A highly polar hybrid perovskite of [FCH2CH3NH3][Mn(HCOO)3]

A new hybrid perovskite of [FCH 2 CH 3 NH 3 ][Mn(HCOO) 3 ] has been successfully prepared by utilizing the ammonium of FCH 2 CH 3 NH 3 + , 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 Pna 2 1 , 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) Å 3 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 FCH 2 CH 3 NH 3 + cation in the cavity of the NaCl-like Mn-formate framework adopts N−C−C−F gauche conformation, and its NH 3 + and F ends are anchored to the anionic framework by N−H···O and C−H···F H-bonds. The large dislocation of the NH 3 + 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 8.3 K.