Crystal structure of a cyanide-bridged heptanuclear manganese(III)–chromium(III) complex with a ground state S = 21/2

K3[Cr(CN)6] reacts with the mononuclear MnIII complex Mn(salen)ClO4 · 2H2O [salen: N,N′-ethylenebis(salicylideneiminato)dianion] to give a bimetallic heptanuclear complex cation salt [Cr{(CN)Mn(salen · H2O)}6][Cr(CN)6]6H2O. In the complex anion, [Cr{(CN)Mn(salen · H2O)}6]3+, six MnIII ions coordinate to a CrIII center via cyano bridges, forming a spherical species with 3 symmetry. A study of magnetic properties shows the presence of antiferromagnetic interaction through the cyanide bridge between CrIII (S = 3/2) and MnIII (S = 4/2) and results in a ground state S = 21/2.