Phases containing tungsten in Cu(1) positions

A tetragonal (123) phase of composition CdBa2Cu2WO8 with the complete and selective substitution of tungsten atoms for copper in the Cu(1) positions is synthesized from CdWO4 and BaCuO2 at 800°C in flowing oxygen. The percentage of the (123) phase in the sample is at least 90%; the unit cell parameters are a = b = 0.4151(3) nm, c = 1.2537(8) nm. The X-ray diffraction pattern shows a superstructure with all three of the unit cell parameters being doubled.