scholarly journals Temperature-dependent structures of proton-conducting Ba(Zr0.8−xCexY0.2)O2.9ceramics by Raman scattering and x-ray diffraction

2012 ◽  
Vol 24 (15) ◽  
pp. 155403 ◽  
Author(s):  
C-S Tu ◽  
R R Chien ◽  
V H Schmidt ◽  
S C Lee ◽  
C-C Huang
1994 ◽  
Vol 49 (12) ◽  
pp. 1119-1130
Author(s):  
Toshiyuki Takamuku ◽  
Keisuke Nakamura ◽  
Mikito Ihara ◽  
Toshio Yamaguchi

Abstract The structure of zinc(II) bromo complexes in methanol and N,N-dimethylformamide (DMF) (molar ratio [solvent]/[ZnBr2] = 10, temperature range 77 -333 K) has been investigated by Raman scattering and X-ray diffraction. In the methanol solution symmetric Zn - Br vibrations (γ1) of the dibromo- and tribromozinc(II) complexes were observed at 209 and 184 cm-1, respectively. With decreasing temperature the intensity of the γ1 band decreased for the dibromo and increased for the tribromo complex. In addition, the γ1 band for the tetrabromo complex appeared in the supercooled and glassy methanol solutions. In the DMF solution only one band, assigned to both the dibromo-and tribromozinc(II) complexes, was observed. Its intensity did not change with temper­ature. The X-ray diffraction data revealed that the average number of Zn -Br interactions within the zinc (II) bromo complexes does not change with temperature while the number of nonbonding Br ··· Br interactions within the complexes increases from 1.5 at 298 K to 1.9 at 243 K for the methanol solution and from 1.3 at 298 K to 1.8 at 243 K for the DMF solution. These Raman and X-ray results have confirmed that in both methanol and DMF solutions at high temperatures the dibromo species is predominantly formed, whereas at low temperatures the tribromo complex is favored, the tetrabromo species being formed only in the supercooled and glassy methanol solutions. The temperature dependent equilibrium shifts of the zinc(II) bromo complexes in the methanol and DMF solutions are discussed together with previously reported results for the aqueous phase.


Author(s):  
Simon Engelbert ◽  
Rolf-Dieter Hoffmann ◽  
Jutta Kösters ◽  
Steffen Klenner ◽  
Rainer Pöttgen

Abstract The structures of the equiatomic stannides RERhSn with the smaller rare earth elements Y, Gd-Tm and Lu were reinvestigated on the basis of temperature-dependent single crystal X-ray diffraction data. GdRhSn crystallizes with the aristotype ZrNiAl at 293 and 90 K. For RE = Y, Tb, Ho and Er the HP-CeRuSn type (approximant with space group R3m) is already formed at room temperature, while DyRhSn adopts the HP-CeRuSn type below 280 K. TmRhSn and LuRhSn show incommensurate modulated variants with superspace groups P31m(1/3; 1/3; γ) 000 (No. 157.1.23.1) (γ = 3/8 for TmRhSn and γ = 2/5 for LuRhSn). The driving force for superstructure formation (modulation) is a strengthening of Rh–Sn bonding. The modulation is expressed in a 119Sn Mössbauer spectrum of DyRhSn at 78 K through line broadening.


2013 ◽  
Vol 68 (9) ◽  
pp. 971-978 ◽  
Author(s):  
Inga Schellenberg ◽  
Ute Ch. Rodewald ◽  
Christian Schwickert ◽  
Matthias Eul ◽  
Rainer Pöttgen

The ternary antimonides RE4T7Sb6 (RE=Gd-Lu; T =Ru, Rh) have been synthesized from the elements by arc-melting and subsequent annealing in an induction furnace. The samples have been characterized by powder X-ray diffraction. Four structures were refined on the basis of single-crystal X-ray diffractometer data: U4Re7Si6 type, space group Im3m with a=862.9(2) pm, wR2=0.0296, 163 F2 values for Er4Ru7Sb6; a=864.1(1) pm, wR2=0.1423, 153 F2 values for Yb4Ru7Sb6; a=872.0(2) pm, wR2=0.0427, 172 F2 values for Tb4Rh7Sb6; and a=868.0(2) pm, wR2=0.0529, 154 F2 values for Er4Rh7Sb6, with 10 variables per refinement. The structures have T1@Sb6 octahedra and slightly distorted RE@T26Sb6 cuboctahedra as building units. The distorted cuboctahedra are condensed via all trapezoidal faces, and this network leaves octahedral voids for the T1 atoms. The ruthenium-based series of compounds was studied by temperature-dependent magnetic susceptibility measurements. Lu4Ru7Sb6 is Pauli-paramagnetic. The antimonides RE4Ru7Sb6 with RE=Dy, Ho, Er, and Tm show Curie-Weiss paramagnetism. Antiferromagnetic ordering occurs at 10.0(5), 5.1(5) and 4.0(5) K for Dy4Ru7Sb6, Ho4Ru7Sb6 and Er4Ru7Sb6, respectively, while Tm4Ru7Sb6 remains paramagnetic. Yb4Ru7Sb6 is an intermediate-valent compound with a reduced magnetic moment of 3.71(1) μB per Yb as compared to 4.54 μB for a free Yb3+ ion


CrystEngComm ◽  
2011 ◽  
Vol 13 (1) ◽  
pp. 312-318 ◽  
Author(s):  
Navneet Soin ◽  
Susanta Sinha Roy ◽  
Christopher O'Kane ◽  
James A. D. McLaughlin ◽  
Teck H. Lim ◽  
...  

1996 ◽  
Vol 52 (a1) ◽  
pp. C535-C535
Author(s):  
E. Wolanin ◽  
Ph. Pruzan ◽  
M. Gauthier ◽  
J. C. Chervin ◽  
B. Canny ◽  
...  

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