Formation of Infinite-Layered (Ca1-xSrx) CuO2 and NaCuO2-type (Ca1-yNay)0.85CuO2 in Tartrate Route

Both NaCuO₂-type Ca_0.85CuO₂ and infinite-layered (Ca_{1- x} Sr _x )CuO₂ could be prepared much more easily by firing the dried solids from mixed acetate aqueous solutions titrated with tartaric acid than by normal calcination. The presence of a narrow solid-solution composition range of 0.10 < x > 0.16 was confirmed in infinite-layered (Ca_{1- x} Sr _x )CuO₂ in the preparation using the tartrate route. The calcium could also be substituted by sodium in a range of y > 0.15 in NaCuO₂-type (Ca_{1- y} Na _y )_0.85CuO₂ using the same route. Further substitution of Ca²⁺ with Y³⁺ might also be possible in infinite-layered (Ca_{1- x} Sr _x )CuO₂, but resulted in the NaCuO2-type compound in the substitution with Na⁺.