title: Infrared spectroscopic study of natural hydrotalcites carrboydite and hydrohonessite.
abstract: Infrared spectroscopy has proven most useful for the study of anions in the interlayer of natural hydrotalcites. A suite of naturally occurring hydrotalcites including carrboydite, hydrohonessite, reevesite, motukoreaite and takovite were analysed. Variation in the hydroxyl stretching region was observed and the band profile is a continuum of states resulting from the OH stretching of the hydroxyl and water units. Infrared spectroscopy identifies some isomorphic substitution of sulphate for carbonate through an anion exchange mechanism for the minerals carrboydite and hydrohonessite. The infrared spectra of the CO3 and SO4 stretching region of takovite is complex because of band overlap. For this mineral some sulphate has replaced the carbonate in the structure. In the spectra of takovites, a band is observed at 1346 cm(-1) and is attributed to the carbonate anion hydrogen bonded to water in the interlayer. Infrared spectroscopy has proven most useful for the study of the interlayer structure of these natural hydrotalcites.
authors: Centre for Instrumental and Developmental Chemistry, Queensland University of Technology, GPO Box 2434, Brisbane Qld 4001, Australia. r.frost@qut.edu.au
authors: Ray L
authors: RL
authors: Frost
authors: Matt L
authors: ML
authors: Weier
authors: Meagan E
authors: ME
authors: Clissold
authors: Peter A
authors: PA
authors: Williams
mesh_terms: D000536:Aluminum Hydroxide / Q000737:chemistry*; D002254:Carbonates / Q000737:chemistry; D008276:Magnesium Hydroxide / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013431:Sulfates / Q000737:chemistry; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D002254:Carbonates; D013431:Sulfates; D014867:Water; C010467:hydrotalcite; D000536:Aluminum Hydroxide; D008276:Magnesium Hydroxide