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

Abstract

Abstract The perovskite-related cyano compounds CsM II Cr(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.