VAPOR COMPLEXES OF SAMARIUM(III) AND SAMARIUM(II) CHLORIDES WITH ALUMINUM(III) CHLORIDE

被引:71
作者
PAPATHEODOROU, GN
KUCERA, GH
机构
[1] Chemical Engineering Division, Argonne National Laboratory, Argonne
关键词
D O I
10.1021/ic50192a038
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
The electronic absorption spectra of vapor-phase compounds formed by reacting SmCl3(s) and SmCl2(s) with gaseous Al2Cl6 have been measured at temperatures up to 800 K and total pressures up to 13 atm. The spectra of the pale yellow SmIII-Al-Cl gaseous complex(es) were characteristic of the f→f electronic transitions of Sm(III). The spectra of the red-brown SmII-Al-Cl gaseous complex(es) showed high-intensity, broad bands which are attributed to 4f→5d transitions of Sm(II). Spectrophotometric measurements have been used to investigate the partial pressures of the vapor complexes at different Al2Cl6 pressures. Thermodynamic considerations suggest that the SmAl3Cl12 is the predominant vapor species formed by the trivalent samarium. For the reaction SmCl3(s)+3/2Al2Cl6(g)→SmAl3Cl12(g) the values of ΔH=6.7 kcal/mol and ΔS=-1.0 eu have been derived. At 650 K the volatility enhancement of Sm(II) has been estimated to be ~1010. Rare earth oxides have been halogenated and vapor transported using Al2Cl6 or Al2Br6. A new method for the preparation of anhydrous rare earth halide crystals is suggested. The data are discussed in terms of the systematics of formation and structure of gaseous lanthanide chloride complexes. © 1979, American Chemical Society. All rights reserved.
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页码:385 / 389
页数:5
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