Both whisker and nanometer MgSO4·5Mg(OH)2·3H2O(MOS) were prepared by hydrothermal method at 140℃for different times, using NaOH and MgSO4·7H2O as raw materials. The MgSO4·5Mg(OH)2·3H2O part i...Both whisker and nanometer MgSO4·5Mg(OH)2·3H2O(MOS) were prepared by hydrothermal method at 140℃for different times, using NaOH and MgSO4·7H2O as raw materials. The MgSO4·5Mg(OH)2·3H2O part icles were characterized by powder X ray diffraction(XRD),thermal analysis(TGA DSC), infrared spectroscopy(FT IR),transmission electron microscopy(SEM) and scanning electron microscopy(TEM). The size distribution in whisker like and nanocrystalline materials arein the range of 10～50μm and 10～20nm respectively. The whisker MOS is metastable phase in MgSO4 NaOH H2O system at 140℃,whereas nanometer MOS is stable phase.展开更多
The new mixed borates with formula(Rb 2 Ca [B 4 O 5 (OH) 4 ] 2 ·8H 2 O and Cs 2 Ca [B 4 O 5 (OH) 4 ] 2 ·8H 2 O)were prepared by reaction Rb (Cs )-borate aqueous solution with CaCl 2 .Two kinds of compounds w...The new mixed borates with formula(Rb 2 Ca [B 4 O 5 (OH) 4 ] 2 ·8H 2 O and Cs 2 Ca [B 4 O 5 (OH) 4 ] 2 ·8H 2 O)were prepared by reaction Rb (Cs )-borate aqueous solution with CaCl 2 .Two kinds of compounds were characterized by chemical analysis,X-ray powder dif fraction,FT-IR spectra and thermal analysis.展开更多
Hydrated potassium monoborate(KBO 2 ·4/3H 2 O)was obtained from an aqueous solutio n in a mole ratio of K 2 O∶B 2 O 3 =2∶1and characterized by powder X-ray diffraction(XRD),infrared spectroscopy(FT-IR)and Raman...Hydrated potassium monoborate(KBO 2 ·4/3H 2 O)was obtained from an aqueous solutio n in a mole ratio of K 2 O∶B 2 O 3 =2∶1and characterized by powder X-ray diffraction(XRD),infrared spectroscopy(FT-IR)and Raman spectroscopy.The enthalpy of solut ion of hydrated potassium monoborate,KBO 2 ·4/3H 2 O,in approximately1mol·dm -3 aqueous hydrochloric acid was determined.Together with the previously determined enthalpies of so-lution of H 3 BO 3 in approximately 1mol·dm -3 HCl (aq),and of KCl in aqueous(hydrochloric acid +boric acid),the standard molar enthalpy of forma tion of -(1411.11±0.84)kJ·mol -1 for KBO 2 ·4/3H 2 O was obtained from the standard molar enthalpies of formation of KCl (s),H 3 BO 3 (s),and H 2 O(l).The standard molar entropy of formation of -422.94J ·K -1 ·mol -1 and standard molar entropy of 163.47J·K -1 ·mol -1 for KBO 2 ·4/3H 2 O were calculated from the thermodynamic relations.A group contribution method is applicable to KBO 2 ·4/3H 2 O.展开更多
In this paper,hydrothermal phase reaction in MgSO4NaOHH2O quarternary reciprocal system at 160℃ has been studied.There appear four solid phases,corresponding to Mg(OH)2,5Mg(OH)2·MgSO4·2H2O,3...In this paper,hydrothermal phase reaction in MgSO4NaOHH2O quarternary reciprocal system at 160℃ has been studied.There appear four solid phases,corresponding to Mg(OH)2,5Mg(OH)2·MgSO4·2H2O,3Mg(OH)2·MgSO4·H2O and 2Mg(OH)2·MgSO4 respectively.The solid phases were determined by Chemical analysis,and characterized by both XRD and microphotograph.The MgSO4 concentration affects morphology of MOS(5Mg(OH)2·MgSO4·2H2O) whisker.展开更多
