 In 1907 , the French chemist Georges Urbain separated Marignac 's ytterbia into two components : neoytterbia and lutecia . Neoytterbia would later become known as the element ytterbium , and lutecia would later be known as the element lutetium . The Austrian chemist Carl Auer von Welsbach independently isolated these elements from ytterbia at about the same time , but he called them aldebaranium and cassiopeium ; the American chemist Charles James also independently isolated these elements at about the same time . Urbain and Welsbach accused each other of publishing results based on the other party . The Commission on Atomic Mass , consisting of Frank Wigglesworth Clarke , Wilhelm Ostwald , and Georges Urbain , which was then responsible for the attribution of new element names , settled the dispute in 1909 by granting priority to Urbain and adopting his names as official ones , based on the fact that the separation of lutetium from Marignac 's ytterbium was first described by Urbain ; after Urbain 's names were recognized , neoytterbium was reverted to ytterbium . 
