Original scientific paper

Crystal Growth and Unusual Electronic Transport Properties of Some Reduced Molybdenum Oxides with Bi-Octahedral Mo₁₀ Clusters

Phillipe Gall ; Université de Rennes 1. Laboratoire de Chimie du Solide et Inorganique Molèculaire, URA CNRS No. 1495, Av. du Général Leclerc, 35042 Rennes CEDEX, France
Patrick Gougeon ; Université de Rennes 1. Laboratoire de Chimie du Solide et Inorganique Molèculaire, URA CNRS No. 1495, Av. du Général Leclerc, 35042 Rennes CEDEX, France
Martha Greenblatt ; Department of Chemistry, Rutgers University, Piscataway, NJ 08855, USA
Berry B. Jones ; Department of Chemistry, Rutgers University, Piscataway, NJ 08855, USA
William H. McCarroll ; Department of Chemistry, Rider College, Lawrenceville, NJ 08648, USA
Kandalam V. Ramanujachary ; Department of Chemistry, Rider College, Lawrenceville, NJ 08648, USA

Abstract

Single crystals of AM05O3 (A = Ca, Sr, La-Gd), suitable for electrical conductivity measurements have been grown by high temperature and fused salt electrolytic techniques. The structures of all of these compounds are dominated by the presence of bi-octahedral clusters of Mo atoms joined together parallel to the monoclinic a axis, forming infinite chains. Temperature dependent electrical resistivity measurements on AMo5Og (A = La, Ce, Pr, Nd, Sm) show anomalous metal-semiconductor transitions near 180 and 30 K.
The resistivities of the Eu and Gd analogues are different, in that the former is semiconducting while the latter shows a weak anomaly ~ 110 K. The Ca and Sr analogues are also semiconducting in the range 20-300 K. The electrical conductivity of these phases appears to be closely related to the inter-cluster separation and the number of metal-cluster electrons. The magnetic susceptibility of these compounds show no anomalies at the temperatures corresponding to the transitions seen in their electrical resistivities. The magnetic susceptibility of LaMosOg shows a small decrease in the \!y (dy/dT) vs T plot in the vicinity of ~ 150 K.

Keywords

Hrčak ID:

136697

URI

https://hrcak.srce.hr/136697

Publication date:

1.11.1995.

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