Thermal decomposition products of heteronuclear Cu-RE complexes, CuRE(dhbaen)(NO3)center dot nH(2)O (RE = La, Eu, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb, and Lu)

To facilitate the preparation of finer and more homogeneous CuREOx and to achieve a lowering of the formation temperature, heteronuclear CuRE(1:1) complexes, CuRE(dhbaen)(NO3). nH(2)O were synthesized as precursor. As it was expected for RE=La through Gd, only a mixture of CuO and CuRE2O4 was formed even when the complex decomposed at 800 degrees C since the Cu/RE ratio is 1. For RE=Y and Tb through Lu, Cu2RE2O5 was formed by way of CuO and RE2O3. The structure of the decomposed product is controlled by the coordination number and ionic size of RE ion. The minimum radius ratio for eightfold coordination of RE3+ ion suggests that preparation of homogeneous Cu:RE(1:1) oxide with Cu2Ho2O5 type structure is difficult for RE=La through Gd. (C) 1997 Elsevier Science S.A.