The structures of four caesium tellurates

Cs2TeO3, Msub(r)=441.42, P321, a=6.790(1), c=7.972(1)A, U=318.3A3, Z=2, Dsub(x)=4.606 g cm-3, MoKα, lambda=0.71069 A, μ=157.8 cm-1, F(000)=372, room temperature, R=0.045 for 415 unique reflections. (2) Cs2Te2O5, Msub(r)=601.02, Pbca, a=12.102(1), b=12.092(2), c=10.760(2)A, U=1574.6A3, Z=8, Dsub(x)=5.070g cm-3, MoKα, lambda=0.71069 A, μ=164.5 cm-1, F(000)=2032, room temperature, R=0.060 for 2592 unique reflections. (3) Cs2Te4O9, Msub(r)=920.21, Ianti 42d, a=10.783(1), c=20.599(4)A, U=2394.9A3, Z=8, Dsub(x)=5.104 g cm-3, MoKα, lambda0=0.71069 A, μ=156.6 cm-1, F(000)=3120, room temperature, R=0.056 for 1616 unique reflections.(4) Cs2Te4O12, Msub(r)=968.21, Ranti 3m, a=7.2921(4), c=18.332(2)A, U=844.2AA3 [rhombohedral constants: a=7.4205(6)A, α=58.858(7)0, U=281.4A3], Z=3, Dsub(x)=5.713 g cm-3, MoKα, lambda=0.71069A, μ=166.8 cm-1, F(000)=1242, room temperature, R=0.043 for 622 unique reflections. Structures (1) and (2) are related to the perovskite structure. (3) and(4) are of the inverse pyrochlore type. In structures (1)-(3) Tesup(IV) atoms are octahedrally coordinated by oxygens and holes, the number of holes varying from 1 to 3. In Cs2Te4O12 the Tesup(IV) atom is at the centre of a very nearly regular octahedron of oxygens, an exceptional coordination for tetravalent Te. In this octahedron the length of the Te-O bonds is 2.104(7)A. (orig.)