The chemistry of the radio-elements / by Frederick Soddy.

  • Soddy, Frederick, 1877-1956.
Date:
1914
Catalogue details

Licence: In copyright

Credit: The chemistry of the radio-elements / by Frederick Soddy. Source: Wellcome Collection.

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    gous to thorium D and radium C^,. The series is thus quite straightforward (Fig. 9). Recent evidence of a small proportion, some i in 600, of faster a-rays of range about 6.1 cm. has, however, been ^AcA >AgB >AcC —^AcD VI IV V III IV Fig.O. Main Actinium Series. obtained.^^ If this is confirmed it means that actinium C must disintegrate according to a second slower 8-ray giving mode, with separate period about ten hours to produce a product giving a-rays and having a period estimated from their range, which is almost exactly that of actinium A, of about 0.003 second (Fig. 10). It is curious to note that the a-ray mode of radium C has a calculated period almost the same as that of the radium emanation, and no doubt Yl TV Fig.lO. Pi obable Actinium Series. there is method underlying these periods. But as the ac- tinium active deposit, ordinarily prepared, always contains a minute amount of recoiled actinium X, it is best to wait for the full results before accepting the scheme of Fig. 10. Confirmatory evidence of the correctness of the above schemes has recently been obtained by determining the range of the recoil products of thorium C and actinium C. As Wertenstein showed, the recoil products of an a-ray change have ranges in air and hydrogen proportional to the ranges of the a-rays expelled in the same change, and this, of course, is to be expected.^ The ranges are small, some 0.14 mm. of air at N.T.P. for radium D, but are