title: New cubic perovskite Na(Cu2.5Ti0.5)Ti4O12 with square planar coordination of Ti4+.
abstract: A new perovskite, Na[Cu(2.5)Ti(0.5)]Ti4O12, has been synthesized using a conventional solid-state technique. Neutron and synchrotron X-ray powder diffraction studies in combination with density measurements and bond-valence calculations have revealed that the material crystallizes in the cubic Im space group (a = 7.38472(2) A, Z = 2) with the square-plane site accommodating 16.7% of Ti4+. This is the highest level of non-Jahn-Teller cation substitution for Cu2+ reported to date for CaCu3Ti4O12-type perovskites prepared at ambient pressure.
authors.affiliation: Bragg Institute, ANSTO, PMB 1, Menai, NSW 2234, Australia. Maxim.Avdeev@ansto.gov.au
authors.forename: Maxim
authors.initials: M
authors.lastname: Avdeev
authors.forename: Vladimir B
authors.initials: VB
authors.lastname: Nalbandyan