Cleve, Lecoq de Boisbaudran and others into erbia, holmia, thulia and dysprosia, but it is still doubtful whether any one of these four splitting products is a single substance.
It came to be called Stockholm ("the isle of the log," Latin Holmia, German Holm); the true explanation of the name is not known.
Mosander's erbia has been shown to contain various other oxides - thulia, holmia, &c. - but this has not yet been perfectly worked out.