The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi(NO3)3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffr...The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi(NO3)3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300g/L Bi(NO3)3 reacts at 90℃ for 2h, the Bi2O3 powders with 60nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2O3 powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi2O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi 3+ to O 2- changes easily during the formation of nano-Bi2O3 particles by a chemical precipitation method.展开更多
A new water-stable metal-organic framework,[Cu_2(bdc)_2(tpt)_3]·2H_2O(1,H_2 bdc = terephthalic acid,tpt = 2,4,6-tri(4-pyridinyl)-1,3,5-triazine),has been synthesized and characterized by elemental analysi...A new water-stable metal-organic framework,[Cu_2(bdc)_2(tpt)_3]·2H_2O(1,H_2 bdc = terephthalic acid,tpt = 2,4,6-tri(4-pyridinyl)-1,3,5-triazine),has been synthesized and characterized by elemental analysis,infrared(IR) spectrum,thermogravimetric analysis(TGA),powder X-ray diffraction(PXRD) and single-crystal X-ray diffraction. Compund 1 crystalizes in monoclinic,space group C2/c with a = 30.147(5),b = 11.0548(17),c = 20.867(4) ?,β = 115.035(2)o,C_(70)H_(48)Cu_2N_(18)O_(10),Mr = 1428.34,V = 6301.0(18) ?~3,Z = 8,D_c = 1.506 g/cm^3,μ = 0.754 mm^(–1),F(000) = 2928,GOOF = 1.058,λ(MoK α) = 0.71073 ?,the final R = 0.0387 and wR = 0.1091 for 6230 observed reflections with I 〉 2σ(I). In compound 1,the half metallacycles [Cu_2(tpt)_3] are linked by the bdc2-ligands to form a 1D bent ladder-like chain featured with a nano-sized channel,and these chains link each other via intermolecular hydrogen bonds and π-π stacking interactions to form a 3D supramolecular architecture with the voids filled with free water molecules. In addition,the water stability of 1 was investigated by PXRD patterns,which indicate that compound 1 keeps its structural integrity in boiling water for at least three days.展开更多
文摘The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi(NO3)3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300g/L Bi(NO3)3 reacts at 90℃ for 2h, the Bi2O3 powders with 60nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2O3 powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi2O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi 3+ to O 2- changes easily during the formation of nano-Bi2O3 particles by a chemical precipitation method.
基金supported by the 973 key program of the Chinese Ministry of Science and Technology(MOST)(2012CB821705)
文摘A new water-stable metal-organic framework,[Cu_2(bdc)_2(tpt)_3]·2H_2O(1,H_2 bdc = terephthalic acid,tpt = 2,4,6-tri(4-pyridinyl)-1,3,5-triazine),has been synthesized and characterized by elemental analysis,infrared(IR) spectrum,thermogravimetric analysis(TGA),powder X-ray diffraction(PXRD) and single-crystal X-ray diffraction. Compund 1 crystalizes in monoclinic,space group C2/c with a = 30.147(5),b = 11.0548(17),c = 20.867(4) ?,β = 115.035(2)o,C_(70)H_(48)Cu_2N_(18)O_(10),Mr = 1428.34,V = 6301.0(18) ?~3,Z = 8,D_c = 1.506 g/cm^3,μ = 0.754 mm^(–1),F(000) = 2928,GOOF = 1.058,λ(MoK α) = 0.71073 ?,the final R = 0.0387 and wR = 0.1091 for 6230 observed reflections with I 〉 2σ(I). In compound 1,the half metallacycles [Cu_2(tpt)_3] are linked by the bdc2-ligands to form a 1D bent ladder-like chain featured with a nano-sized channel,and these chains link each other via intermolecular hydrogen bonds and π-π stacking interactions to form a 3D supramolecular architecture with the voids filled with free water molecules. In addition,the water stability of 1 was investigated by PXRD patterns,which indicate that compound 1 keeps its structural integrity in boiling water for at least three days.