A black material A was prepared by heating 0.3978g of CuO,0.1480g of BaCO3, and 1.5069g of La2O3 to 700C under N2 and rapidly cooling to room temperature. A contains 15.79% O by mass and exhibited no weight loss on heating under a flow of He. A second black material B was prepared by heating La2CuO4 to 1070C for 17 hours in air and then slowly cooled under flow of O2. When 20mg of B was heated to 380C under flow of Ar, it lost 0.059mg. Calculate the chemical formulae