Novel lead-rich pyrochlore type compounds are described having the formula:Pb.sub.2 [M.sub.2-x Pb.sub.x ]O.sub.7-ywherein M is selected from the group consisting of Ru, Ir and mixtures thereof and wherein x is greater than 0 and less than or equal to about 1.2 and y is greater than or equal to 0 and less than or equal to about 1.0. A method of synthesizing these compounds is also described. The method involves the solid state reaction of a lead source and a ruthenium source and/or an iridium source at temperatures below about 600.degree. C in an oxygen-containing environment.