New ferroelectric inorganic materials predicted in point group 4mm

Abstract

The Inorganic Crystal Structure Database containing a total of 209 entries for 128 different materials reported in point group 4 mm, of which eight are for previously known ferroelectrics. Analysis of the remaining entries, assuming the structure determinations reported are correct, leads to the prediction of an additional 43 new ferroelectric materials. 15 were determined in space group P4mm, 11 in P4bm, one in P42 nm, one in P4cc, two in P42 mc, one in P42 bc, seven in I4mm, two in I4cm, one in I41 md and two in I41 cd. Numerous other structures are shown to have been assigned, most likely, to an incorrect space group. All but one of the materials reported in space group P4bm are predicted to be ferroelectric. New ferroelectrics predicted in point group 4 mm include K2[Pt(CN)4]Br0.3.3H2O, Nd0.33TaO3, YBaCuFeO5+δ, Ba2(TiO)(Si2O7), K2(NbO)2(SiO3)4, Ba6CoNb9O30, Sr2SbMnO6, Hg2AlF5.(H2O)2, Rb5Nb3OF18 and SrNi2(VO4)2.