Next Article in Journal
Non-Parametric Reconstruction of Cosmological Observables Using Gaussian Processes Regression
Previous Article in Journal
Some Addition Theorems for Spin-Weighted Spherical Harmonics
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Universe
Volume 10
Issue 12
10.3390/universe10120462
universe-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Raman, MIR, VNIR, and LIBS Spectra of Szomolnokite, Rozenite, and Melanterite: Martian Implications

by
Xiai Zhuo
,
Ruize Zhang
,
Erbin Shi
*,
Jiahui Liu
and
Zongcheng Ling
Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Technology, Institute of Space Sciences, Shandong University, Weihai 264209, China
*
Author to whom correspondence should be addressed.
Universe 2024, 10(12), 462; https://doi.org/10.3390/universe10120462
Submission received: 9 November 2024 / Revised: 12 December 2024 / Accepted: 17 December 2024 / Published: 19 December 2024
(This article belongs to the Section Planetary Sciences)
Browse Figures
Versions Notes

Abstract

:
Different sulfates (Ca-, Mg, and Fe- sulfates) have been extensively detected on the Martian surface. As one of the Martian sulfates, the presence of ferrous sulfates will provide valuable clues about the redox environment, hydrological processes, and climatic history of ancient Mars. In this study, three hydrated ferrous sulfates were prepared in the laboratory by heating dehydration reactions. These samples were analyzed using X-ray Diffraction (XRD) to confirm their phase and homogeneity. Subsequently, Raman, mid-infrared (MIR) spectra, visible near-infrared (VNIR) spectra, and laser-induced breakdown spectroscopy (LIBS) were measured and analyzed. The results demonstrate that the spectra of three hydrated ferrous sulfates exhibit distinctive features (e.g., the v1 and v3 features of S O 4 2 − tetrahedra in their Raman and MIR spectra) that can offer new insights for identifying different ferrous sulfates on Mars and aid in the interpretation of in-situ data collected by instruments such as the Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC), SuperCam, and ChemCam, etc.

1. Introduction

In recent years, as humanity’s exploration of Mars has advanced, scientists have discovered various secondary minerals on the Martian surface and subsurface [1,2,3,4], among which the presence of sulfates has attracted significant attention [4,5,6,7,8,9,10]. The discovery of sulfates not only provides valuable insights into the past environmental conditions of Mars but also offers new perspectives for future Mars exploration missions and resource utilization [11]. Through the analysis of data from Mars rovers and orbiters, scientists have been identified different sulfate minerals at multiple locations on Mars, such as the Meridiani Planum near the equator [12], Gale Crater [13], Jezero Carter [14], and the northern polar region [15], etc. These sulfate minerals, including calcium sulfates (gypsum, anhydrite) [16,17,18], magnesium sulfates (kieserite) [6,19], and iron sulfates (jarosite, FeOHSO4) [20,21,22,23,24,25] indicate that Mars once had liquid water and underwent complex geological and chemical evolution.
Among the various sulfate minerals, ferrous sulfate presents a particularly intriguing subject. On Earth, ferrous sulfates are found in oxidation zones of iron-bearing ore beds, e.g., pyrite, marcasite, chalcopyrite, etc. [26]. They are also found in related environments, like coal fire sites [27]. Studying the potential existence and formation mechanisms of ferrous sulfate on Mars could reveal critical information about the Martian surface and subsurface chemical environments, and offer scientific foundations for future resource development on Mars. Using data collected by instruments aboard the Mars rovers and orbiters, scientists have identified spectral signatures and mineralogical evidence that suggest the presence of ferrous sulfate in some Martian regions. For example, Bishop et al. in 2009 [28] conducted a detailed analysis of the light-toned, sulfate-rich layered deposits in Juventae Chasma. They discovered that the Vis-NIR spectral characteristics of the polyhydrated sulfate outcrops most closely align with those of ferricopiapite, melanterite (FeSO4·7H2O), or starkeyite (MgSO4·4H2O). Szomolnokite and jarosite have been found as distinct layers within polyhydrated non-Fe sulfate at Columbus Crater [29]. Jarosite, rozenite (FeSO4·4H2O), and szomolnokite (FeSO4·H2O) have been proposed to exist on Mars by OMEGA and CRISM [29,30]. These findings imply that Mars once had conditions favorable for the formation of ferrous sulfate, such as acidic and habitable environments with the presence of liquid water [29,30,31,32]. The identification of ferrous sulfate not only enriches our understanding of the planet’s past aqueous history but also provides new insights into the redox conditions and chemical processes that have shaped the Martian surface.
Although there is potential evidence suggesting the existence of ferrous sulfate on Mars, confirming its presence remains challenging due to the lack of a comprehensive spectral database for ferrous sulfates. Current spectroscopic data from Mars rovers and orbiters hint at the possible presence of this mineral, but without detailed and specific spectral signatures for ferrous sulfates, it is difficult to definitively identify it. The absence of such a database complicates the interpretation of remote sensing data, making it challenging to distinguish ferrous sulfate from other iron-bearing minerals. Consequently, further laboratory studies and the development of an extensive spectral library for ferrous sulfate are essential to determine its occurrence and distribution on the Martian surface accurately.
The goal of this study is to obtain the spectral features of three hydrated ferrous sulfates (szomolnokite, rozenite, and melanterite). By doing so, we aim to develop a comprehensive spectral database that can facilitate the identification of these minerals on Mars and Earth. This database will serve as a critical tool for interpreting remote sensing data from Mars rovers and orbiters, helping scientists to accurately detect and differentiate ferrous sulfates on the Martian surface. Through this research, we hope to enhance our understanding of the mineralogical composition of Mars and provide valuable resources for future exploration missions.

