Magnetic layered perovskites of [CH3C(NH2)2]2[M(HCOO)4] (M = Co2+ and Ni2+): synthesis, structures and properties12. Issue 34 (3rd July 2018)

• Record Type: Journal Article
• Authors: Liu, Shu; Wang, Bing-Wu; Wang, Zhe-Ming; Gao, Song
• Is Part Of: Dalton transactions. Volume 47:Issue 34(2018)
• Page Start: 11925
• Page End: 11933
• Publication Date: 2018-07-03
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt01729h
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Two layered perovskites of the formula [CH3 C(NH2 )2 ]2 [M(HCOO)4 ] (M = Co and Ni) exhibit anisotropic thermal expansion behavior and weak ferromagnetism. Abstract : We present two layered perovskites of the formula [CH3 C(NH2 )2 ]2 [M(HCOO)4 ] (M = Co and Ni). The two materials are isostructural and crystallize in the orthorhombic space group Pccn . The structures consist of anionic 〈100〉-oriented perovskite or square metal-formate layers and interlayer [CH3 C(NH2 )2 ] + cations. In each layer octahedral M 2+ ions are linked by equatorial anti – anti HCOO − bridges and are further coordinated by apical monodentate HCOO − groups. The interlayer acetamidinium cations form N–H⋯O H-bonds with the anionic layers to support the 3D structure. As the directions of most vibrations of the interlayer atoms are approximately along the a -axis, the two materials exhibit nearly zero thermal expansion (a few (MK) −1 ) along the b -direction perpendicularly to the layers and positive thermal expansion along the a - (∼40 (MK) −1 ) and c - (∼20 (MK) −1 ) axes parallel to the layers. They are both weak ferromagnets, and the Néel temperatures are 6.0 K and 17.0 K for M = Co and Ni, respectively. The Co compound exhibited high spontaneous magnetization of 444 cm 3 G mol −1 under a field of 10 Oe and an unusually low coercive field of 38 Oe at 2 K. IR spectroscopic, thermal and dielectric properties were investigated.