K_2O·MgO·6B_2O_3·10H_2O的热化学研究(英文)

Thermochemistry of Dipotassium Magnesium Dodecaborate Decahydrate

在大约１ｍｏｌ·ｄｍ－３的盐酸水溶液中测定了Ｋ２Ｏ·ＭｇＯ·６Ｂ２Ｏ３·１０Ｈ２Ｏ的溶解焓。结合已获得的其它热化学数据，得出Ｋ２Ｏ·ＭｇＯ·６Ｂ２Ｏ３·１０Ｈ２Ｏ的标准摩尔生成焓为－（１２２５０．３５±９．６８）ｋＪ·ｍｏｌ－１，并利用“基团贡献法”计算出标准摩尔吉布斯自由能为－１１１０３ｋＪ·ｍｏｌ－１。从而计算出其标准摩尔生成熵和标准摩尔熵。

The enthalpies of solution of K2O·MgO·6B2O3·10H2O in approximately 1mol·dm-3 aqueous hydrochloric acid,and of KCI in aqueous（hydrochloric acid +boric acid +magnesium oxide )were determined. Together with the previously determined enthal- pies of solution of H3BO3 in approximately 1 mol· dm-3HCI（aq), and of MgO in aqueous (hydrochloric acid+boric acid ),the standard molar enthalpy of formation of-（12250. 35± 9. 68)kJ· mol-1 for K2O· MgO· 6B2O3· 10H2O was obtained from the standard molar en- thalpies of formation of MgO（s), H2BO3(s), KCI（s), and H2O（1). The standard molar en- tropy of formation of-3848. 23J. K-1· mol-1 and standard molar entropy of 765. 96 J· K-1· mol-1 for K2O· MgO· 6B2O3· 10H2O were calculated from the thermodynamic relations.