Samarium atomic weight

Neodymium, determination of atomic weight of, in neodymium oxalate, 2 61 separation of, from samarium from monazite, as magnesium nitrate double salt, 2 56, 57... 

Naturally, Brauner did not obtain pentavalent didymium . We know now that lanthanides cannot reach this oxidation state. However, trying to determine the atomic mass of didymium more correctly, Brauner decided to obtain the element in as pure a form as possible. He discovered that didymium separated from samarium could be divided into three fractions somewhat differing in molecular weights. Brauner performed this experiment in 1883 but he had to stop further research for some reasons. It was a great pity since he was so close to ending the story of the old didymium . 

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