Single phase sodium zirconium orthophosphates [NaZr2(PO4)(3) and Na2Zr(PO4)(2)] and zirconium diphosphate (ZrP2O7) have been synthesized. The measured linear expansion coefficient of NaZr2(PO4)(3) was rather small only reaching a value of 0.16% at 800 degrees C. The expansion coefficients of Na2Zr(PO4)2 and ZrP(2)O7 were also rather small and were 1.4 and 1.0% respectively at 800 degrees C. These phosphates showed different behaviour depending on the type of thermal pretreatment before the measurement of the expansion coefficient.