Nonstoichiometry and reductive decomposition of CaMnO3-δ

被引：85

作者：

Bakken, E ^{[1
]}

Norby, T ^{[1
]}

Stolen, S ^{[1
]}

机构：

[1] Univ Oslo, Dept Chem, N-0315 Oslo, Norway

来源：

SOLID STATE IONICS | 2005年 / 176卷 / 1-2期

关键词：

CaMnO3-delta; non-stoichiometry; stability; redox energetics;

D O I：

10.1016/j.ssi.2004.07.001

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The variation of the oxygen stoichiometry of CaMnO3-delta with the partial pressure of oxygen has been measured by coulometric titration at 1223, 1273 and 1373 K, and the technique used is described in some detail. CaMnO3-delta is not stable under reducing conditions; at 1273 K, CaMnO3-delta decomposes at log(Po-2/Po(2)degrees)=-1.8 with (3-delta)congruent to 2.84, under the formation of Ca2MnO4-delta and CaMn2O4. The partial molar enthalpy and entropy of oxidation of CaMnO3-delta are derived for 2.92>(3-delta)>2.86. The obtained partial molar enthalpy of oxidation is constant (H-o-H(o)degrees=-163.5 +/- 7.5 kJ mol(-1)) within the estimated uncertainty (twice the standard deviation of the mean), whereas the partial molar entropy of oxidation appears to vary with the oxygen stoichiometry. (C) 2004 Elsevier B.V. All rights reserved.

引用

页码：217 / 223

页数：7

共 22 条

[1] Redox energetics of SrFeO3-δ -: a coulometric titration study [J].