Acta Crystallographica Section B

Structural Science

Volume 55, Part 1 (February 1999)

Acta Cryst. (1999). B55, 35-44 [doi:10.1107/S0108768198007009]

Disorder determined by high-resolution powder diffraction: structure of pentamethylcyclopentadienyllithium

R. E. Dinnebier, M. Schneider, S. van Smaalen, F. Olbrich and U. Behrens

Abstract: The crystal structure of pentamethylcyclopentadienyllithium, [Li(C₁₀H₁₅)] (LiCp*), has been determined from a high-resolution powder pattern by modelling and the maximum entropy method (MEM). The compound crystallizes in space group R3m with lattice parameters a = b = 14.7711 (5), c = 3.82206 (6) Å and V = 722.19 (4) Å³ (Z = 3). LiCp* forms polymeric `multidecker' chains along the c axis. The pentamethylcyclopentadienyl anions are coplanar with each other and show threefold rotational disorder. The MEM calculations did not only confirm the structural model and the type of disorder, but also discovered additional symmetry compared with the Rietveld analysis. This is the first solid-state structure of a Lewis-base-free alkali metal Cp* compound.

Online 1 February 1999


	Rietveld powder data file (CIF format) (411.0 kbytes) Contains datablock rt

	Rietveld powder data file (CIF format) (87.9 kbytes) Contains datablock lt

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