CRYSTAL-STRUCTURE OF LAMNO3+DELTA SYNTHESIZED USING POLY(ACRYLIC ACID)

Poly(acrylic acid) (PAA) was used to make a gel from an aqueous solution of lanthanum and manganese nitrates. In the concentration range 3 × 10-2 to 5 × 10-2M of PAA, the single phase of perovskite-type LaMnO3+δ was synthesized by firing gels at low temperature. The crystal structure of LaMnO3+δ changes from hexagonal to orthohombic with increasing concentration of PAA. At 5 × 10-2M of PAA, the crystal structure of LaMnO3+δ changes from orthorhombic to hexagonal with increasing temperature. © 1993 Academic Press, Inc.