Preparation and spectral assignments of hexadentate chromium(III) complexes containing unsymmetrical edta-type ligands. Trans-(O5) geometrical isomer of sodium (ethylenediamine-N,N,N′-triacetato-N′-3-propionato)chromate(III) trihydrate, trans-(O5)-Na[Cr(ed3ap)]·3H2O and sodium (ethylenediamine-N-diacetato-N′-di-3-propionato)chromate(III) trihydrate, Na[Cr(μ-eddadp)]·3H2O

New hexadentate chromium(III) complexes containing unsymmetrical edta-type ligands, ethylenediamine-N,N,N′-triacetate-N′-3-propionate ion (ed3ap) and ethylenediamine-N-diacetate-N′-di-3-propionate ion (μ-eddadp), have been prepared, chromatographically separated and characterized. Only one [trans-(O5)] of two geometrical isomers of the [Cr(ed3ap)]− complex (1) was isolated. No similar variation is possible for the hexadentate [Cr(μ-eddadp)]− complex (2). I.r. (carboxylate region), deuteron n.m.r., magnetic circular dichroism (m.c.d.) and electronic absorption spectra were used to assign the complexes. Spectral data are discussed by comparison with those of other [Cr(edta-type)]− complexes of known configuration.