Solid solution perovskite phases AZrxTa1-xO2+xN1-x, with A = Ca, Sr, Ba and 0 less-than-or-equal-to x less-than-or-equal-to 1 have been synthesised by ammonolysis of mixtures of Ta-Zr gels and ACO3. The gels were made by the sol-gel technique using TaCl5 and Zr-n-propoxide as precursors. The perovskite phases have been characterised by X-ray powder diffraction and elemental analysis for one composition from each subsystem has been performed. The Ca compounds were found to be orthorhombic for all x. The orthorhombic GdFeO3 type perovskite structure was verified for the composition CaZr0.52Ta0.48O2.52N0.48 by a Rietveld refinement to R(F) = 2.3 %, using CuKalpa1 X-ray powder diffractometer data. According to X-ray powder diffraction data, the Sr compounds are orthorhombic for x greater-than-or-equal-to 0.60 and cubic for lower x values. The Ba compounds were found to be cubic for all x.