An X-ray diffraction study of oriented lithium-N,N,N',N'-tetramethyl- ethane-1,2-diamine intercalated graphite

The intercalation of N,N,N',N'-tetramethyl-ethane-1,2-diamine (tmeda) into C₆Li derived from papyex, a partially oriented graphite foil, results in the co-presence of two ternary phases having out-of-plane (c-axis) identity periods of 11.5 and 9.1 Å. As we reported for the powdered sample prepared using a natural graphite source, these distances are associated with two tmeda orientations. The tmeda orientation had no significant effect on the in-plane lattice. The orientated texture of the sample gave in-plane (a-b plane) unit cell dimension, a = 4.3 Å, close to the √3a_o distance of the stage I C₆Li precursor unit cell and allowed changes in the in-plane packing to be detected by extending the reflux time of the reaction between C₆Li and tmeda or by using the stage II binary C ₁₂Li as the precursor. An expansion of the in-plane lattice spacing to 4.6 Å occurred for part of the sample. The ideal stoichiometry of the unexpanded ternary compound based on the unit cell volume and having the maximum number of tmeda molecules within the P6/mmm unit cell was estimated to be C₆Li (tmeda)₁. However, a structure factor analysis indicated that tmeda occupancy within the unit cell is fractional.