They gave the new element the name Brevium ( Latin brevis , brief , short ) ; the name was changed to Protoactinium in 1918 when two groups of scientists ( Otto Hahn and Lise Meitner of Germany and Frederick Soddy and John Cranston of the UK ) independently discovered 231-Pa . They named the new element brevium ( from the Latin word , brevis , meaning brief or short ) because of its short half-life , 6.7 hours for . In 1918 , two groups of scientists , led by Otto Hahn and Lise Meitner of Germany and Frederick Soddy and John Cranston of Great Britain , independently discovered another isotope of protactinium , 231Pa having much longer half-life of about 32,000 years .