A highly polar hybrid perovskite of [FCH2CH2NH3][Mn(HCOO)3].

A new hybrid perovskite of [FCH2CH2NH3][Mn(HCOO)3] has been successfully prepared by utilizing the ammonium of FCH2CH2NH3+, and it is the first example incorporating F‐substituted ammonium in the class of ammonium metal formate framework. The compound crystallizes in polar, orthorhombic space group Pna21, and the cell parameters are a=8.5901(3)–8.7158(6), b=8.4613(3)–8.5216(6), c=12.4837(4)–12.6106(9) Å and V=907.36(5)–936.6(1) Å3 from 80 K up to 410 K just before the decomposition, showing positive thermal expansions in all directions and no structural phase transition in the temperature region. The FCH2CH2NH3+ cation in the cavity of the NaCl‐like Mn‐formate framework adopts N−C−C−F gauche conformation, and its NH3+ and F ends are anchored to the anionic framework by N−H⋅⋅⋅O and C−H⋅⋅⋅F H‐bonds. The large dislocation of the NH3+ end from the anionic framework, about 1.4 Å, results in an estimated high electric polarization about 10 μCcm−2 for the polar structure. The material is also a spin‐canted antiferromagnet with the Néel temperature of 8.3 K. [ABSTRACT FROM AUTHOR]