Intercalation of primary monoamines in the lamellar protonic oxide HNb 3 O 8 · H 2 O

The intercalation of alkyl monoamines in the protonic oxide HNb 3 O 8 · H 2 O is quantitative for the amines NH 2 C n H 2n+1 with n ranging from 1 to 9. The intercalated oxide NH 3 CH 3 Nb 3 O 8 is anhydrous at room temperature whereas monohydrates NH 3 C n H 2n+1 NbO 3 · H 8 O 2 are the stable form at room temperature; these latter oxides can be dehydrated into the oxides NH 3 C n H 2n+1 Nb 3 O 8 without any destruction of the structure, their zeolithic character is observed. The structural evolution of these compounds is interpreted in terms of a transversal orientation of the amine chains with respect to the [Nb 3 O 8 ] − layers and compared to the one of the N 3 HC n H 2n+1 TiNbO 5 oxides.