CRYSTAL-STRUCTURE AND MAGNETIC-BEHAVIOR OF THE URANIUM MONOGERMANIDE UGE

The crystallographic structure of the uranium monogermanide UGe has be en determined from single crystal X-ray diffraction data. UGe crystall izes with the orthorhombic ThIn type (Pbcm), a = 9.827(2) Angstrom, b = 8.932(7) Angstrom, c 5.841(2) Angstrom, Z = 12. Anisotropic refineme nts gave R = 0.044 and R(omega) = 0.048 for 986 reflections and 37 var iables. Uranium and germanium atoms each occupy three crystallographic positions. The uranium U(3) form endless metallic chains running alon g the c axis, with a U-U interatomic distance of 2.92 Angstrom. Magnet ic measurements on an annealed polycrystalline powder indicate a Curie -Weiss-type behavior down to 2 K and an average effective magnetic mom ent of 2.47 mu(B)/U. (C) 1997 Academic Press.