PREPARATION AND STRUCTURE OF THE YTTRIUM PHOSPHATE DIHYDRATE YPO₄·2H₂O

摘要

The yttrium phosphate dihydrate YPO_(4)·2H_(2)O was synthesized by thin-layer technique, and its crystal structure was obtained from X-ray powder diffraction data at room temperature. The structure of YPO_(4)·2H_(2)O was solved by direct methods and refined using the Rietveld analysis. The compound crystallizes in the monoclinic space group C2/c, with unit cell dimensions a = 6.15326(3), b = 14.99687(8), c = 5.57848(3) ?, β = 115.4319(4)°, V = 464.896(4) ?~(3), Z = 4. It has the gypsum-type crystal structure, with metal-phosphate 2D polymeric network, parallel to the ac plane. Water molecules, coordinated by the yttrium atoms, provide hydrogen bonding between the layers, resulting into a three-dimensional network. The crystal structure of YPO_(4)·2H_(2)O is compared with that of isotypic Y_(1-x)(Gd,Dy,Er)_(x)PO_(4)·2H_(2)O (x = 0.053), investigated earlier.