September 2013 issue
Cover illustration: In the compound [Co(C10H15)2]2[CoCl4]·2CH2Cl2, the cobalt atoms exhibit two different oxidation states. The cobaltocenium cation contains cobalt in oxidation state +III. It is located on a twofold rotation axis and has a staggered conformation. The tetrahedral CoCl4 anion has site symmetry -4 and contains cobalt in oxidation state +II. The crystal packing is dominated by C-HCl hydrogen-bonding interactions involving the disordered dichloromethane solvent molecule as donor and the anion as acceptor groups. See: Merola, Ngo & Karpin [Acta Cryst. (2013). E69, m504].