Systematic prediction of new inorganic ferroelectrics in point group 4

The latest release of the Inorganic Crystal Structure Database contains a total of 87 entries corresponding to 70 different materials in point group 4. The structures reported for 11 materials in space group P4 satisfy the criteria for ferroelectricity, as do four in P4(1), one each in P4(2) and P4(3), 12 in I4, including seven that form three families, and another three in I4(1). Three previously known ferroelectrics were also listed in I4 and one in I4(1). In addition, the listing for point group 4 contains 22 entries for nonferroelectric materials and three with misassigned space groups. Among the newly predicted ferroelectrics in point group 4, assuming the validity of the underlying structural reports, are Ce5B2C6, modulated NbTe4, Na3Nb12O31F, Ca2FeO3Cl, K4CuV5O15Cl, TlBO2, CrOF3, PbTeO3, VO(HPO3)(H2O). 3H(2)O, MgB2O(OH)(6), beta-tetragonal boron, CuBi2O4, WOBr4, Na8PtO6, SbF2Cl3, Ba1.2Ti8O16, Ni[SC(NH2)(2)](4)Cl-2, Ca2SiO3Cl2, the mineral caratiite, NbAs, beta-NbO2 and Ag3BiO3.