New Ferroelectric Inorganic Materials Predicted in Point Group 4mm

The Inorganic Crystal Structure Database containg a total of 209 entries for 128 different materials reported in point group 4mm, 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 P42nm, one in P4cc, two in P42mc, one in P42bc, seven in 14mm, two in 14cm, one in 141md and two in 14led. 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 4mm include K2[Pt(CN)4]Br0.3.3H20, Ndo.33TaO3, YBaCuFeO5+~, Ba2(TiO)(Si207), K2(NbO)2(SiO3)4, Ba6CoNb9030, SrESbMnO6, Hg2A1F 5.(HzO)2 , RbsNb3OF18 and