2. Materials and Methods

This section presents the materials, methods, and instruments used in the synthesis and characterization of hydrated ferrous sulfates, including melanterite (FeSO4·7H2O), szomolnokite (FeSO4·H2O), and rozenite (FeSO4·4H2O), with a focus on various spectroscopic techniques for mineral analysis. First, the chemical reagents and synthesis methods are described; Then, the instruments employed for phase identification and spectroscopic analysis, such as X-ray powder diffraction (XRD), Raman spectroscopy, mid-infrared (MIR) spectroscopy, visible near-infrared (VNIR) spectroscopy, and laser-induced breakdown spectroscopy (LIBS), are introduced in detail. Each technique’s parameters and operational conditions are outlined to provide a comprehensive understanding of the experimental procedures.

2.1. Chemical Reagents

The FeSO4·7H2O (AR, ≥99%) was purchased from the Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China).

2.2. Synthesis of Three Hydrated Ferrous Sulfates

The melanterite (FeSO4⋅7H2O) was synthesized by recrystallizing the raw materials at room temperature. The recrystallized melanterite was ground to run the different spectroscopy measurements and as raw materials to synthesize szomolnokite (FeSO4·H2O) and rozenite (FeSO4·4H2O) at different temperatures. The rozenite was synthesized by heating the ground melanterite at 50 °C for 24 h and the szomolnokite was synthesized by heating the ground melanterite at 75 °C for 24 h.

2.3. Instruments

2.3.1. X-Ray Powder Diffraction (XRD)

Mineral phases of the synthetic samples were confirmed by using XRD measurements conducted using a Rigaku Ultima IV with CuKα radiation (λ = 1.54052 Å) at 40 kV and 40 mA, with a 0.02° increment. The range of 2 theta covered from 5° to 70°, with data collected at a rate of 5° per minute.

2.3.2. Raman Spectroscopy

An inVia® Raman imaging system (Renishaw Company in Gloucestershire, UK) was used, which uses a 532-nm line of a DPSS laser for excitation, and a long working distance 50× objective (NA = 0.75) for signal collection. The Raman spectra from 100 to 4000 cm−1 were collected for all synthesized samples. The inVia system has a spectral resolution better than 1 cm−1 and a spectral repeatability of ± 0.2 cm−1. The spectral wavelength was initially calibrated using the emission lines of the Ne lamp. The Raman peak position of a Si wafer (520.7 cm−1) was checked and corrected on inVia at the beginning and the end of every working day. These two calibrations ensure a Raman peak position accuracy of ±0.2 cm−1 in this study.

2.3.3. Mid-Infrared (MIR) Spectroscopy

The Bruker vertex 70 Fourier Transform infrared Spectrometer of Shandong University in Weihai has been used to obtain the MIR spectra of samples in the range of 4000–400 cm−1 with 32 scans. The Spectral resolution is better than 0.16 cm−1 with signal-to-noise ratio is 45,000: 1. To measure the MIR transmission spectrum, we chose the HF-12 tablet mold. The KBr and sample were mixed at a mass ratio of 100:1, then grind the mixture. Finally, the ground mixture was put into the HF-12 tablet mold and pressed by the tablet press at 12–13 MPa for 2 minutes.

