Crystal Structure of Barium and Europium at 293, 78, and 5°K

Reasons are reviewed for suspecting that it may be possible to induce phase transformations in barium and europium. X-ray diffraction patterns at 78°K and 5°K, however, revealed no transformation from the normal body-centered cubic structure; there was none, also, after cold work at 5°K. The lattice constants at 5°K are 4.551±0.003 A for europium, 5.000±0.002 A for barium.