A new magnesium borate MgO·3B 2 O 3 ·3.5H 2 O has been synthesized by the method o f phase transformation of 2MgO·2B 2 O 3 ·MgCl 2 ·14H 2 O in boric acid solution and characte rized by XRD,FT-...A new magnesium borate MgO·3B 2 O 3 ·3.5H 2 O has been synthesized by the method o f phase transformation of 2MgO·2B 2 O 3 ·MgCl 2 ·14H 2 O in boric acid solution and characte rized by XRD,FT-IR and Raman spectra as well as by TG.The structural formula of this compound was Mg[B 6 O 9 (OH) 2 ]·2.5H 2 O.The main polyborate anions and their interaction in borate aqueous solution of preparation reactio n have been proposed according to the Raman spectrum of borate solution.The relation between the existing forms of polyborate anions and the crystalliz ing solid phase has been gained.展开更多
The results of SCF CNDO-CO calculation on polymeric [(η5,μ-2,3-dihydro-1 , 3-di-borolyl)M](M= Cr, Mn, Fe, Co, Ni) indicate that polydecker sandwich compounds with odd valence electrons in each stacking unit (C3B2H5)...The results of SCF CNDO-CO calculation on polymeric [(η5,μ-2,3-dihydro-1 , 3-di-borolyl)M](M= Cr, Mn, Fe, Co, Ni) indicate that polydecker sandwich compounds with odd valence electrons in each stacking unit (C3B2H5)M have Peierls distorted structures, while those with even valence electrons are favorable to the formation of regular structures. The Band structures show that both LU and HO bands are d-bands for all of the polydecker sandwich compounds studied.展开更多
1 Introduction Chabocuo Lake is located in the territory of Gaize County Ali area Tibet,the altitude of the lake-surface is4505 m with a total area of 32 Km2.It is a typical sulfate type saline and rich in boron and l...1 Introduction Chabocuo Lake is located in the territory of Gaize County Ali area Tibet,the altitude of the lake-surface is4505 m with a total area of 32 Km2.It is a typical sulfate type saline and rich in boron and lithium.In the natural evaporation process,several mineral sylvites cocrystallize out,thus increases the difficulties for separating and展开更多
A new magnesium borate MgO·B 2O 3·4H 2O was synthesized by the method of phase transformation of double salt and characterized by XRD, IR spectra and TG. The structural formula of this compound was Mg[B ...A new magnesium borate MgO·B 2O 3·4H 2O was synthesized by the method of phase transformation of double salt and characterized by XRD, IR spectra and TG. The structural formula of this compound was Mg[B 2O(OH) 6]·H 2O. The enthalpy of solution of MgO·B 2O 3·4H 2O in HCl (1.0492 mol·L -1) was determined. With the incorporation of the standard molar enthalpies of formation of MgO (s), H 3BO 3 (s), and H 2O (l), the standard molar enthalpy of formation of -(3135.31±1.68) kJ·mol -1 of MgO·B 2O 3·4H 2O was obtained. Thermodynamic properties of this compound were also calculated by group contribution method.展开更多
文摘A new magnesium borate MgO·3B 2 O 3 ·3.5H 2 O has been synthesized by the method o f phase transformation of 2MgO·2B 2 O 3 ·MgCl 2 ·14H 2 O in boric acid solution and characte rized by XRD,FT-IR and Raman spectra as well as by TG.The structural formula of this compound was Mg[B 6 O 9 (OH) 2 ]·2.5H 2 O.The main polyborate anions and their interaction in borate aqueous solution of preparation reactio n have been proposed according to the Raman spectrum of borate solution.The relation between the existing forms of polyborate anions and the crystalliz ing solid phase has been gained.
基金Supported by the National Natural Science Foundation of China the Young Teacher's Foundation of the State Education Commission of China
文摘The results of SCF CNDO-CO calculation on polymeric [(η5,μ-2,3-dihydro-1 , 3-di-borolyl)M](M= Cr, Mn, Fe, Co, Ni) indicate that polydecker sandwich compounds with odd valence electrons in each stacking unit (C3B2H5)M have Peierls distorted structures, while those with even valence electrons are favorable to the formation of regular structures. The Band structures show that both LU and HO bands are d-bands for all of the polydecker sandwich compounds studied.
文摘1 Introduction Chabocuo Lake is located in the territory of Gaize County Ali area Tibet,the altitude of the lake-surface is4505 m with a total area of 32 Km2.It is a typical sulfate type saline and rich in boron and lithium.In the natural evaporation process,several mineral sylvites cocrystallize out,thus increases the difficulties for separating and
文摘A new magnesium borate MgO·B 2O 3·4H 2O was synthesized by the method of phase transformation of double salt and characterized by XRD, IR spectra and TG. The structural formula of this compound was Mg[B 2O(OH) 6]·H 2O. The enthalpy of solution of MgO·B 2O 3·4H 2O in HCl (1.0492 mol·L -1) was determined. With the incorporation of the standard molar enthalpies of formation of MgO (s), H 3BO 3 (s), and H 2O (l), the standard molar enthalpy of formation of -(3135.31±1.68) kJ·mol -1 of MgO·B 2O 3·4H 2O was obtained. Thermodynamic properties of this compound were also calculated by group contribution method.
