Raman Microprobe Spectroscopy of Halloysite

R.L. Frost and H.F. Shurvell
Centre for Instrumental and Developmental Chemistry, Queensland University of Technology, Brisbane, Q 4001, Australia
Permanent address: Department of Chemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6.

Abstract: The Raman spectra of a tubular halloysite originating from Matauri Bay, New Zealand, have been obtained using a Renishaw 1000 Raman microscope system. The Raman microprobe enables the Raman spectra of crystals as small as 0.8 µm diameter to be obtained over the complete wavelength range and allows spectral variations along the different crystal axes to be studied. Three bands in the hydroxyl stretching region were observed at 3616.5, 3623.4 and 3629.7 cm−1 and are attributed to the inner hydroxyls of the shared lower plane of the octahedral sheet of the halloysite. Two bands at 3698.2 and 3705 cm−1 were obtained for the outer hydroxyls of the unshared outer octahedral plane. The relative intensity of the 3629.7 cm−1 band varied according to the tube orientation. Lattice vibrations of the halloysite were also found to be orientation-dependent.

Key Words: Halloysite • Kaolinite • Lattice Vibrations • Raman Microprobe • Raman Spectroscopy

Clays and Clay Minerals; February 1997 v. 45; no. 1; p. 68-72; DOI: 10.1346/CCMN.1997.0450107
© 1997, The Clay Minerals Society
Clay Minerals Society (www.clays.org)