Raman spectroscopy of dawsonite NaAl(CO₃)(OH)₂

Abstract

Raman spectroscopy at both 298 and 77 K complimented with infrared spectroscopy has been used to study the structure of dawsonite. Previous crystallographic studies concluded that the structure of dawsonite was a simple one, however both Raman and infrared spectroscopy show that this conclusion is incorrect. Multiple bands are observed in both the Raman and infrared spectra in the antisymmetric stretching and bending regions showing that the symmetry of the carbonate anion is reduced and in all probablity the carbonate anions are not equivalent in the dawsonite structure. Multiple OH deformation vibrations centred upon 950 cm -1 in both the Raman and infrared spectra show that the OH units in the dawsonite structure are non-equivalent. Calculations using the position of the Raman and infrared OH stretching vibrations enabled estimates of the hydrogen bond distances of 0.2735, 0.27219 pm at 298 K and 0.27315, 0.2713 pm at 77 K to be made. This indicates strong hydrogen bonding of the OH units in the dawsonite structure.

Thermo‐Raman spectroscopy of synthetic nesquehonite — implication for the geosequestration of greenhouse gases

“…21,23,27,31,42,55,56 It is important to understand the spectroscopy of the carbonate ion. The free ion CO 3 2 with D 3h symmetry exhibits four normal vibrational modes: a symmetric stretching vibration ( 1 ), an out-of-plane bend ( 2 ), a doubly degenerate asymmetric stretch ( 3 ) and another doubly degenerate bending mode ( 4 ).…”

Corrosion Resistance Properties of Aluminum Coating Applied by Arc Thermal Metal Spray in SAE J2334 Solution with Exposure Periods

“…The different phases are observed at different Raman shift, i.e., 570 cm´1 (Gibbsite) [58], 868 cm´1 (Bayerite) [58], 662 cm´1, 1405 cm´1 and 1525 cm´1 (Dawsonite) [59]. The intensity of the Raman spectra is weak due to the very low concentrations of phases and film thickness being very low.…”

Raman spectroscopic study of the tellurite minerals: Carlfriesite and spiroffite

“…• Author to whom correspondence should be addressed (r.frost@qut.edu.au) 2 A 2 (XO 3 ) 3 .xH 2 Raman spectroscopy has proven very useful for the study of minerals [25][26][27][28][29][30][31][32][33][34][35].…”