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La1-xCaxCrO3 (x = 0.0-0.5) samples were prepared by the sol-gel method. The sintering temperature of the samples can decrease to 1573 K. The crystal structures of La1-xCaxCrO3 at room temperature all are of the orthorhombic perovskite GdFeO3-type. XPS analysis indicates that the chromium ions are in a mixed valence state. The introduction of Ca2+ into the lattice is compensated by the oxidation of Cr3+ to Cr6+. With increasing x, the amount of Cr6+ increases. The presence of Cr6+ is one of the key factors affecting the electrical conductivity of La1-xCaxCrO3. (C) 2001 Published by Elsevier Science Ltd.