Ln(4)Re(6)O(19) (Ln=Ce, Pr) and Nd4Re5.5O19 compounds have been synthesized for the first time in sealed evacuated silica tubes and characterized by X-ray powder diffraction, electron diffraction and EDX analysis. The crystal structure of Nd4Re5.5O19 (S.G. 123, Z=2, a=8.9396(4) Angstrom) has been refined from X-ray powder data. The influence of the Ln size on the stability of the Ln(4)Re(6)O(19) structure is discussed. (C) 1998 Published by Elsevier Science S.A. All rights reserved.