Phase Relations in the System NH4Ti2P3O12–NH4Zr2P3O12

Crystalline phases in the system NH4Ti2P3O12–NH4Zr2P3O12 were prepared in a high pressure vessel, and were investigated by X-ray method. New compounds, (NH4)1+xTi3+x(Ti4+,Zr)2−xP3O12 (1≥x), with the langbeinite-type structure were produced under reducing conditions.