The High-temperature Modification of LuAgSn and High-pressure High-temperature Experiments on DyAgSn, HoAgSn, and YbAgSn

2008 ◽  
Vol 63 (2) ◽  
pp. 193-198 ◽  
Author(s):  
Birgit Heying ◽  
Ute Ch. Rodewald ◽  
Gunter Heymann ◽  
Wilfried Hermes ◽  
Falko M. Schappacher ◽  
...  

The high-temperature modification of LuAgSn was obtained by arc-melting an equiatomic mixture of the elements followed by quenching the melt on a water-cooled copper crucible. HT-LuAgSn crystallizes with the NdPtSb-type structure, space group P63mc: a = 463.5(1), c = 723.2(1) pm, wR2 = 0.0270, 151 F2, and 11 variables. The silver and tin atoms build up two-dimensional, puckered [Ag3Sn3] networks (276 pm Ag-Sn) that are charge-balanced and separated by the lutetium atoms. The Ag-Sn distances between the [Ag3Sn3] layers of 294 pm are much longer. Single crystals of isotypic DyAgSn (a = 468.3(1), c = 734.4(1) pm, wR2 = 0.0343, 411 F2, and 11 variables) and HoAgSn (a = 467.2(1), c = 731.7(2) pm, wR2 = 0.0318, 330 F2, and 11 variables) were obtained from arc-melted samples. Under high-pressure (up to 12.2 GPa) and high-temperature (up to 1470 K) conditions, no transitions to a ZrNiAl-related phase have been observed for DyAgSn, HoAgSn, and YbAgSn. HT-TmAgSn shows Curie-Weiss paramagnetism with μeff = 7.53(1) μB/Tm atom and θP = −15.0(5) K. No magnetic ordering was evident down to 3 K. HT-LuAgSn is a Pauli paramagnet. Room-temperature 119Sn Mössbauer spectra of HT-TmAgSn and HT-LuAgSn show singlet resonances with isomer shifts of 1.78(1) and 1.72(1) mm/s, respectively

2012 ◽  
Vol 68 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Denis Orosel ◽  
Robert E. Dinnebier ◽  
Vladislav A. Blatov ◽  
Martin Jansen

A quenchable new high-pressure–high-temperature modification of antimony(III) oxide, γ-Sb2O3, has been obtained at hydrostatic pressures of 9–11 GPa and temperatures of 573–773 K. Its crystal structure has been determined from high-resolution synchrotron powder diffraction data. γ-Sb2O3 consists of three-dimensionally cross-linked infinite chains of SbO3 E units (E = lone pair) with the chains forming tetragonal rod-packing. The underlying topology of γ-Sb2O3 (3,3T8) is found very rarely in inorganic structures; it is realised only for the polyanion [Si4O4N6]10− that occurs in the Ce4(Si4O4N6)O structure type. The structural relation to the two previously known polymorphs of Sb2O3 at ambient pressure, valentinite and senarmontite is discussed.


ChemInform ◽  
2008 ◽  
Vol 39 (16) ◽  
Author(s):  
Birgit Heying ◽  
Ute Ch. Rodewald ◽  
Gunter Heymann ◽  
Wilfried Hermes ◽  
Falko M. Schappacher ◽  
...  

2006 ◽  
Vol 47 ◽  
pp. 31-36
Author(s):  
Alberto Ubaldini ◽  
V.P.S. Awana ◽  
S. Balamurugan ◽  
E. Takayama-Muromachi

The ruthenocuprates family is a very interesting class of materials, because of the coexistence of superconductivity and magnetic ordering. Ruthenocuprates include RuSr2RECu2O8 and RuSr2(RE,Ce)2Cu2O10- (RE = rare earth elements or Y). It is possible to synthesize samples of these phases with Gd, Eu or Sm with normal synthesis conditions. For the others high-pressure high-temperature (HPHT) synthesis is required. We had successfully synthesized the RuSr2Tb1.5Ce0.5Cu2O10 by HPHT technique, starting from RuO2, SrO2, Tb4O7, CeO2, CuO and Cu. Around 300 mg of the mixture was allowed to react in a flat-belt-typehigh- pressure apparatus at 6GPa and 1200 °C – 1550 °C. The optimised temperature of synthesis was found to be in the range between 1350 °C – 1450 °C. The as-synthesized compound crystallized with a structure belonging to the space group I4/mmm. DC magnetic susceptibility versus temperature plot for RuSr2Tb1.5Ce0.5Cu2O10 in an applied field of 10 Oe demonstrated magnetic transition at 150 K but the superconducting transition was not clearly observed. To our knowledge this is the first successful synthesis of the Tb based Ru-1222 phase.


2017 ◽  
Vol 72 (12) ◽  
pp. 967-975 ◽  
Author(s):  
Martin K. Schmitt ◽  
Hubert Huppertz

AbstractNi6B22O39·H2O was synthesized in a high-pressure/high-temperature reaction at 5 GPa/900°C. It crystallizes in the orthorhombic space group Pmn21 (no. 31) with the lattice parameters a=7.664(2), b=8.121(2) and c=17.402(2) Å. The crystal structure is discussed with regard to the isotypic compounds M6B22O39·H2O (M=Fe, Co) and the structurally related phase Cd6B22O39·H2O. Furthermore, the characterization of Ni6B22O39·H2O via X-ray powder diffraction and vibrational spectroscopy is reported.


