Samples of Mg-Mn olivines (MgxMn2-xSiO4) have been prepared at different temperatures (800 °C, 1000 °C and 1300 °C) and with different stoichiometries (x = 0.4, 0.8, 1.0 and 1.4). Synchrotron X-ray powder diffraction data have been collected on Daresbury SRS station 2.3 on these samples. The Rietveld method has been used to refine the orthorhombic (Pnma) olivine structures in order to determine the occupancies of Mg and Mn on the M1 (4a) and M2 (4c) sites, Mn tends to become ordered onto the M2 site. An ordering parameter for each sample is determined from the M1 and M2 site occupancies. The variation of ordering with stoichiometry and preparation temperature is discussed, the degree of order increases with decreasing equilibration temperature.
|Number of pages||4|
|Journal||Materials Science Forum|
|Issue number||pt 2|
|Publication status||Published - 1994|