Hydrothermal synthesis of yttrium compounds

Abstract

The precipitate obtained from Y203/HCl solution and ammonia solution included a few crystalline compounds and changed to low crystalline Y2O3 by washing by hot water. When the washed precipitate was hydrothermally treated at 200°C for 24 hr, α-Y(OH)3 was obtained at higher pH and it coexisted with an unknown phase at low pH. When the mixture of Y2O3/HCl solution and ammonia solution was hydrothermally treated, 6 compounds including Cl were formed at different pH.