Graphite-MnCll-AK& intercalation compounds have been prepared via MnClz-AI& complexes. First stage compounds are eventually formed at both 325 and 500Β°C; products formed at the lower reaction temperature are richer in Mn (C~.~M~CI*(AICI,)~.~I) than those at 500" (C7,l~MnCl2(AICl2 &I,). At 325" the mechanism is a quasi-selective intercalation of AiCI~ to the second stage followed by insertion of MnC12 to a mixed stage I compound, and finally an isostage Mn enrichment with Al depletion. At 500". insertion proceeds differently. Rate limiting reactions at each temperature are proposed.
Powder X-ray diffractograms give Z, = 9.51 a for Mn-rich first stage compounds. Comparison of calculated and observed (001) structure factors gives an Mn-Cl spacing of 1.46A as in the pure dichloride. Analysis of (h/d) positions and the ( 101) and (Ill)_ intensities of the inserted MnCI: indicate an intercalant superlattice with a0 = 3.69 A and co = 3 x I, = 28.53 A. First stage compounds prepared at 500" are considerably less ordered.
Results obtained at 325" are especially significant in that (I) this represents the lowest temperature at which dichlorides have been intercalated to rich stages, and (2) long-range (i.e. 3-dimensional) ordering has been documented in a dichloride intercalation compound for the first time, and is sensitive to reaction temperature.