【摘要】 采用改进的半微量相平衡法研究了Dy（NO₃）₃·3H₂O—18C₆—C₂H₅OH三元体系在25℃时的溶解度。溶解度曲线与配合物Dy（NO₃）₃·18C6·3H₂O·C₂H₅OH的固相相对应;饱和溶液的折光率曲线与溶解度曲线相对应。在液相和固相中,H₂O与Dy（NO₃）₃的摩尔比均为3:1,制得配合物的组成为Dy（NO₃）₃·18C6·3H₂O。用UC、IR、DTG及TG等手段研究了该配合物的性质。更多还原

【Abstract】 In this paper the solubility of ternary system, Dy（NO₃）₃·3H₂O-18C6-C₂H₅OH, at 25℃ have been investigated by a self-developed method semic-micrograpy for the study of phase equilibrium. Results indicate that the only one solubility curve of this ternary system corresponds to the solid phase of the complex Dy（NO₃）₃. 18C6 3H₂O·C₂H₅OH. The curve of refractive indexes for saturated solutions consists of only one branch line, which also corresponds to the solubility curve. Other complex species with different Dy/crown ratio is not found.Bohaviour of water in this system during equilibrium has been examined. Results show that the mole ratio, H₂O/Dy（NO₃）₃, is always equal to 3:1, no matter it is in liquid or solid phase.This complex has been isolated from organic solvent C₂H₅OH. As determined by chemical analysis, its composition is Dy（NO₃）₃·18C₆·3H₂O, which differs from the composition of the complex at equilibrium with the mother solution.The UV-spectra for the complex and 18C6 show that their maximum absorption bands are the same, but the extinction coefficients remarkably diffirent. These facts indicate that the complex is formed.The infrared spectra were recorded on an IR-440 spectrophotometer. It provi des definite evidence that the dysprosium ion is complxed with the crown ether 18C6. The infrared bands attributed to the nitrate groups in the complex support the presence of bidentate nitrate ligands.Thermogravimetry（TG） and differential thermogravimetry（DTG）data were obtained simultaneously by the use of TGS-2 thermoanalyzer. According to the TG curve the thermal decomposition of the complex may be considered as follows:Dy（NO₃）₃·18C6·3H₂O→Dy（NO₃）₃·18C6→4Dy（NO₃）₃·3（18C6）→DyONO₃→Dy₂O₃Weight loss measurement of the complex also confirms the authors’ assumption shown above!更多还原