Synthesis and structure of BxC1-x intercalation compounds with heavy alkali metals (K, Rb, and Cs)

BxC1-x (x = 0.1 and 0.25) oriented platelets were intercalated with alkali metal vapor (M = K, Rb, Cs), giving first-stage M(B0.1C0.9)(8) and M(B0.25C 0.75)(10). The presence of M(BxC1-x)(5) dense domains interstratified in th e first-stage structure were brought out from the 00.l simulations. The pre sence of these domains is attributed to the acceptor electron effect of bor on, which slightly enhances the intercalation rate as compared to pure carb on. Intercalation of Cs in liquid ammonia is improved using 1600 degrees C heat-treated B0.25C0.75 as a host material, and the composition Cs(B0.25C0. 75)(12) is reached after intercalation. In intercalation compounds of Cs in liquid ammonia obtained from heat-treated B0.25C0.75, as the heat-treatmen t temperature (HTT) was increased from 1600 to 2000 degrees C, the segregat ion of first stage was observed in two structures Cs(BxC1-x)(8) and Cs(BxC1 -x)(10) with the respective 2 x 2 0 degrees and 2.23 x 2.23 two-dimensional lattices of the cesium atoms. The presence of these two structures is assi gned to the heterogeneity of the host material induced by the formation of B4C boron carbide domains and the consecutive boron elimination of the BxC1 -x lamellar phase with increasing HTT.