Chemical Excision of Tetrahedral FeSe2 Chains from the Superconductor FeSe: Synthesis, Crystal Structure, and Magnetism of Fe3Se4(en)2.

Shiny black needle-like crystals of Fe3Se4(en)2 are solvothermally synthesized from a mixture of elemental Fe and Se, en, and NH4Cl as a mineralizer (autoclave, 773 K, 5 d).