Infrared and inelastic neutron scattering study of the 1.03-and 0.95-nm kaolinite-hydrazine intercalation complexes

The interaction of hydrazine with kaolinite was studied using a combination of infrared (IR) spectroscopy, inelastic neutron scattering (INS), and X-r ay powder diffraction. Under ambient temperature and pressure conditions, a nhydrous hydrazine is readily intercalated into the interlamellar region of kaolinite resulting in a kaolinite-hydrazine (KH) intercalation complex wi th a 001 d-spacing of 1.03 nm. Under reduced pressure, the surface loading of hydrazine is reduced to 0.5 hydrazine molecules/unit cell, and the 001 r t-spacing of the KH complex undergoes a partial collapse to a highly ordere d KH complex with a 001 d-spacing of 0.95 nm. This transition from 1.03 to 0.95 nm is accompanied by strong perturbations in the LR and INS, spectra f or vibrational modes of bath the kaolinite and the intercalated hydrazine s pecies. The transition from the 1.03 complex to the 0.95-nm KH complex is m ade possible by the keying of one of the hydrazine amine groups into the si loxane ditrigonal cavity of the kaolinite surface as evidenced by changes o f the IR active stretching and bending modes of the inner OH group. The IR and INS spectra reveal strong hydrogen bonds between the intercalated hydra zine molecules and the kaolinite surface itself. The strongest hydrogen bon ds are intermolecular hydrogen bonds formed between intercalated hydrazine molecules for the 1.03-nm KH complex and are manifested by a strong, broad band at 2975 cm(-1) in the IR spectrum. This band is absent in the IR spect rum of the 0.95 nm KH complex and is replaced by a band at 3270 cm(-1), ind icating a net increase in the distance between Intercalated hydrazine molec ules. Additionally, strong intercalation-induced perturbations occurred for the twist, scissor, asymmetric and symmetric wag modes, and torsional mode s of hydrazine for both the 1.03- and 0.95-nm KH complexes.