“Stagomé” Lattice: The Missing Member of the Star-Kagomé Family

Transition metal-based compounds with new two-dimensional, triangle-based topology are rare but are of considerable interest because of their unusual magnetic properties. Here we report the synthesis of [(CH3)2NH2]2[CoII5(OH)2(HCOO)6(SO4)2]·2H2O with the CoII ions forming a “stagomé” lattice, a previously unknown topology intermediate between an octa-kagomé and a star lattice in terms of number of vertices shared per triangle. Magnetic and heat capacity measurements suggest that the CoII-based compound possesses a canted antiferromagnetic order below 8.7 K. The discovery of the stagomé-lattice compound completes the star-kagomé family of triangle-based lattices.