Crystal structure and optical and magnetic properties of Pr(2)(MoO(4))(3)

Inorg Chem. 2010 Feb 15;49(4):1587-94. doi: 10.1021/ic9019876.

Abstract

Praseodymium molybdate Pr(2)(MoO(4))(3) was synthesized using the standard ceramic route. The crystal structure of the material has been successfully solved in superspace group I2/b(alphabeta0)00 with lattice constants a = 5.30284(4), b = 5.32699(3), c = 11.7935(1) A, gamma = 90.163(1) degrees , and the modulation vector q = 2/3a* + 0.88810(2)b*. The deviation of the q vector from a rational value allows a description of the structure in terms of nanosize domains with the La(2)(MoO(4))(3)-like structure separated by stacking faults. Under 450 nm excitation, ((3)P(0) level) Pr(2)(MoO(4))(3) exhibits the characteristic red emission, with the most intense band at 649 nm corresponding to a (3)P(0) --> (3)F(2) transition. Magnetic susceptibility measurements reveal Curie-Weiss paramagnetism with predominating antiferromagnetic interactions between Pr(3+)-magnetic moments and no evidence of magnetic transitions down to T = 5 K.