UC Irvine

Neutron-diffraction measurements have been made on polycrystalline samples of UBe13 and ThBe13 at several temperatures between 10 and 250 K. Refinement of the powder patterns using the Rietveld method of profile analysis yields structural parameters in substantial agreement with previous work [space group Og6 (Fm3c); 8 U in 8(a); 8 Be(I) in 8(b); 96 Be(II) in 96(i)]. Values for the (y,z) coordinates of the 96 Be(II) are (0.1763, 0.1150) and (0.1745, 0.1129) for UBe13 and ThBe13, respectively. They correspond very closely to those values required for regular snub-cube coordination of the Be(II) around the uranium atoms. © 1985 The American Physical Society.