An intermetallic molecular nanomagnet with the lanthanide coordinated only by transition metals.

Magnetic molecules known as molecular nanomagnets (MNMs) may be the key to ultra-high density data storage. Thus, novel strategies on how to design MNMs are desirable. Here, inspired by the hexagonal structure of the hardest intermetallic magnet SmCo 5 , we have synthesized a nanomagnetic molecule where the central lanthanide (Ln) Er III is coordinated solely by three transition metal ions (TM) in a perfectly trigonal planar fashion. This intermetallic molecule [Er III (Re I Cp 2 ) 3 ] (ErRe 3 ) starts a family of molecular nanomagnets (MNM) with unsupported Ln-TM bonds and paves the way towards molecular intermetallics with strong direct magnetic exchange interactions-a promising route towards high-performance single-molecule magnets.