Thermal expansion and structure of orthorhombic CaMnO3

The structure of CaMnO3 has been studied frond room temperature to 800 degrees C by high-resolution synchrotron X-ray powder diffraction. It is concluded that CaMnO3 remains orthorhombic in Pbnm over the entire temperature range, with the expansion in the cell volume well fitted to the expression Vol = 207.37(2) + 0.00563(8)T + 1.17(9) x 10(-6)T(2). The magnitude of the MnO6 tilts is estimated from the refined structural parameters and these progressively reduce as the temperate is increased. (c) 2006 Elsevier Ltd. All rights reserved.