SUBSTITUTION OF LEAD FOR GADOLINIUM IN THE Pb8Na2(РO4)6 STRUCTURE AND ITS EFFECT ON THE ELECTROPHYSICAL PROPERTIES OF SOLID SOLUTIONS

The X-ray phase analysis method established the limit of substitution of lead for gadolinium according to the scheme 2Pb2+ → Gd3+ + Na+ in the formation of solid solutions with the structure of apatite based on double sodium lead phosphate Pb8-2xGdxM2+x(PO4)6. Changes in the parameters of the elementary cells of the obtained solid solutions confirm the course of substitution and are consistent with the difference in the ionic radii of the substituted ions. The features of the crystal structure of the resulting solid solutions have been studied by the method of X-ray diffraction analysis of the powder. The effect of lead substitution with gadolinium in sodium lead double phosphate with apatite structure on the conductivity of the obtained samples was determined.