Effet Jahn-Teller coopératif dans le systéme Mn3O4Mn2SnO4
Review articleOpen access
Marc Nogués - No affiliation found
1974/04/01 Full-length article DOI: 10.1016/0022-4596(74)90091-7
Journal: Journal of Solid State Chemistry
AbstractMn3+ ion (3d4, t32geg1) is liable to induce, by a cooperative Jahn-Teller effect, a macroscopic distortion of the cubic spinel structure; it is so in haussmanite Mn3O4, a tetragonal structure. The effect of chemical composition on “tetragonal-cubic” spinel transformations in the system Mn3O4Mn2SnO4 has been studied by X-ray diffraction; the c and a′ unit-cell dimensions show an abrupt change at a critical composition beyond which the system has the cubic spinel structure. The cation distribution has been worked out from an analysis of the X-ray diffraction intensities, and a correlation between the number of Mn3+ ions in octahedral sites and the degree of distortion has been obtained; the values of “cation-anion” bond distances, in six coordination, show that, in this system, the oxygen octahedral distortion and the macroscopic cell distortion are in a direct relationship. The paramagnetic study always attributes the “high-spin” configuration t32geg1 to manganese.
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