2017 ◽  
Vol 72 (1) ◽  
pp. 77-82 ◽  
Author(s):  
Gunter Heymann ◽  
Birgit Heying ◽  
Ute Ch. Rodewald ◽  
Oliver Janka

AbstractThe intermetallic aluminum compound HP-CePtAl was synthesized by arc melting of the elements with subsequent high-pressure/high-temperature treatment at 1620 K and 10.5 GPa in a multianvil press. The compound crystallizes in the hexagonal MgZn2-type structure (P63/mmc) with lattice parameters of a=552.7(1) and c=898.8(2) pm refined from powder X-ray diffraction data. With the help of single crystal investigations (wR=0.0527, 187 F2 values, 13 variables), the proposed structure type was confirmed and the mixed Pt/Al site occupations could be refined. Magnetic susceptibility measurements showed a disappearance of the complex magnetic ordering phenomena, which are observed in NP-CePtAl.


2015 ◽  
Vol 70 (4) ◽  
pp. 207-214 ◽  
Author(s):  
Daniela Vitzthum ◽  
Stefanie A. Hering ◽  
Lukas Perfler ◽  
Hubert Huppertz

AbstractOrthorhombic dysprosium orthogallate DyGaO3 and trigonal gallium orthoborate GaBO3 were synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 8.5 GPa/1350 °C and 8 GPa/700 °C, respectively. Both crystal structures could be determined by single-crystal X-ray diffraction data collected at room temperature. The orthorhombic dysprosium orthogallate crystallizes in the space group Pnma (Z = 4) with the parameters a = 552.6(2), b = 754.5(2), c = 527.7(2) pm, V = 0.22002(8) nm3, R1 = 0.0309, and wR2 = 0.0662 (all data) and the trigonal compound GaBO3 in the space group R3̅c (Z = 6) with the parameters a = 457.10(6), c = 1419.2(3) pm, V = 0.25681(7) nm3, R1 = 0.0147, and wR2 = 0.0356 (all data).


1977 ◽  
Vol 32 (4) ◽  
pp. 373-379 ◽  
Author(s):  
Bernt Krebs ◽  
Jürgen Mandt

The room temperature modification of Ag8SiS6 is orthorhombic, space group Pna21, with α = 15.024, b = 7.428, c = 10.533 Å, Z = 4. A complete single crystal X-ray structure analysis shows the structure to contain tetrahedral SiS4(4-) units (Si-S 2.094(12) ... 2.130(12) Å) besides isolated sulfide groups coordinated by Ag; the compound may thus be formulated as Ag8(SiS4)(S)2. The coordination of the Ag atoms by sulfur is distorted tetrahedral (Ag-S 2.557...2.757 A), approximately trigonal planar (Ag-S 2.386...2.775 A, with one additional weakly bonded axial S at 2.991 ... 3.330 Å), or linear (Ag-S 2.414... 2.443 Å). Within the (ordered) Ag sublattice the temperature factors are significantly higher than for Si and S, indicating a certain mobility of the Ag atoms. The arrangement of the thiosilicate -sulfide part of the structure is pseudocubic face-centered, showing the close structural relationship to the disordered cubic high temperature modification of Ag8GeTe6.


2010 ◽  
Vol 65 (10) ◽  
pp. 1206-1212 ◽  
Author(s):  
Almut Haberer ◽  
Reinhard Kaindl ◽  
Hubert Huppertz

The praseodymium orthoborate λ -PrBO3 was synthesized from Pr6O11, B2O3, and PrF3 under high-pressure / high-temperature conditions of 3 GPa and 800 °C in a Walker-type multianvil apparatus. The crystal structure was determined on the basis of single-crystal X-ray diffraction data, collected at room temperature. The title compound crystallizes in the orthorhombic aragonite-type structure, space group Pnma, with the lattice parameters a = 577.1(2), b = 506.7(2), c = 813.3(2) pm, and V = 0.2378(2) nm3, with R1 = 0.0400 and wR2 = 0.0495 (all data). Within the trigonal-planar BO3 groups, the average B-O distance is 137.2 pm. The praseodymium atoms are ninefold coordinated by oxygen atoms.


2011 ◽  
Vol 66 (2) ◽  
pp. 107-114 ◽  
Author(s):  
Stephanie C. Neumair ◽  
Johanna S. Knyrim ◽  
Oliver Oeckler ◽  
Reinhard Kaindl ◽  
Hubert Huppertz

The cubic iron hydroxy boracite Fe3B7O13OH・1.5H2O was synthesized from Fe2O3 and B2O3 under high-pressure/high-temperature conditions of 3 GPa and 960 °C in a modified Walker-type multianvil apparatus. The crystal structure was determined at room temperature by X-ray diffraction on single crystals. It crystallizes in the cubic space group F4̄3c (Z = 8) with the parameters a = 1222.4(2) pm, V = 1.826(4) nm3, R1 = 0.0362, and wR2 = 0.0726 (all data). The B-O network is similar to that of other cubic boracites.


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