Röntgenograpliische und magnetische Untersuchungen an perowskitverwandten Cyanoverbindungen CsMIIMIII(CN)6 / X-Ray and Magnetic Studies of Perovskite-Related Cyano Compounds CsMIIMIII (CN)6

Abstract

The perovskite-related cyano compounds CsM^IICr(CN)₆ (M^II = Mn, Zn), CsZnFe(CN)₆ and CsMnCo(CN)₆ (Mn = Mn-Cu) are characterized by their IR active C - N and M^III-CN stretching frequencies, their lattice constants and their magnetic susceptibilities (4,2-295 K). Except for CsCuCo(CN)₆, which is tetragonally distorted, all compounds crystallize cubically face-centered (with lattice constants in the range from 1020 to 1084 pm). The magnetic behaviour indicates low spin M^III and high spin M^II states, supporting the IR evidence for a strictly ordered M^III-CN-M^II arrangement. The compound CsMnCr(CN)₆ is ferrimagnetic, with a Néel temperature of T_N = 90 K and an extrapolated spontaneous magnetization of a = 2,30 μ_B at 0 K. Superexchange interactions via the cyano bridges are considered responsible for the ferrimagnetism observed.