2.3.4. Visible Near-Infrared (VNIR) Spectroscopy

The FiledSpec4 Hi-Res VNIR Spec-Meter (Analytical spec Devices (ASD), Inc. in Malvern, UK) of Shandong University in Weihai has been used to obtain the VNIR spectra of samples in the range of 350–2500 nm. The spectrum has a resolution of 3 nm in the range of 350–1000 nm and 8 nm in the range of 1000–2500 nm. Prior to measurement, the spectrometer was calibrated using Lambert surface (SRS-99-010) from Labsphere® in North Sutton, NH, USA.

2.3.5. Laser-Induced Breakdown Spectroscopy (LIBS) MIR

Laser-induced breakdown spectroscopy (LIBS) initiated by laser ablation of the samples in a vacuum chamber with the simulated atmospheric environment of Mars (CO2, ~7 mbar) and Earth environment, respectively, at Shandong University, Weihai. The system has been equipped with a Q-switched pulsed Nd: YAG laser with a power of 200 mJ and a wavelength of 1064 nm. The corresponding laser fluence was about 83.56 J/cm2, and the average diameter of the laser-focused spot size on the sample was 400 μm. The synthesized ferrous sulfate samples were pressed under a pressure of ~20 MPa for 90 s to form a pellet with a diameter of 1 cm. Three spectra were collected at different locations for each sample, and different laser energies were used. Three spectra were collected for every sample and every spectroscopy of them was acquired by an accumulation of twelve shots.

3. Results

3.1. The Crystal Structure of Three Hydrated Ferrous Sulfates

Szomolnokite crystallizes in the triclinic system, specifically in the space group P1, with lattice parameters approximately a = 5.18 Å, b = 5.18 Å, c = 7.61 Å, α = 107.57° and β = 112.2°, and γ = 93.65° (Figure 1a) [33]. The iron (Fe) ion in szomolnokite is coordinated by five oxygen atoms from sulfate groups and one water molecule, forming a distorted octahedral geometry. The sulfate (SO4) groups are tetrahedrally coordinated, with sulfur in the center and oxygen atoms at the corners. The single water molecule is integrated into the crystal structure, forming hydrogen bonds with the sulfate groups and contributing to the overall stability of the mineral. The hydrogen bonding network between the water molecule and the sulfate groups is essential for maintaining the structural integrity of szomolnokite.
Rozenite crystallizes in the monoclinic system, specifically in the space group P21/n, with lattice parameters approximately a = 5.97 Å, b = 13.64 Å, c = 10.98 Å, and β = 94.43° (Figure 1b) [34]. The iron (Fe) ion in rozenite is coordinated by four water molecules, forming a distorted octahedral arrangement with the tetrahedrally coordinated sulfate (SO4) groups. The four water molecules are crucial to the structure, forming hydrogen bonds with the sulfate groups and contributing to the stability of the crystal. This hydrogen bonding network is essential for maintaining the structural integrity of rozenite.
Melanterite is a mineral composed of hydrated iron sulfate with the chemical formula FeSO4⋅7H2O (Figure 1c). The crystal structure of melanterite is monoclinic, belonging to the space group P21/c, with lattice parameters approximately a = 14.07 Å, b = 6.50 Å, c = 11.04 Å, and β = 105.6° [35]. The crystal structure of melanterite is formed by a SO4 tetrahedron, two independent M(H2O)6 octahedra (M = Fe1 and Fe2), and one interstitial H2O group which is not directly bonded to Fe2+ cations. Fourteen H-bonds occur, connecting Fe2+ centered octahedra to the SO4 tetrahedra, giving rise to an undulating layer showing the alternation [36,37].

3.2. XRD

The XRD patterns measured by three hydrated ferrous sulfates are presented in Figure 2. Initial phase identification for these samples was performed using XRD. By comparing the positions of all prominent peaks, the diffraction patterns of the samples were found to align well with the standard data. The standard data in Figure 2 were produced by their cif files that were converted to XRD pattern in software Mercury 3.6. These results confirm that the synthesized samples are pure and homogeneous, allowing us to proceed with further spectroscopic analysis of these pure samples.

