There are now many routes to the synthesis of YBa2Cu3O7-x. The method of mixing the oxides and heating them to 950°C is one of the earliest and seems to be the crudest. Nevertheless it seems that this is still the most widespread method used. Several high-temperature and other analytical techniques were performed on the superconductor prepared from BaCO3, Y2O3 and CuO. It was found that the superconductor retained significant amounts of carbonate up to temperatures above 1200°C. BaCO3 should be heated separately to about 1400°C before mixing with the other oxides, to prepare the superconductor at 950°C.