition 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-0917.pdf 
 Identifier    ZNB-1981-36b-0917 
 Volume    36 
5Author    Wolfgang Hönle, Arndt Simon, Gabriele GerlachRequires cookie*
 Title    Darstellung, Kristallstruktur und Eigenschaften von ß-Ga 2 Br 4 Preparation, Crystal Structure and Properties of y3-Ga 2 Br 4  
 Abstract    The compounds Ga 2 Br 4 (a+ß) have been prepared by reacting GaBr 3 with Ga metal without a solvent or in a hydrocarbon medium. a-Ga 2 Br 4 is isotypic with Ga 2 Cl 4 , and /3-Ga 2 Br 4 with Ga 2 I 4 . Both forms have to be formulated as Ga + (GaBr 4)~ according to their crystal structures. The first order phase transition a—*ß has been investigated by means of DTA and temperature dependent X-ray powder photographs. The crystal structure of /3-Ga 2 Br 4 has been refined with single crystal data (R3c; a = 2163.4(8) pm; c = 869.2(4) pm; Z = 18; R = 0.037). Main building units are GaBr 4 " tetrahedra (d(Ga —Br) = 232.9 pm), connected in three dimensions by capped trigonal prisms (6+2+1) around Ga + . The crystal chemical relationships between y3-Ga 2 Br 4 and Ga 2 I 4 are discussed. 
  Reference    Z. Naturforsch. 42b, 546 (1987); eingegangen am 13. November 1986 
  Published    1987 
  Keywords    Phase Transition, DTA Investigation, Crystal Structure 
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 TEI-XML for    default:Reihe_B/42/ZNB-1987-42b-0546.pdf 
 Identifier    ZNB-1987-42b-0546 
 Volume    42 
6Author    H. Einz, Jürgen Beister, K. Arl Syassen, Jürgen KleinRequires cookie*
 Title    Phase Transition of N a3As under Pressure  
 Abstract    We have investigated the high pressure behaviour of N a3As by powder X-ray diffraction. At 3.6 G Pa the material undergoes a reversible phase transition from the N a3As structure (P 6 3/ mmc, a = 487.4(8) pm, c = 851.5(20) pm, Z = 2, at 3.6 G Pa) to the Li3Bi structure type (Fm 3m , a = 683.5(15) pm, Z = 4, at 3.6 GaP). The equation of states is given for the pressure range up to 26 GPa. Results are discussed with respect to structural properties of related A3BV-compounds. 
  Reference    Z. Naturforsch. 45b, 1388—1392 (1990); received M arch 7 1990 
  Published    1990 
  Keywords    High Pressure, Crystal Structure, Phase Transition 
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 TEI-XML for    default:Reihe_B/45/ZNB-1990-45b-1388.pdf 
 Identifier    ZNB-1990-45b-1388 
 Volume    45 
7Author    Marcos Luján, Frank Kubel, Hans SchmidRequires cookie*
 Title    Crystal Growth, Room Temperature Crystal Structure and Phase Transitions of K M nP04  
 Abstract    Single crystals of K M nP 04 grown in a KC1 flux show ferroelastic domains. The structure was determ ined on an optically controlled single domain crystal by X-ray diffraction methods. The cell is triclinic with dimensions a = 5.4813(5), b = 8.627(1), c = 8.887(1), in A, a = 87.73(1)°, ß = 89.10(1)°, y = 88.01(1)°, VM = 419.6(1) A 3 and Z = 4. The structure is closely related to the stuffed /3-tridymite type. DTA experiments between room tem perature and 1000 °C and polarized light microscopy observations showed four phase transitions: at 165, 330, 353 and 707 °C. 
  Reference    Z. Naturforsch. 50b, 1210—1214 (1995); received February 20 1995 
  Published    1995 
  Keywords    Manganese Potassium Orthophosphate, Crystal Structure, Crystal Growth, Phase Transitions 
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 TEI-XML for    default:Reihe_B/50/ZNB-1995-50b-1210.pdf 
 Identifier    ZNB-1995-50b-1210 
 Volume    50 
8Author    Manfred Zabel, Klaus-Jürgen RangeRequires cookie*
 Title    Ternäre Phasen im System Eisen-Thallium-Schwefel Ternary Phases in the System Iron Thallium-Sulfur  
 Abstract    The Compound TlFeS2 was synthesized from TIS/Fe/S-mixtures. Crystals are mono-clinic (space group C2/m) with a = 1164.4(6) pm, b = 530.8(3) pm, c = 1050.9(5) pm, ß = 144.58° and Z = 4. The structure comprises [FeS2 -]oo-chains parallel b, built from edge-shared FeS-i-tetrahedra. Relations between TlFeS2 and orthorhombic CsFeS2 are discussed. Tetragonal or monoclinic distorted tetragonal ternary phases occur with composition FeaTV^ (2.6 <x <3.6). 
  Reference    (Z. Naturforsch. 34b, 1—6 [1979]; eingegangen am 23. August 1978) 
  Published    1979 
  Keywords    System Iron-Thallium-Sulfur, Ternary Compounds, Crystal Structure, Phase Transitions 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-0001.pdf 
 Identifier    ZNB-1979-34b-0001 
 Volume    34