Samples of nominal composition Pb1-xSbxSr2Ca1-yYyCu2O7-delta with 0 le
ss-than-or-equal-to x,y less-than-or-equal-to 1, synthesized at 900-de
grees-C in air, argon and oxygen, have been investigated. None of the
samples sintered in air or in oxygen was superconducting. Some of the
samples which were prepared in argon exhibited superconductivity. The
superconducting signal was not due to the ''1212-phase'', but probably
due to a ''2213-phase''.