Although the term "single-molecule magnet" was first employed in 1996, the first single-molecule magnet, [Mn 12 O 12 (OAc) 16 (H 2 O) 4 ] (nicknamed "Mn 12 ") was reported in 1991. This manganese oxide compound features a central Mn(IV) 4 O 4 cube surrounded by a ring of 8 Mn(III) units connected through bridging oxo ligands, and displays slow magnetic relaxation behavior up to temperatures of ca. 4 K.