3.3. Raman

The Raman spectra of three hydrated ferrous sulfates were measured in the range of 100 to 4000 cm−1 (Figure 3; Table 1). These spectra reveal the fundamental vibrational modes of the molecules. In the region from 100 to 1300 cm−1, the vibrational characteristics of the synthesized samples indicate the influence of S O 4 2 − tetrahedra, including symmetric stretching (ν1), antisymmetric stretching (ν3), symmetric bending (ν2), and antisymmetric bending (ν4) modes, respectively [11,38]. The features around 1600 cm−1 and in the range of 3200 to 3600 cm−1 are attributed to the O-H bending and stretching modes of structural H2O, respectively. The modes of structural H2O include symmetric stretching (ν1), antisymmetric stretching (ν3), and bending (ν2) [11,38]. Table 1 summarizes the Raman features and their assignments for the three hydrated ferrous sulfates. The three hydrated ferrous sulfates have their unique features which indicate that Raman spectroscopy can be used to distinguish them on Mars and Earth from different minerals.

3.4. MIR

The MIR spectra were acquired to complement the Raman spectra and to identify the MIR vibrational modes of three hydrated ferrous sulfates. The peak positions and assignments for the three samples are detailed in Table 2, and their MIR spectra are shown in Figure 4. Generally, while the MIR peak positions are similar to those of the Raman peaks, MIR peaks are relatively broader. The MIR spectra primarily feature bands in the ranges of 400–1350 cm−1, 1500–2000 cm−1, and 3000–4000 cm−1. The 350–1350 cm−1 range corresponds to the vibrational features of the S O 4 2 − tetrahedra, whereas the 1500–2000 cm−1 and 3000–4000 cm−1 ranges are associated with the H2O modes [11,39]. Similar to Raman spectra, three hydrated ferrous sulfates also have distinct MIR features, which means the MIR features of three hydrated ferrous sulfates can also be used to identify them in different environments.

3.5. VNIR

The VNIR spectra of three hydrated ferrous sulfates, ranging from 350 to 2500 nm, were analyzed to explore the overtone and combinational vibrational modes of H2O, OH−, Fe2+, and S O 4 2 − ionic groups, the data presented in Figure 5. The VNIR spectra of the three hydrated ferrous sulfates in this study are comparable to those of other hydrated sulfates, such as hydrated ferric sulfates. Bands in the 1.4 to 2.0 μm range are attributed to combinations of H2O and OH− bending, as well as translations or rotations, while bands in the 2.1 to 2.5 μm range are ascribed to combinations of H2O, OH−, and overtones of S-O bending [39]. Strong absorption peaks around 1.9 μm nm in all three hydrated ferrous sulfates are likely due to a combination of OH stretching and water bending modes. The peak around 2.4 μm results from the combination of S O 4 2 − tetrahedron stretching and water bending modes [11]. Many Fe (II) sulfates exhibit a sharp but weak band near 0.43 μm due to the 5T2g to 3T2g electronic excitation transition [39,40]. An additional electronic band occurs near 0.5 Fe(II) sulfates spectra due to the 5T2g to 1A1g transition [39,40,41]. The Fe2+ crystal field band occurs at longer wavelengths, near 0.9–1.2 μm [39]. The Fe2+ electronic excitation bands are centered near 0.94 and 1.33 μm in the spectrum of szomolnokite which agree with 0.93 and 1.31 μm in a szomolnokite spectrum analyzed by Crowley et al. in 2003 [40]. Detailed assignments of the absorption bands are listed in Table 3.

3.6. LIBS

The LIBS spectra of three hydrated ferrous sulfates were measured under both Earth and simulated Mars environments (Figure 6a,b). The LIBS spectra of three ferrous sulfates fall into three spectral regions. Fe emission lines are predominant in the UV, blue, and VIS-NIR regions [42]. The hydrogen emission line, appearing at 656.7 nm, results from the dissociation of water molecules and hydroxyl groups. Oxygen emission lines around 778 nm are attributed to oxygen in sulfate ions S O 4 2 − , water molecules, and hydroxyl groups (OH−) within the ferric sulfates. No matter what the hydrated ferrous sulfates measured under Mars or Earth environment, the intensity and width of hydrogen emission lines are increased with the hydration degree of ferrous sulfates. However, none of the LIBS spectra for three hydrated ferrous sulfates produced sulfur lines. This absence is due to the higher detection limit for sulfur compared to other elements and the insufficient sensitivity of the LIBS system [43]. Moreover, the LIBS spectra of three hydrated sulfates differ between Earth and Mars-like environments. The signal-to-noise ratio is higher, and the peak width of iron and oxygen emission lines is narrower under Mars-like conditions. These differences are attributed to physical matrix effects.

