A precision X-ray diffraction (XRD) study of PbFe0.5Nb0.5O3 crystal in
the paraelectric phase at 160 degrees C has shown the effective therm
al parameters of Pb atoms to be larger than those of other atoms. Pb a
toms have substantial displacements from their special positions in an
ideal perovskite structure along the twelve [110] directions. The fin
al discrepancy factor R is 5.80%.