Reflectance spectroscopy of oxalate minerals and relevance to Solar System carbon inventories

Applin, D. M.; Izawa, M. R. M.; Cloutis, E. A.

doi:10.1016/j.icarus.2016.05.005

Cited by 12 publications

(9 citation statements)

References 198 publications

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“…It has also been seen on Vesta, where a specific assignment has not been offered (De Sanctis et al 2012). However, Applin et al (2016) suggest oxalate minerals could explain this band on both Ceres and Vesta. Identifying the specific mineral responsible for this band on Eros will require additional modeling work beyond the scope of this paper.…”

Section: Erosmentioning

confidence: 89%

Evidence for OH or H2O on the surface of 433 Eros and 1036 Ganymed

Rivkin

Howell

Emery

et al. 2018

Icarus

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Section: Erosmentioning

confidence: 89%

Evidence for OH or H2O on the surface of 433 Eros and 1036 Ganymed

Rivkin

Howell

Emery

et al. 2018

Icarus

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“…The identification of oxalate-bearing minerals is extremely important because they are indicators of environmental events [17] and biological activity [16]. The existence of oxalates may serve as a signature of the pre-existence of life, so these compounds are being investigated in the context of possible biological activity on Mars [4,[18][19][20][21][22][23][24][25][26][27][28][29][30]. Oxalic acid and its mineral salts are stable under the pressure and ultraviolet irradiation environment of the surface of Mars [18][19] and, consequently, oxalate minerals could be important in Martian geochemical processes [19].…”

Section: Introductionmentioning

confidence: 99%

Structural, spectroscopic, and thermodynamic characterization of ammonium oxalate monohydrate mineral using theoretical solid-state methods

Colmenero

2019

Journal of Physics and Chemistry of Solids

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In this study, the structural properties, main characteristics of the Raman spectrum, and the thermodynamic properties of the ammonium oxalate monohydrate mineral oxammite, ( 4 ) 2 ( 2 4 ) • 2 , were investigated in theoretical solid-state calculations based on the periodic density functional theory using plane waves and pseudopotentials. The optimized structure of oxammite agreed very well with that obtained from low temperature X-ray diffraction data by structure refinement (orthorhombic symmetry, space group 2 1 2 1 2; lattice parameters: = 8.017 Å; = 10.309 Å; = 3.735 Å). The calculated structural properties, including the lattice parameters, bond lengths and angles, and X-ray powder pattern, accurately reproduced the experimental information. The Raman spectrum determined theoretically agreed with that obtained experimentally. The assignment of the Raman spectral bands significantly improved their previous empirical assignment. Thus, the assignment of a large series of bands was modified and the origins of several previously unassigned bands were found. Five bands in the experimental spectrum at 2344, 2161, 1933, 1902, and 815 −1 , were absent from the computed spectrum and they were identified as combination bands. The band located at 2879 −1 was confirmed as an overtone. Furthermore, the theoretical calculations clearly showed that some features described as single peaks in previous experimental studies were due to the contributions of several bands. The thermodynamic properties of the oxammite mineral, including the specific heats, entropies, enthalpies, and Gibbs free energies, were determined as functions of temperature. The specific heat calculated at 323 K, = 202.3was in good agreement with the corresponding experimental heat capacity, = 211.7where the values only differed by about 4%. Finally, using the computed thermodynamic data, the thermodynamic properties of the formation of oxammite as well as the free energies and reaction constants of the reaction for its thermal decomposition were determined.

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“…These minerals are currently under study to investigate the possible biological activity on Mars [18][19][20][21][22][23][24][25][26][27]. The study of the formation, transport, and concentration of oxalate in the extremely arid zones may provide a geochemical analogue for oxalate-bearing minerals recently suggested to exist on Mars [18].…”

Section: Introductionmentioning

confidence: 99%

“…While there have been no inambiguous detections of specific organic compounds on Mars, meteoritic and cometary material is continuously delivered to the surface of Mars, and oxalic acid is the most abundant dicarboxylic acid in several chondrites [28][29][30]. Based on X-ray diffraction and reflectance spectroscopic analyses, Applin et al [26][27] have shown that solid oxalic acid and its most common mineral salts are stable under the pressure and ultraviolet irradiation environment of the surface of Mars. Therefore, oxalate minerals could be important in numerous Martian geochemical processes, acting as a possible nitrogen sink, and/or contributing to the formation of organic carbonates, methane, and hydroxyl radicals [26].…”

Section: Introductionmentioning

confidence: 99%

Study of the structural, vibrational and thermodynamic properties of natroxalate mineral using density functional theory

Colmenero

Timón

2018

Journal of Solid State Chemistry

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Natroxalate mineral, Na2C2O4, 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 P21/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 -1 , 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 -1 , were not found in the theoretical spectrum. This is because these bands correspond to an overtone, 2ν1 (ν1=875 cm -1 ), and a combination band, ν1+ν2 (ν1,ν2 =875, 481 cm -1 ), 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.

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Reflectance spectroscopy of oxalate minerals and relevance to Solar System carbon inventories

Cited by 12 publications

References 198 publications

Evidence for OH or H2O on the surface of 433 Eros and 1036 Ganymed

Evidence for OH or H2O on the surface of 433 Eros and 1036 Ganymed

Structural, spectroscopic, and thermodynamic characterization of ammonium oxalate monohydrate mineral using theoretical solid-state methods

Study of the structural, vibrational and thermodynamic properties of natroxalate mineral using density functional theory

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