The molecule of bis[1,2-dicarba-3-cobalta-closo-dodecaborane(II)], [Co
(C7H26B18NO2)], comprises two dicarbaborane ligands coordinated to the
Co atom to form a 'sandwich' compound linked by pentagonal faces. The
ligands are also linked by a monoatomic nitrogen bridge to which a me
thoxycarbonylmethyl group is bound, B-N bond lengths being 1.577 (4) a
nd 1.563 (4) angstrom.