Alkali metal intercalation in layer structured α-HfNBr☆ Original Research Article

The layer structured α-HfNBr is isotypic with FeOCl, and forms a Li intercalated compound by the reaction with n-butyllithium. The lithiated compound was swelled with tetrahydrofuran (THF), increasing the basal spacing from 8.6 to 17.3 Å. Similar alkali metal and THF co-intercalated compounds could be prepared by a one-step reaction with Li and Na naphthalene solutions in THF. X-ray structural study showed that the two-dimensional structure of the host crystal was maintained after the swelling with THF. On Li intercalation the non-magnetic α-HfNBr was changed into a paramagnetic compound having localized electron spins down to 2 K.