[Li 6 (C 2 N 2 H 8 ) 11.5 ][Fe 4 Se 8 ]: the first lithium-containing chalcogenidotetraferrate synthesized in solution

The octaselenidotetraferrate(II/III) with six Li atoms as counter-ions chelated by ethylenediamine (en, C 2 H 8 N 2 ), {[Li 6 (en) 11.5 ][Fe 4 Se 8 ]} n , was synthesized from Li, FeSe and Se in an ethylenediamine solution at room temperature. Its crystal structure was determined at 100 K and has triclinic ( P \overline{1}) symmetry. The [Fe 4 Se 8 ] 6− anions show a connectivity comparable to a distorted tetrahedral cluster structure. Contact distances are given, and central structure features compared to literature known selenidoferrates with the same anion motif.