THE STRUCTURE OF Yb (ND3)5.7

C. NÖLDEKE; P. DAMAY; W. PRESS; F. LECLERCQ; W. LIPPIK; M. FOUKANI

doi:doi:10.1051/jp4:1991539

Numéro		J. Phys. IV France Volume 01, Numéro C5, Décembre 1991 COLLOQUE WEYL VII International Conference on METALS IN SOLUTION


Page(s)		C5-339 - C5-344
DOI		https://doi.org/10.1051/jp4:1991539

COLLOQUE WEYL VII
International Conference on METALS IN SOLUTION

J. Phys. IV France 01 (1991) C5-339-C5-344
DOI: 10.1051/jp4:1991539

THE STRUCTURE OF Yb (ND₃)_5.7

C. NÖLDEKE¹, P. DAMAY², W. PRESS¹, F. LECLERCQ², W. LIPPIK¹ and M. FOUKANI²

¹ Institut für Experimentalphysik der Universität Kiel, Leibnizstrasse 19, D-2300 Kiel, Germany
² URA 253 du CNRS, HEI, 13 rue de Toul, F-59046 Lille cedex, France

Abstract
Neutron powder diffraction was performed on five Yb(ND₃)_x samples prepared with x = 5.5, 5.7, 5.9 6.0 and 6.3. Two different low temperature (2 K) structures are observed ; one (i) mainly showing peaks of a bcc lattice with a₀ = 9.076 Å but also weak sc peaks, the other (ii) presenting bcc peaks only with a₀ = 9.111 Å. At 17 K the sc peaks in (i) vanish, which indicates the presence of an order- disorder phase transition. For the orientationally disordered structure (ii), Yb(ND₃)_5.7, showing more disorder at low temperature, a structure refinement with cubic harmonic functions is given.