A new oxide was described which was derived from a cubic pyrochlore in which both the A-sites (Rb) and the anionic sites were partially occupied. It was proposed that this would permit the migration of Rb+ cations through well-defined 3-dimensional tunnels. It was found that the electrical conductivity reflected this assumption.

J.Isasi, M.L.Lopez, M.L.Veiga, C.Pico: Solid State Ionics, 1996, 89[3-4], 321-6