2 0 Ju l 2 01 7 Rattling mode and symmetry lowering resulting from instability of B 12-molecule in LuB

N.Sluchanko, 2, ∗ A.Bogach, N.Bolotina, V.Glushkov, 2 S.Demishev, 4 A.Dudka, V.Krasnorussky, O.Khrykina, K.Krasikov, V.Mironov, V.Filipov, and N.Shitsevalova Prokhorov General Physics Institute, Russian Academy of Sciences, 38 Vavilov Str., 119991 Moscow, Russia National University of Science and Technology (MISiS), 119049 Moscow, Russia Shubnikov Institute of Crystallography of Federal Scientific Research Centre Crystallography and Photonics of Russian Academy of Sciences, 59 Leninskii Ave., 119333 Moscow, Russia Moscow Institute of Physics and Technology (State University), 9 Institutskiy Per., 141700 Dolgoprudny, Russia Frantsevich Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, 3 Krzhyzhanovsky Str., 03680 Kiev, Ukraine (Dated: July 10, 2017)