AMBIENT-PRESSURE SYNTHESIS OF TETRAGONAL SR2CUO3+X

We report the synthesis of the ''high pressure'' tetragonal form of Sr 2CuO3+x by direct reaction of stoichiometric mixtures of oxide, peroxi de or carbonate of strontium and copper oxide intimately grounded in a ball mill for long periods of time. We present thermogravimetric anal ysis. We have determined that this phase can be obtained in the temper ature range between 350 to 450 degrees C. Above this temperature the o rthorhombic structure is more stable. All the obtained samples are non -superconducting in contrast to the high-pressure obtained samples.