Abstract <p>X-ray powder diffraction and thermogravimetric analyses revealed the existence of three KNd(SO<sub>4</sub>)<sub>2</sub>∙H<sub>2</sub>O crystal hydrate phases, and their unit cell parameters were determined. The dehydration of KNd(SO<sub>4</sub>)<sub>2</sub>∙H<sub>2</sub>O upon heating at 250°C yields a partially dehydrated phase of approximate composition KNd(SO<sub>4</sub>)<sub>2</sub>∙0.2H<sub>2</sub>O. Further heating to 400°C ends with complete dehydration to yield anhydrous monoclinic KNd(SO<sub>4</sub>)<sub>2</sub>. The high-temperature triclinic KNd(SO<sub>4</sub>)<sub>2</sub> phase exists in the range 635–900°С and decomposes when heated above 900°С. The trigonal KNd(SO<sub>4</sub>)<sub>2</sub> phase forms solid solutions with the SrSO<sub>4</sub>·0.5H<sub>2</sub>O crystalline matrix. The anhydrous KNd(SO<sub>4</sub>)<sub>2</sub> phase does not form solid solutions with anhydrous orthorhombic SrSO<sub>4</sub>.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Phase Transformations in the KNd(SO4)2∙H2O–SrSO4∙0.5H2O System under Heating to 1000°С

  • N. N. Bushuev,
  • G. K. Tatosyan

摘要

Abstract

X-ray powder diffraction and thermogravimetric analyses revealed the existence of three KNd(SO4)2∙H2O crystal hydrate phases, and their unit cell parameters were determined. The dehydration of KNd(SO4)2∙H2O upon heating at 250°C yields a partially dehydrated phase of approximate composition KNd(SO4)2∙0.2H2O. Further heating to 400°C ends with complete dehydration to yield anhydrous monoclinic KNd(SO4)2. The high-temperature triclinic KNd(SO4)2 phase exists in the range 635–900°С and decomposes when heated above 900°С. The trigonal KNd(SO4)2 phase forms solid solutions with the SrSO4·0.5H2O crystalline matrix. The anhydrous KNd(SO4)2 phase does not form solid solutions with anhydrous orthorhombic SrSO4.