Patent ID: 8409543

Claim:
A method for preparing a pyrochlore oxide represented by a general formula A 2 B 2 O 7-z , where A and B each represent a metal element, where 0 ≦Z ≦1, where A contains A l that is at least one element selected from the group consisting of Pb, Sn, and Zn, and where B contains B 1 that is at least one element selected from the group consisting of Ru, W, Mo, Ir, Rh, Mn, Cr, and Re, the method comprising: forming a precipitate of the pyrochlore oxide by reaction of a halide or nitrate of said A and an alkaline metal acid of said B; and calcining the precipitate of the pyrochlore oxide at a temperature of at least 250° C. and at most 900° C. in an inert gas atmosphere.