cis-and trans-Diisothiocyanato(1,4,8,11-tetraazacyclotetradecane)chromium(III) Perchlorate

The cis isomer of the title compound, [Cr(NCS)₂(C₁₀H₂₄N₄)](ClO₄), is a racemate of the Bosnich type V structure; the trans complex is a meso substance with a Bosnich type III stereochemistry. There is no appreciable change in the structures of the title compound on cooling, even though there are marked color changes. The Cr-N bond lengths are all in the range 1.983 (2)-1.998 (4) Å for the bonds to the isothiocyanate groups and in the range 2.046 (2)-2.088 (3) Å for the bonds to cyclam N atoms.