Using MgSO4 and NaOH solutions as starting materials, the whisker of 5Mg(OH)2·MgSO4·2H2O has been prepared by hydrothermal method at 160℃ for different time. The whisker was separated, washed by water, etha...Using MgSO4 and NaOH solutions as starting materials, the whisker of 5Mg(OH)2·MgSO4·2H2O has been prepared by hydrothermal method at 160℃ for different time. The whisker was separated, washed by water, ethanol and ether,and characterized by chemical analysis, XRD, IR and microphotography. The growth time of whisker would affect its morphology.展开更多
文摘Both whisker and nanometer MgSO4·5Mg(OH)2·3H2O(MOS) were prepared by hydrothermal method at 140℃for different times, using NaOH and MgSO4·7H2O as raw materials. The MgSO4·5Mg(OH)2·3H2O part icles were characterized by powder X ray diffraction(XRD),thermal analysis(TGA DSC), infrared spectroscopy(FT IR),transmission electron microscopy(SEM) and scanning electron microscopy(TEM). The size distribution in whisker like and nanocrystalline materials arein the range of 10～50μm and 10～20nm respectively. The whisker MOS is metastable phase in MgSO4 NaOH H2O system at 140℃,whereas nanometer MOS is stable phase.
文摘The new mixed borates with formula(Rb 2 Ca [B 4 O 5 (OH) 4 ] 2 ·8H 2 O and Cs 2 Ca [B 4 O 5 (OH) 4 ] 2 ·8H 2 O)were prepared by reaction Rb (Cs )-borate aqueous solution with CaCl 2 .Two kinds of compounds were characterized by chemical analysis,X-ray powder dif fraction,FT-IR spectra and thermal analysis.
文摘Hydrated potassium monoborate(KBO 2 ·4/3H 2 O)was obtained from an aqueous solutio n in a mole ratio of K 2 O∶B 2 O 3 =2∶1and characterized by powder X-ray diffraction(XRD),infrared spectroscopy(FT-IR)and Raman spectroscopy.The enthalpy of solut ion of hydrated potassium monoborate,KBO 2 ·4/3H 2 O,in approximately1mol·dm -3 aqueous hydrochloric acid was determined.Together with the previously determined enthalpies of so-lution of H 3 BO 3 in approximately 1mol·dm -3 HCl (aq),and of KCl in aqueous(hydrochloric acid +boric acid),the standard molar enthalpy of forma tion of -(1411.11±0.84)kJ·mol -1 for KBO 2 ·4/3H 2 O was obtained from the standard molar enthalpies of formation of KCl (s),H 3 BO 3 (s),and H 2 O(l).The standard molar entropy of formation of -422.94J ·K -1 ·mol -1 and standard molar entropy of 163.47J·K -1 ·mol -1 for KBO 2 ·4/3H 2 O were calculated from the thermodynamic relations.A group contribution method is applicable to KBO 2 ·4/3H 2 O.
文摘In this paper,hydrothermal phase reaction in MgSO4NaOHH2O quarternary reciprocal system at 160℃ has been studied.There appear four solid phases,corresponding to Mg(OH)2,5Mg(OH)2·MgSO4·2H2O,3Mg(OH)2·MgSO4·H2O and 2Mg(OH)2·MgSO4 respectively.The solid phases were determined by Chemical analysis,and characterized by both XRD and microphotograph.The MgSO4 concentration affects morphology of MOS(5Mg(OH)2·MgSO4·2H2O) whisker.
文摘Using MgSO4 and NaOH solutions as starting materials, the whisker of 5Mg(OH)2·MgSO4·2H2O has been prepared by hydrothermal method at 160℃ for different time. The whisker was separated, washed by water, ethanol and ether,and characterized by chemical analysis, XRD, IR and microphotography. The growth time of whisker would affect its morphology.