4. Discussion and Implications for Mars

On Mars, various types of sulfate minerals have been identified by different instruments. For instance, CheMin (XRD) have identified Ca-sulfates [16], Fe(III)-sulfates [9], and Mg-sulfates [8] in different members of Gale Crater, while SHELORC (Raman) measurements have detected these sulfates in different sites within Jezero Crater [14]. In addition, sulfates also have been detected by IR instruments on orbiters and rovers, such as PanCam (UV-VNIR) on the Opportunity and Spirit rovers, OMEGA (Observatoire pour la Minéralogie, l’Eau, les Glaces et l’Activité on Mars Express orbiter) [44], and CRISM (Compact Reconnaissance Imaging Spectrometer for Mars on Mars Reconnaissance Orbiter) [45]. However, many sulfates are still inferred to exist on the Martian surface based on spectral similarities and a lack of reference data. For example, some spectra feature of three hydrated ferrous sulfates synthesized in this study as similar to ferric sulfates. Therefore, the detailed spectral features measured in this study can serve as a database for detecting three hydrated ferrous sulfates on Mars.
X-ray diffraction (XRD) is a versatile, non-destructive analytical technique employed to measure various physical properties, such as the sample’s phase and crystal structure in different materials that has been deployed in identification of minerals in geological materials on Earth and Mars. CheMin, in particular, is a miniaturized X-ray diffraction/X-ray fluorescence (XRD/XRF) instrument that was deployed on the Curiosity rover and was designed to provide detailed insights into the rocks, soils, and atmosphere of the measure targets [46]. The XRD patterns of the three hydrated ferrous sulfates would enhance the capability of CheMin in detecting these minerals within Gale Crater.
Raman spectroscopy can be used to obtain highly valuable in situ for identifying and characterizing mineral phases during planetary surface exploration, including different secondary minerals and primary minerals. Our results demonstrate that three hydrated ferrous sulfates exhibit distinct Raman features, and advance the identification of their phases indirectly from different targets. This feature holds potential value for NASA’s Mars 2020 mission, particularly with the use of the SuperCam and SHERLOC instruments [47], as well as for future Mars missions, including ExoMars’ RSL [48,49]. In addition, the Raman features of three hydrated ferrous sulfates that were measured in this study can be used to aid in distinguishing them from other minerals, such as ferric hydrated sulfates, which are less easily discerned using alternative spectroscopic techniques.
FTIR spectroscopy is the current standard for obtaining mid-infrared (MIR) spectra in laboratory settings, offering high sensitivity to both organic and inorganic phases, including both hydrous and anhydrous minerals. Based on the principles of MIR, the Thermal Emission Imaging System (THEMIS) was developed and deployed on the Mars Global Surveyor and Mars Odyssey orbiters for remote sensing from orbit [50]. Baldridge, et al. in 2013 used the THEMIS data to identify spectral features of sulfate-bearing materials in the Columbus crater on Mars [51]. The MIR spectra measured in this study would contribute to the identification of hydrated ferrous sulfates bearing minerals on Mars using thermal emission spectroscopic techniques, specifically data from THEMIS.
VNIR spectroscopy was famous as the most widely employed technique in orbital remote sensing. Nevertheless, the spectral bands in VNIR spectra of three hydrated ferrous sulfates may overlap with typical features of certain other hydrated minerals, posing challenges in distinguishing these phases accurately. Such as the bands in the range of 0.4 to 0.9 μm also appeared in ferric sulfates. Therefore, detailed VNIR features measured in this study could provide a key for VNIR payloads used to identify ferrous sulfates on Mars.
Laser-Induced Breakdown Spectroscopy (LIBS) is a versatile analytical technique that provides detailed information about the elemental composition of materials. On Mars, LIBS is a critical tool for planetary exploration, particularly in the study of the Martian surface and geology. It allows scientists to identify elemental composition, detect trace elements, analyze soil and rock chemistry, and support astrobiology by identifying elements and compounds that might indicate the presence of past or present life [52,53,54]. As part of instruments on rovers like Curiosity and Perseverance [52,53,54,55], LIBS enables real-time, in-situ analysis without the need for sample return missions, thus providing immediate data to guide further exploration. The LIBS spectra measured in this study would contribute to the identification of hydrated ferrous sulfates bearing minerals on Mars. If ChemCam on Curiosity and Super Cam on Perseverance encountered the hydrated ferrous sulfates in Gale Crater and Jezero Crater in the future detect targets, the LIBS spectra measured in this study would provide a good reference for ChemCam and Super Cam data interpretation.
On Earth, ferrous sulfates are commonly found in various geological and industrial contexts, including in soil formation, water treatment, and as a component of mining byproducts [56,57,58]. Its presence in reducing environments, such as in waterlogged soils and wetlands, can provide insights into past and present redox conditions, as well as the biogeochemical cycles of iron and sulfur [57,58]. Furthermore, ferrous sulfate plays a crucial role in the cycling of nutrients and contaminants, influencing soil fertility and water quality [59]. Studying ferrous sulfate’s behavior and transformations on Earth helps us better understand its potential role in extraterrestrial environments, such as Mars, and can guide us in developing effective strategies for managing its impacts on our own planet’s environment.
On Mars, the potential presence of ferrous sulfate provides valuable insights into the planet’s environmental history and conditions. Detection of ferrous sulfate on Mars suggests that the planet once experienced acidic and redox environments conducive to its formation, possibly involving liquid water [28,29]. This finding implies that Mars may have had significant aqueous activity in its past, which could have played a role in shaping its surface and subsurface chemistry. Understanding the distribution and formation conditions of ferrous sulfate helps us reconstruct Martian environmental conditions, such as past water activity and geochemical processes. Additionally, studying ferrous sulfate’s geochemical behavior on Mars can inform our understanding of the planet’s potential for past habitability and guide future exploration efforts in identifying regions of interest for further investigation. Generally, ferrous sulfates hold significant implications for understanding Mars and Earth’s environmental processes. But no matter what, the precise identify them using the different spectroscopies techniques is fundamental to detail understanding and revealing the geochemical and geological processes on Mars and Earth.

