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Electrical Properties and Dilatometric Measurements of La 2 Mo 2 O 9 under Low Oxygen Partial Pressure
Author(s) -
Tian Xia,
JiaYan Li,
Xin Luo,
Qin Li,
Jian Meng,
XueQiang Cao
Publication year - 2005
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200590703
Subject(s) - chemistry , seebeck coefficient , partial pressure , electrical resistivity and conductivity , oxygen , thermal conduction , ionic bonding , thermal expansion , polaron , thermoelectric effect , lanthanum , ionic conductivity , analytical chemistry (journal) , phase (matter) , phase transition , thermodynamics , condensed matter physics , electrode , inorganic chemistry , electrical engineering , ion , physics , organic chemistry , quantum mechanics , chromatography , electrolyte , engineering , electron
The electrical conductivity and thermal expansion of La 2 Mo 2 O 9 under low oxygen partial pressure were studied with the help of thermoelectric power and dilatometric measurements, respectively. The ionic conduction of La 2 Mo 2 O 9 was predominant with the electronic transference number less than 0.05 above an oxygen partial pressure of about p O 2=10 ‐7 Pa at 700°C, and below this pressure the electronic conduction became obvious. The defect reaction and small polaron hopping among molybdenum sites were proposed to explain the electronic conduction. Accompanying the phase transition, there was a sharp increase of thermal expansion, which became more serious under low oxygen partial pressure. The substitution of lanthanum by neodymium led to the increase of electrical conductivity but the decrease of phase stability.