2024-03-28T20:13:01Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/2081902020-12-12T16:48:53Zcom_10261_135com_10261_4col_10261_388
Study of the structural, vibrational and thermodynamic properties of natroxalate mineral using density functional theory
Colmenero, Francisco
Timón, Vicente
Ministerio de Economía y Competitividad (España)
Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (España)
CSIC - Centro Técnico de Informática (CTI)
Consejo Superior de Investigaciones Científicas (España)
Centro de Supercomputación de Galicia
Organic minerals
Oxalates
Natroxalate
DFT
Raman Spectroscopy
Thermodynamic Properties
10 pags., 8 figs., 9 tabs.
Natroxalate mineral, NaCO, is a fundamental oxalate mineral widespread in nature, present in humans, animals and plants, as well as in naturally occurring minerals. The characterization of oxalate minerals is extraordinarily important since these organic minerals are indicators of environmental events and of the presence of biological activity, because they are commonly of biological origin. These minerals are currently under study to investigate the possible biological activity on Mars. The identification of these compounds is usually performed by X-ray diffraction and Raman spectroscopy. Theoretical calculations are of great value for the study and interpretation of the results of these experimental techniques. In this work, natroxalate mineral structure and Raman spectrum was studied by first principle calculations based on the density functional theory. The computed structure of natroxalate reproduces the one determined experimentally by X-ray diffraction (monoclinic symmetry, space group P2/c; lattice parameters a = 3.449 Å, b = 5.243 Å; c = 10.375 Å). Lattice parameters, bond lengths, bond angles and X-ray powder pattern were found to be in very good agreement with their experimental counterparts. Raman spectrum was then computed by means of density functional perturbation theory and compared with the experimental spectrum. Since the results were also found in agreement with the experimental data, a normal mode analysis of the theoretical spectra was carried out and used in order to assign the main bands of the Raman spectrum. The band found at about 567 cm, described as a single peak in previous experimental works, is shown clearly to have two contributing bands. Finally, two bands of the observed spectrum, located at the wavenumbers 1750 and 1358 cm, were not found in the theoretical spectrum. This is because these bands correspond to an overtone, 2ν (ν = 875 cm), and a combination band, ν + ν (ν,ν = 875, 481 cm), respectively. Finally, the fundamental thermodynamic properties of natroxalate mineral were determined. The calculated specific heat at 298.15 K is in excellent agreement with the experimental value, the difference being less than 1%. Since for most of these properties there are not experimental values to compare with, their values were predicted.
2020-04-19T16:16:14Z
2020-04-19T16:16:14Z
2018-04-22
2020-04-19T16:16:14Z
artículo
Journal of Solid State Chemistry 263: 131-140 (2018)
http://hdl.handle.net/10261/208190
10.1016/j.jssc.2018.04.022
http://dx.doi.org/10.13039/501100009613
http://dx.doi.org/10.13039/501100003339
http://dx.doi.org/10.13039/501100003329
Postprint
http://dx.doi.org/10.1016/j.jssc.2018.04.022
Sí
info:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/FIS2013–48087-C2-1-P
openAccess
Academic Press