5. Conclusions

In this study, three hydrated ferrous sulfates were synthesized in the laboratory, and their spectroscopic properties were analyzed using XRD, Raman spectroscopy, MIR, VNIR, and LIBS techniques. The homogeneity and phase of three hydrated ferrous sulfates were confirmed by their XRD patterns. Raman spectra revealed the fundamental vibrational modes of the molecules, with the ν1 mode of S O 4 2 − being particularly prominent. To complement the Raman data and uncover additional fundamental vibrational modes, MIR spectra were collected. VNIR spectra were also obtained to expose the combination modes of water and the S O 4 2 − tetrahedron and Fe2+ electronic excitation bands. The LIBS spectra were measured under Earth and Mars conditions and the intensity of the hydrogen emission line increased with the hydrated degrees. Each sample exhibited unique spectral features that can be used to precisely determine the phase on Earth and Mars. These data will be invaluable for processing information from instruments using similar spectroscopic techniques in Mars exploration (e.g., RLS at Oxia Planum and SHERLOC at Jezero Crater). The combined features from Raman, MIR, and VNIR spectroscopy can aid in identifying Martian sulfates and understanding environmental changes on both Mars and Earth, especially in the context of assessing past water activity and climatic conditions. The spectral features and mineral profiles developed in this study are also crucial for analyzing Martian meteorites on Earth. By characterizing these meteorites spectroscopically, we gain insights into Mars’ surface composition, past water activity, and volcanic and sedimentary processes, that provide a framework for interpreting the mineralogical and chemical signatures in meteorites, enhancing our understanding of Mars’ geological history and its potential for past habitability.

Author Contributions

Conceptualization, E.S.; methodology, E.S., X.Z. and J.L.; software, R.Z.; validation, X.Z. and J.L.; formal analysis, X.Z. and J.L.; investigation, E.S., X.Z. and J.L.; resources, Z.L.; data curation, R.Z. and X.Z.; writing—original draft preparation, E.S. and X.Z.; writing—review and editing, E.S., X.Z., J.L., Z.L. and R.Z.; visualization, X.Z. and J.L.; supervision, E.S.; project administration, E.S.; funding acquisition, E.S. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by Natural Science Foundation of Shandong Province (ZR2023QD157), China Postdoctoral Science Foundation (2022M721916).

