SYNTHESIS AND SUPERCONDUCTING PROPERTIES OF THE FLUORITE BLOCK SYSTEM[Y CE]2SR2-XBAXCU3O9-Z SUBSTITUTED BY OXY-ANIONS (BO3(3-), SO4(2-), PO4(3-))/

The partial substitution of the oxy-anions BO33-, SO42-, and PO43- for Cu has been successfully achieved in [Y/Ce]2Sr2-xBaxCu3O9-z. The high est substitution level (80% replacement of the ''chain'' Cu sites) was observed for BO33- ions, and was accompanied by a significant reducti on in the unit cell c axis length. For SO42- and PO43- groups, the sub stitution limit was lower (similar to 25% of the ''chain'' Cu sites). The samples were non-superconducting as prepared, but superconductivit y (T-c onset similar to 15-20K) could be induced by annealing in a hig h pressure oxygen atmosphere.