In the superconductive lanthanum compounds La
2-xA
xCuO
4 (A=Sr, Ca, Ba), divalent ions were substituted with monovalent Na, K and divalent Pb. Only the substitution with Na resulted in a superconductivity, and the critical temperature (
Tc) is found to be 22.2K at the composition at La
1.5Na
0.5CuO
4 reacted at temperatures between 880 and 890°C. In another superconductive compound LaBa
2Cu
3O
7-y which has the same structure as YBa
2Cu
3O
7-y, divalent Ba ions were partially substituted with Ca
2+ and Sr
2+. In the compound LaBaSrCu
3O
7-y Tc deteriorates and two superconductive phases appear. On the contrary, in the compound LaBaCaCu
3O
7-y metalic behavior and a sharp transition in resistivity are found, i.e., its transition width (
ΔT) is within 3K. Further,
Tc is not much influenced by the sintering temperatures between 890 and 1, 050°C, and is reproducibly settled in between 74.7K and 77.4K. These results should be compared with those obtained in LaBa
2Cu
3O
7-y, in which
Tc largely depended on sintering temperature and
T amounts to 13.4K.
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