Data Availability Statement

The digital file corresponding to the spectral data in the figures of this manuscript is available by Zhuo et al. in 2024 [60], no user ID and password are required to access these data.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Changela, H.G.; Chatzitheodoridis, E.; Antunes, A.; Beaty, D.; Bouw, K.; Bridges, J.C.; Capova, K.A.; Cockell, C.S.; Conley, C.A.; Dadachova, E. Mars: New Insights and Unresolved Questions. Int. J. Astrobiol. 2021, 20, 394–426. [Google Scholar] [CrossRef]
  2. Yen, A.S.; Gellert, R.; Schröder, C.; Morris, R.V.; Bell, J.F., III; Knudson, A.T.; Clark, B.C.; Ming, D.W.; Crisp, J.A.; Arvidson, R.E. An Integrated View of the Chemistry and Mineralogy of Martian Soils. Nature 2005, 436, 49–54. [Google Scholar] [CrossRef] [PubMed]
  3. McSween, H.Y., Jr. Petrology on Mars. Am. Mineral. 2015, 100, 2380–2395. [Google Scholar] [CrossRef]
  4. Chevrier, V.; Mathé, P.-E. Mineralogy and Evolution of the Surface of Mars: A Review. Planet. Space Sci. 2007, 55, 289–314. [Google Scholar] [CrossRef]
  5. Ehlmann, B.L.; Edwards, C.S. Mineralogy of the Martian Surface. Annu. Rev. Earth Planet. Sci. 2014, 42, 291–315. [Google Scholar] [CrossRef]
  6. Vaniman, D.T.; Chipera, S.J. Transformations of Mg-and Ca-Sulfate Hydrates in Mars Regolith. Am. Mineral. 2006, 91, 1628–1642. [Google Scholar] [CrossRef]
  7. Vaniman, D.T.; Bish, D.L.; Chipera, S.J.; Fialips, C.I.; William Carey, J.; Feldman, W.C. Magnesium Sulphate Salts and the History of Water on Mars. Nature 2004, 431, 663–665. [Google Scholar] [CrossRef]
  8. Chipera, S.J.; Vaniman, D.T.; Rampe, E.B.; Bristow, T.F.; Martínez, G.; Tu, V.M.; Peretyazhko, T.S.; Yen, A.S.; Gellert, R.; Berger, J.A. Mineralogical Investigation of Mg-Sulfate at the Canaima Drill Site, Gale Crater, Mars. J. Geophys. Res. Planets 2023, 128, e2023JE008041. [Google Scholar] [CrossRef]
  9. Rampe, E.B.; Bristow, T.F.; Morris, R.V.; Morrison, S.M.; Achilles, C.N.; Ming, D.W.; Vaniman, D.T.; Blake, D.F.; Tu, V.M.; Chipera, S.J. Mineralogy of Vera Rubin Ridge from the Mars Science Laboratory CheMin Instrument. J. Geophys. Res. Planets 2020, 125, e2019JE006306. [Google Scholar] [CrossRef]
  10. Wang, A.; Ling, Z.C. Ferric Sulfates on Mars: A Combined Mission Data Analysis of Salty Soils at Gusev Crater and Laboratory Experimental Investigations. J. Geophys. Res. Planets 2011, 116. [Google Scholar] [CrossRef]
  11. Ling, Z.C.; Wang, A. A Systematic Spectroscopic Study of Eight Hydrous Ferric Sulfates Relevant to Mars. Icarus 2010, 209, 422–433. [Google Scholar] [CrossRef]
  12. Moore, R.D.; Szynkiewicz, A. Aqueous Sulfate Contributions in Terrestrial Basaltic Catchments: Implications for Understanding Sulfate Sources and Transport in Meridiani Planum, Mars. Icarus 2023, 391, 115342. [Google Scholar] [CrossRef]
