Beschreibung:
<jats:p>The title compounds were prepared by arc-melting of the elemental components and subsequent annealing. Their crystal structure is hexagonal P 6̅ 2 m with one formula unit per cell. It was determined from single-crystal X-ray data of La<jats:sub>12</jats:sub>Re<jats:sub>5</jats:sub>C<jats:sub>15</jats:sub> (a =1116.8(1) pm, c =545.3(1) pm, R = 0.060 for 287 structure factors and 27 variable parameters) and Ho<jats:sub>12</jats:sub>Re<jats:sub>5</jats:sub>C<jats:sub>15 </jats:sub>(ia = 1066.7(1) pm, c = 504.2(1) pm, R = 0.018 for 392 F's and 31 variables). The structures correspond to the formula Ln<jats:sub>12</jats:sub>[ReC<jats:sub>3</jats:sub>]2[Re<jats:sub>3</jats:sub>C<jats:sub>3</jats:sub>(C<jats:sub>2</jats:sub>)<jats:sub>3</jats:sub>],where the brackets indicate two different trigonal planar anionic rhenium-carbon groups. The coordination of the rhenium atoms in these polyanions seems to be compatible with the 18-electron rule. </jats:p>