Raman spectroscopy of hydrazine-intercalated kaolinite at 77, 298, 323, 343 and 358 K

The Raman spectrum at 298 K of hydrazine-intercalated kaolinite shows a single band at 3620 cm(-1). No other hydroxyl stretching bands are observed. Upon obtaining the spectrum at liquid nitrogen temperature the band is observed at 3616 cm(-1), the same position as for the inner hydroxyl of the non-intercalated kaolinite. Hence this band is assigned to the inner hydroxyl of kaolinite. After exposure to the atmosphere for 10 min and upon obtaining spectra at 77 K, two additional bands are observed at 3607 and 3625 cm(-1). These additional bands are only observed after the onset of deintercalation. The band observed at 3625 cm(-1) is assigned to the inner surface hydroxyls, hydrogen bonded to the hydrazine. The fact that the band is only observed after the onset of deintercalation suggests that the band is Raman inactive and infrared active. Raman spectroscopic analysis indicates that there are two types of hydrazine molecules as evidenced by two NH bands, (a) weakly hydrogen bonded as evidenced by two bands observed around 3300 and 3312 cm(-1) and (b) a strongly hydrogen-bonded hydrazine as evidenced by bands at 2890 and 2948 cm(-1). The two NH symmetric stretching bands at around 3300 and 3312 cm(-1) combined with the two NH antisymmetric stretching bands at 3361 and 3367 cm(-1) suggest that there are two slightly different NH2 units in the hydrazine-intercalated complex. Copyright (C) 2002 John Wiley Sons, Ltd.