[412] Amer. Chem. J. 1895, 17, 154.
[413] Rowland, Chem. News, 1894, 70, 68; compare also Crookes, ibid. 70, 81-82. Bettendorff (see Böhm, Die Darstellung der seltenen Erden, I. 480) has also used the method.
[414] See also Meyer and Wuorinen (loc. cit.).
Egan and Balke[415] have recently found the ratio Yt₂O₃ : 2YtCl₃ to be very suitable as a basis for atomic weight determinations; the oxide is converted into the anhydrous chloride in a quartz flask. In a preliminary experiment, they obtain as a mean of three consistent determinations the provisional value 90·12; the yttria employed was considered to contain not more than one-half per cent. of erbia.
[415] J. Amer. Chem. Soc. 1913, 35, 365.
Recent work by Meyer and his co-workers[416] indicates that the accepted value is too high. Preliminary work with the synthetic sulphate method gave the values (corrected) 88·71 and 88·73; the mean value of six analytical sulphate determinations, made on material carefully purified by the iodate method, was 88·75, the extreme values being 88·71 and 88·76. They consider that the true atomic weight is 88·7, the value of the second decimal figure being a little uncertain.
[416] Meyer and Wuorinen; Meyer and Weinheber, loc. cit.
Detection.
—The spark spectrum of yttrium has been examined by many authors, and the ultraviolet as well as the visible regions have been mapped; vide Exner and Haschek; Eder and Valenta, also Becquerel.[417]
[417] Compt. rend. 1908, 146, 683.