Understanding the complex structural features and phase changes in Na2Mg2(SO4)3: A combined single crystal and variable temperature powder diffraction and Raman spectroscopy study
this system. We show that room temperature Na2Mg2(SO4)3 can only be prepared by quenching from high temperature, with slow cooling leading to phase separation to give the previously unreported systems, Na2Mg(SO4)2 and Na2Mg3(SO4)4. We report the structures of quenched Na2Mg2(SO4)3 (monoclinic, P21 ), as well as Na2Mg(SO4)2 (triclinic, P1̅̅ ) and Na2Mg3(SO4)4 (orthorhombic, Pbca) , detailing their complex
4 ) 4 by doublereactions in Mg-Na 3 Al(SO 4 ) 3 mixtures is proposed. When the mixtures are calcinated at temperatures in the range 600–900 °C in an argon stream or an open atmosphere, a sodium-magnesium sulphate and alumina are obtained. A study of these doublereactions has allowed us to establish that the mechanism of formation of the compound Na 6 Mg(SO 4 ) 4 is an exchange reaction between MgO
摘要 提出了一种在Mg-Na 3 Al(SO 4 ) 3 混合物中通过双反应获得含氧盐Na 6 Mg(SO 4 ) 4 的方法。当混合物在氩气流或开放气氛中在 600-900 °C 的温度范围内煅烧时,得到钠-镁硫酸盐和氧化铝。对这些双反应的研究使我们能够确定化合物 Na 6 Mg(SO 4 ) 4 的形成机制是 MgO 和 Na 3 Al(SO 4 ) 3 之间的交换反应。在某些情况下,根据摩尔比 Mg/Al,还会形成尖晶石 MgAl 2 O 4。