After comparing the influences of each rare earth(Ⅲ),11 species of metal(Ⅱ)and 8 species of acidic triphenylmethane dye on the formation of coloured coordination compound in the system of Metal(Ⅱ)-RE (Ⅲ)-Dye,it wa...After comparing the influences of each rare earth(Ⅲ),11 species of metal(Ⅱ)and 8 species of acidic triphenylmethane dye on the formation of coloured coordination compound in the system of Metal(Ⅱ)-RE (Ⅲ)-Dye,it was proven that the co-colouration effect can be caused only by the xanthene dyes(XD)con- taining substituting hydroxy.group on the ortho-position of etheric oxygen group.Besides,the radius of met- al(Ⅱ)must not be smaller than a definite limit;otherwise,no co-colouration appears.Furthermore,the acid- ity of medium is another important factor to affect co-colouration,Bromopyrogallol red causes co-colouration of Pb(Ⅱ)-RE(Ⅲ)only,owing to its higher chromophoric acidity;while alizarin violet causes co-colouration of M(Ⅱ)-RE(Ⅲ)(M=Pb,Ca,Sr and Ba),due to its lower chromophoric acidity.The condi- tions causing co-colouration,the regularities of co-colouration and the influences of co-colouration in photometric determination of metals were discussed.展开更多
In co-colouration systems of rare earth(Ⅲ) with a metal(Ⅱ), induced colouration and decolouration ef- fects between different rare earths have been discovered. A sensitive co-colouration system of 《Lead(Ⅱ)-Rare Ea...In co-colouration systems of rare earth(Ⅲ) with a metal(Ⅱ), induced colouration and decolouration ef- fects between different rare earths have been discovered. A sensitive co-colouration system of 《Lead(Ⅱ)-Rare Earth(Ⅲ)-Alizarin Violet-Sensitizer》 was chosen as a typical one to study; and neodymium, gadolinium and yttrium were used to represent light, middle and heavy rare earths respectively. Semiquantitative relationships for the induced effects between yttrium and neodymium as well as between gadolinium and neodymium have been determined and discussed. In the presence of a sensitizer, these metal ions cannot always be coloured by alizarin violet when each of them is present alone, but a very sensitive co-colouration or co-decolouration may occur during their coexistence under certain conditions. If these metals exist as foreign ions in the photometric determination of another metal, serious unperceivable interference will possibly occur. Moreover, the condi- tions leading to induced co-colouration and co-decolouration are very complicated, so that close attention must be paid to this area in the photometric determination of certain metals.展开更多
文摘After comparing the influences of each rare earth(Ⅲ),11 species of metal(Ⅱ)and 8 species of acidic triphenylmethane dye on the formation of coloured coordination compound in the system of Metal(Ⅱ)-RE (Ⅲ)-Dye,it was proven that the co-colouration effect can be caused only by the xanthene dyes(XD)con- taining substituting hydroxy.group on the ortho-position of etheric oxygen group.Besides,the radius of met- al(Ⅱ)must not be smaller than a definite limit;otherwise,no co-colouration appears.Furthermore,the acid- ity of medium is another important factor to affect co-colouration,Bromopyrogallol red causes co-colouration of Pb(Ⅱ)-RE(Ⅲ)only,owing to its higher chromophoric acidity;while alizarin violet causes co-colouration of M(Ⅱ)-RE(Ⅲ)(M=Pb,Ca,Sr and Ba),due to its lower chromophoric acidity.The condi- tions causing co-colouration,the regularities of co-colouration and the influences of co-colouration in photometric determination of metals were discussed.
文摘In co-colouration systems of rare earth(Ⅲ) with a metal(Ⅱ), induced colouration and decolouration ef- fects between different rare earths have been discovered. A sensitive co-colouration system of 《Lead(Ⅱ)-Rare Earth(Ⅲ)-Alizarin Violet-Sensitizer》 was chosen as a typical one to study; and neodymium, gadolinium and yttrium were used to represent light, middle and heavy rare earths respectively. Semiquantitative relationships for the induced effects between yttrium and neodymium as well as between gadolinium and neodymium have been determined and discussed. In the presence of a sensitizer, these metal ions cannot always be coloured by alizarin violet when each of them is present alone, but a very sensitive co-colouration or co-decolouration may occur during their coexistence under certain conditions. If these metals exist as foreign ions in the photometric determination of another metal, serious unperceivable interference will possibly occur. Moreover, the condi- tions leading to induced co-colouration and co-decolouration are very complicated, so that close attention must be paid to this area in the photometric determination of certain metals.
