PREPARATION OF SINGLE-CRYSTALS OF LAAL AND X-RAY STRUCTURE DETERMINATION

Single crystals of the compound LaAl have been prepared by the reactio n of a mixture of lanthanum and aluminium under nitrogen at 950 degree s C. Previously reported crystal structure data determined by X-ray po wder diffraction are now confirmed by an X-ray single crystal structur e analysis on LaAl: space group Cmcm, Z=8, a=9.455(1) Angstrom, b=7.75 3(1) Angstrom, c=5.791(1) Angstrom, R1/wR2=2.4/5.6, N(F(2)greater than or equal to 2 sigma(I-2))=685, N(var.)=16. The structure of LaAl cont ains zig-zag chains formed by two crystallographically independent Al atoms with alternating angles Al-Al-Al of 64 degrees and 180 degrees. The chains are connected via lanthanum atoms. (C) 1998 Published by El sevier Science S.A. All rights reserved.