摘要
The isotopic ratio R_(191/193)of iridium in minerals and reagents was precisely measured by ther- mal ionization mass spectrometry with Daly ion detection.The mean R_(191/193)was found to be 0.5945(9), yielding the isotopic abundance as 37.29(3)atom％^(191)Ir and 62.71(3)atom％^(193)Ir.Together with known nuclidic masses,the atomic weight od iridium calculated therefrom is 192.216(1)at 2SD basis,or 192.217(2)when the instrument was calibrated with the absolute isotopic ratio of rhenium.
The isotopic ratio R_(191/193)of iridium in minerals and reagents was precisely measured by ther- mal ionization mass spectrometry with Daly ion detection.The mean R_(191/193)was found to be 0.5945(9), yielding the isotopic abundance as 37.29(3)atom％^(191)Ir and 62.71(3)atom％^(193)Ir.Together with known nuclidic masses,the atomic weight od iridium calculated therefrom is 192.216(1)at 2SD basis,or 192.217(2)when the instrument was calibrated with the absolute isotopic ratio of rhenium.
