Re-investigations of thermal decomposition of gadolinium sulfate octahydrate

摘要

The crystals of Gd₂(SO₄)₃·8H₂O were obtained by slow crystallization from a saturated solution previously received by dissolving Gd₂O₃ in an aqueous solution of sulfuric acid. The thermal behavior of this salt was studied using simultaneous DTA–TG technique under a nitrogen and air, in the temperature range of 298–1773 K. It was found that the dehydration of gadolinium sulfate octahydrate as well as thermal decomposition of anhydrous Gd₂(SO₄)₃ undergo in two steps. The existence of two polymorphic modification of anhydrous gadolinium sulfate has been confirmed. The new XRD data for high-temperature polymorph of Gd₂(SO₄)₃ were given. All intermediate products of dehydration and thermal decomposition were characterized by EPR method.