CS3TI5P7O29 - A TITANIUM(IV) PHOSPHATE-CONTAINING TIO5 TRIGONAL BIPYRAMIDS

A new ternary titanium phosphate, Cs3Ti5P7O29, has been synthesized an d structurally characterized by single-crystal X-ray diffraction. It c rystallizes in the triclinic space group P ($) over bar 1 with a = 6.3 07(1), b = 10.330(2), c = 20.230(3) Angstrom, alpha = 88.65(1), beta = 84.83(1), gamma = 72.37(1)degrees, Z = 2 and R = 0.0396. The structur e consists of tunnels where the caesium cations are located. The frame work is composed of two types of corner-sharing dimers of compositions Ti2O11 formed by two octahedra and Ti2O10 by an octahedron and a trig onal bipyramid, discrete TiO6 octahedra, PO4 tetrahedra and P2O7 group s. The structural formula is Cs3Ti(Ti2O)(2)(PO4)(5)(P2O7). Five-co-ord inate titanium with trigonal-bipyramidal geometry is unusual in phosph ates.