VARIATION OF THE LATTICE-PARAMETERS WITH THE CU-PB-BI RATIO IN LAYERED CUPRATES WITH THE GENERAL FORMULA (CU-1-(X+Y)[PBXBIY])SR2YCU2OZ (0.5-GREATER-THAN-OR-EQUAL-TO-X+Y-GREATER-THAN-OR-EQUAL-TO-0.3,Z-SIMILAR-TO-7)

We present a systematic study of the variation of lattice parameters for the nonsuperconducting cuprates with the compositions (Cu-1-(x+y)[PbxBiy])Sr2YCu2O2 (1212 structure). Nearly single phase samples are obtained for average valencies near three for cations on the metal site in the rocksalt layer, assuming Cu2+,Pb4+ and Bi5+. Although the valency of in-plane copper can formally be varied, the metal-insulator transition appears to be suppressed by carrier trapping due to oxygen disorder.