The state of cerium atoms in solid solutions Y_0.9Ce_0.1CaCr_xAl_1-xO₄ and Y_0.8Ce_0.1Ca_1.1Cr_x· Al_1-xO₄ (0 ≤ x ≤ 0.1) was studied by crystal chemistry and magnetochemistry methods. The atomic coordinates and interatomic distances were calculated. Solid solutions Y_0.9Ce_0.1CaCr_xAl_1-xO₄ contain cerium in the reduced state Ce(III), whereas Y_0.8Ce_0.1Ca_1.1Cr_xAl_1-xO ₄ solutions contain Ce(IV).