R. Pottgen et al., PREPARATION, STRUCTURE REFINEMENT, AND PROPERTIES OF SOME COMPOUNDS WITH DY2FE2SI2C- AND LAMN11C2-X TYPE-STRUCTURE, Journal of solid state chemistry, 114(1), 1995, pp. 66-72
The new compounds Tm2Fe2Si2C and Lu2Fe2Si2C were prepared by arc-melti
ng cold-pressed pellets of the elemental components. They crystallize
with the monoclinic Dy2Fe2Si2C-type structure. The crystal structure o
f Tm2Fe2Si2C was refined from single-crystal X-ray data: C2/m, a = 104
9.7(3) pm, b = 388.2(1) pm, c = 664.6(2) pm, beta = 128.96(2)degrees,
R = 0.020 for 296 structure factors, and 21 variable parameters. The s
tructure may be considered as consisting of two-dimensionally infinite
polyanionic layers of [Fe2Si2C6-](n) separated by the rare-earth cati
ons. The hydrolysis of Er2Fe2Si2C with diluted hydrochloric acid yield
s mainly methane besides about 20 wt% of C-2 and C-3 hydrocarbons. Tm2
Fe2Si2C orders antiferromagnetically at T-N = 2.7(2) K. The magnetizat
ion behavior for this compound suggests metamagnetism. Lu2Fe2Si2C is P
auli paramagnetic. Electrical conductivity measurements of polycrystal
line samples of Tm2Fe2Si2C and Lu2Fe2Si2C indicate metallic conductivi
ty. ThFe10SiC2-x has a tetragonal LaMn11C2-x. type structure with the
lattice constants a = 1005.3(2) pm and c = 651.6(2) pm. (C) 1995 Acade
mic Press, Inc.