Raman spectrum of Na2SO4 (phases I and II)

Choi, Byoung Kyu; Lockwood, D. J.

doi:10.1016/0038-1098(90)90644-q

Cited by 18 publications

(10 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We consider that this Raman band represents the ν 1 vibration of sulfate in ionic clusters. This vibrational band is close to that of crystalline Na 2 SO 4 phase I (993.5 cm –1 ), the stable solid phase of Na 2 SO 4 at the conditions of our experiments . Note, however, that the experimental temperature–pressure–composition conditions of our experiments are such that precipitation should not occur (i.e., the solution is undersaturated with respect to Na 2 SO 4 ) and other signals of the solid phase are not present in the spectra.…”

Section: Resultssupporting

confidence: 70%

Ion Association in Hydrothermal Sodium Sulfate Solutions Studied by Modulated FT-IR-Raman Spectroscopy and Molecular Dynamics

et al. 2015

View full text Add to dashboard Cite

Saline aqueous solutions at elevated pressures and temperatures play an important role in processes such as supercritical water oxidation (SCWO) and supercritical water gasification (SCWG), as well as in natural geochemical processes in Earth and planetary interiors. Some solutions exhibit a negative temperature coefficient of solubility at high temperatures, thereby leading to salt precipitation with increasing temperature. Using modulated FT-IR Raman spectroscopy and classical molecular dynamics simulations (MD), we studied the solute speciation in solutions of 10 wt % Na2SO4, at conditions close to the saturation limit. Our experiments reveal that ion pairing and cluster formation are favored as solid saturation is approached, and ionic clusters form prior to the precipitation of solid sulfate. The proportion of such clusters increases as the phase boundary is approached either by decreasing pressure or by increasing temperature in the vicinity of the three-phase (vapor-liquid-solid) curve.

show abstract

Section: Resultssupporting

confidence: 70%

Ion Association in Hydrothermal Sodium Sulfate Solutions Studied by Modulated FT-IR-Raman Spectroscopy and Molecular Dynamics

et al. 2015

View full text Add to dashboard Cite

show abstract

“…The Ramanactive sulfate symmetric stretching mode n 1 is observed at 982 cm À1 in dilute solutions 17 and at 994 cm À1 in crystalline Na 2 SO 4 . 51 The corresponding feature (band F in Fig. 3) is observed at lower energies in the IRMPD spectra, in-between 943-959 cm À1 for the quaternary ion complex and 941-945 cm À1 for the ion pair (see ESI †), confirming the previously predicted red-shift of this mode upon ion pair formation, although further solvation of the ion complexes will presumably reduce the red-shift.…”

Section: Discussionsupporting

confidence: 81%

Probing the microsolvation of a quaternary ion complex: gas phase vibrational spectroscopy of (NaSO₄⁻)₂(H₂O)_n=0–6, 8

Wende

Heine

Yacovitch

et al. 2016

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

We report infrared multiple photon dissociation spectra of cryogenically-cooled (NaSO4(-))2(H2O)n dianions (n = 0-6, 8) in the spectral range of the sulfate stretching and bending modes (580-1750 cm(-1)). Characteristic absorption bands and structural trends are identified based on a comparison to harmonic spectra of minimum-energy structures. The bare quarternary complex (NaSO4(-))2 exhibits a C2h structure containing two fourfold-coordinated sodium cations in-between the two chelating sulfate dianions. Its stepwise solvation is driven by an interplay of SO4(2-)-H2O and Na(+)-H2O interactions. The first water binds in a tridentate intersulfate-bridging fashion. The second and third water molecules bind to the sulfate groups at either end of the complex, which is followed by the onset of water hydrogen-bond network formation. In contrast to the binary ion pair, NaSO4(-), no clear evidence for the disruption of the quaternary ion complex upon microhydration is found up to n = 8, underlining its remarkable stability and suggesting that the formation of quaternary ion complexes plays a central role in the initial stages of prenucleation in aqueous Na2SO4 solutions.

show abstract

“…Phase V is the room-temperature phase. The Raman spectra of Na 2 SO 4 phases were intensively studied in early works, and band assignments were made. − Also, the phase transformation was an important subject in the studies reported by Xu and co-workers , investigating the Raman spectra evolution of a single levitated microparticle.…”

Section: Introductionmentioning

confidence: 99%

Raman Spectroscopic Study of Crystallization from Solutions Containing MgSO₄ and Na₂SO₄: Raman Spectra of Double Salts

et al. 2011

View full text Add to dashboard Cite

Mg(2+), Na(+), and SO(4)(2-) are common ions in natural systems, and they are usually found in water bodies. Precipitation processes have great importance in environmental studies because they may be part of complex natural cycles; natural formation of atmospheric particulate matter is just one case. In this work, Na(2)Mg(SO(4))(2)·5H(2)O (konyaite), Na(6)Mg(SO(4))(4) (vanthoffite), and Na(12)Mg(7)(SO(4))(13)·15H(2)O (loeweite) were synthesized and their Raman spectra reported. By slow vaporization (at 20 °C and relative humidity of 60-70%), crystallization experiments were performed within small droplets (diameter ≤ 1-2 mm) of solutions containing MgSO(4) and Na(2)SO(4), and crystal formations were studied by Raman spectroscopy. Crystallization of Na(2)Mg(SO(4))(2)·4H(2)O (bloedite) was observed, and the formation of salt mixtures was confirmed by Raman spectra. Bloedite, konyaite, and loeweite, as well as Na(2)SO(4) and MgSO(4)·6H(2)O, were the components found to occur in different proportions. No crystallization of Na(6)Mg(SO(4))(4) (vanthoffite) was observed under the crystallization condition used in this study.

show abstract

Raman spectrum of Na2SO4 (phases I and II)

Cited by 18 publications

References 15 publications

Ion Association in Hydrothermal Sodium Sulfate Solutions Studied by Modulated FT-IR-Raman Spectroscopy and Molecular Dynamics

Ion Association in Hydrothermal Sodium Sulfate Solutions Studied by Modulated FT-IR-Raman Spectroscopy and Molecular Dynamics

Probing the microsolvation of a quaternary ion complex: gas phase vibrational spectroscopy of (NaSO₄⁻)₂(H₂O)_n=0–6, 8

Raman Spectroscopic Study of Crystallization from Solutions Containing MgSO₄ and Na₂SO₄: Raman Spectra of Double Salts

Contact Info

Product

Resources

About

Raman spectrum of Na2SO4 (phases I and II)

Cited by 18 publications

References 15 publications

Ion Association in Hydrothermal Sodium Sulfate Solutions Studied by Modulated FT-IR-Raman Spectroscopy and Molecular Dynamics

Ion Association in Hydrothermal Sodium Sulfate Solutions Studied by Modulated FT-IR-Raman Spectroscopy and Molecular Dynamics

Probing the microsolvation of a quaternary ion complex: gas phase vibrational spectroscopy of (NaSO4−)2(H2O)n=0–6, 8

Raman Spectroscopic Study of Crystallization from Solutions Containing MgSO4 and Na2SO4: Raman Spectra of Double Salts

Contact Info

Product

Resources

About

Probing the microsolvation of a quaternary ion complex: gas phase vibrational spectroscopy of (NaSO₄⁻)₂(H₂O)_n=0–6, 8

Raman Spectroscopic Study of Crystallization from Solutions Containing MgSO₄ and Na₂SO₄: Raman Spectra of Double Salts