Samarium(III) molybdate

Samarium(III) molybdate is an inorganic compound, with the chemical formula Sm2(MoO4)3. It is one of the compounds formed by the three elements samarium, molybdenum and oxygen.

Preparation
Samarium(III) molybdate can be obtained by reacting samarium(III) nitrate and sodium molybdate in the pH range of 5.5~6.0. Its single crystal can be grown at 1085 °C by the Czochralski method.

Samarium(III) molybdate can also be prepared by reacting samarium and molybdenum(VI) oxide:
 * $$\mathsf{ Sm_2O_3 + 3MoO_3 \ \xrightarrow{800^oC}\ Sm_2(MoO_4)_3 }$$

Properties
Samarium(III) molybdate forms violet crystals of several modifications:
 * orthorhombic crystal system, space group P ba2, unit cell parameters a = 1.04393 nm, b = 1.04794 nm, c = 1.07734 nm, Z = 4, exists at temperatures below 193°C.
 * monoclinic crystal system, exists at temperatures above 193°C.

Samarium(III) molybdate exhibits ferroelectric properties. It forms a crystalline hydrate with the composition Sm2(MoO4)3•2H2O.

Samarium(III) molybdate can be reduced to the tetravalent molybdenum compound Sm2Mo3O9 by hydrogen at 500~650 °C.