Substitutional solid solutions of Cr_2O_3 in Fe_4Mo_3O_(20) with a limited admixture solubility

摘要

Solid solution phases of a formula Fe_(4-x)Cr_xV_2Mo_3O_(20), where x ε (0; 2>, have been obtained, possessing a structure of the compound Fe_4V_2Mo_3O_(20). It was found on the base of XRD and DTA investigations that these solutions melted incongruently, with increasing the value of x, in the temperature range from 1033 to 1073 K depositing solid solutions of the formulae Fe_(2-y)Cr_y(MoO_4)_3 and Fe_(2-z)Cr_zO_3. The increase of the Cr~(3+) ions content in the crystal lattice of Fe_4V_2Mo_3O_(20) causes the lattice contraction, which is evidenced by a decreasing unit cell volume and a shift of IR absorption bands towards higher wave-number values.