抄録
Using the thin-layer technique, phase equilibria in the open Cr2O3-P2O5-H2O system have been studied within the temperature range of 25-350°C at the molar ratio P2O5: Cr2O3=(3-10): 1. The diagram of the crystallization fields for stable phases of chromium(III) phosphates has been constructed. The following phosphates have been synthesized and identified by chemical analysis, X-ray powder diffraction. and thin-layer chromatography: triphosphates CrH2P3O10(forms I, II, and III), CrH2P3O10·4H2O (form III) CrH2P3O10·2H2O (form I); polyphosphate Cr(PO3)3(form G). X-ray studies have been performed for powder samples of CrH2P3O10 (form II) [monoclinic, space group P21/c with a=7.327(2), b=8.703(3), c=12.361(5) Å;β=112.93(3)°] and Cr(PO3)3 (form G) [triclinic, space group P1 or P1 with a=7.022(1), b=10.253(2), c=5.019(1) Å;α=92.32(3),β=92.49(1), γ=98.37(2)°].
