1996 年 44 巻 1 号 p. 79-83
143Nd/144Nd isotopic ratio and rare-earth impurities are examined for high purity neodymium oxide prepared by six chemical companies. The isotopic ratios of the reagents are grouped into four and vary from 0.511463 to 0.512238. Some of the reagents contain impurities more than 1 ppm for lanthanum, cerium and samarium. A neodymium isotopic reference will be prepared according to the result.