  13. Yen, A.S.; Ming, D.W.; Vaniman, D.T.; Gellert, R.; Blake, D.F.; Morris, R.V.; Morrison, S.M.; Bristow, T.F.; Chipera, S.J.; Edgett, K.S.; et al. Multiple Stages of Aqueous Alteration along Fractures in Mudstone and Sandstone Strata in Gale Crater, Mars. Earth Planet. Sci. Lett. 2017, 471, 186–198. [Google Scholar] [CrossRef]
  14. Sun, V.Z.; Hand, K.P.; Stack, K.M.; Farley, K.A.; Simon, J.I.; Newman, C.; Sharma, S.; Liu, Y.; Wiens, R.C.; Williams, A.J. Overview and Results from the Mars 2020 Perseverance Rover’s First Science Campaign on the Jezero Crater Floor. J. Geophys. Res. Planets 2023, 128, e2022JE007613. [Google Scholar] [CrossRef]
  15. Langevin, Y.; Poulet, F.; Bibring, J.-P.; Gondet, B. Sulfates in the North Polar Region of Mars Detected by OMEGA/Mars Express. Science 2005, 307, 1584–1586. [Google Scholar] [CrossRef]
  16. Vaniman, D.T.; Martínez, G.M.; Rampe, E.B.; Bristow, T.F.; Blake, D.F.; Yen, A.S.; Ming, D.W.; Rapin, W.; Meslin, P.-Y.; Morookian, J.M.; et al. Gypsum, Bassanite, and Anhydrite at Gale Crater, Mars. Am. Mineral. 2018, 103, 1011–1020. [Google Scholar] [CrossRef]
  17. Nachon, M.; Clegg, S.M.; Mangold, N.; Schröder, S.; Kah, L.C.; Dromart, G.; Ollila, A.; Johnson, J.R.; Oehler, D.Z.; Bridges, J.C.; et al. Calcium Sulfate Veins Characterized by ChemCam/Curiosity at Gale Crater, Mars. J. Geophys. Res. Planets 2014, 119, 1991–2016. [Google Scholar] [CrossRef]
  18. Rapin, W.; Ehlmann, B.L.; Dromart, G.; Schieber, J.; Thomas, N.H.; Fischer, W.W.; Fox, V.K.; Stein, N.T.; Nachon, M.; Clark, B.C.; et al. An Interval of High Salinity in Ancient Gale Crater Lake on Mars. Nat. Geosci. 2019, 12, 889–895. [Google Scholar] [CrossRef]
  19. Wang, A.; Jolliff, B.L.; Liu, Y.; Connor, K. Setting Constraints on the Nature and Origin of the Two Major Hydrous Sulfates on Mars: Monohydrated and Polyhydrated Sulfates. J. Geophys. Res. Planets 2016, 121, 678–694. [Google Scholar] [CrossRef]
  20. Smith, R.J.; McLennan, S.M.; Sutter, B.; Rampe, E.B.; Dehouck, E.; Siebach, K.L.; Horgan, B.H.N.; Sun, V.; McAdam, A.; Mangold, N. X-Ray Amorphous Sulfur-Bearing Phases in Sedimentary Rocks of Gale Crater, Mars. J. Geophys. Res. Planets 2022, 127, e2021JE007128. [Google Scholar] [CrossRef]
  21. Zolotov, M.Y.; Shock, E.L. Formation of Jarosite-bearing Deposits through Aqueous Oxidation of Pyrite at Meridiani Planum, Mars. Geophys. Res. Lett. 2005, 32. [Google Scholar] [CrossRef]
  22. Lichtenberg, K.A.; Arvidson, R.E.; Morris, R.V.; Murchie, S.L.; Bishop, J.L.; Fernandez Remolar, D.; Glotch, T.D.; Noe Dobrea, E.; Mustard, J.F.; Andrews-Hanna, J. Stratigraphy of Hydrated Sulfates in the Sedimentary Deposits of Aram Chaos, Mars. J. Geophys. Res. Planets 2010, 115. [Google Scholar] [CrossRef]
  23. Gyollai, I.; Chatzitheodoridis, E.; Kereszturi, Á.; Szabó, M. Multiple Generation Magmatic and Hydrothermal Processes in a Martian Subvolcanic Environment Based on the Analysis of Yamato-000593 Nakhlite Meteorite. Meteorit. Planet. Sci. 2023, 58, 218–240. [Google Scholar] [CrossRef]
  24. Hu, S.; Lin, Y.; Zhang, J.; Hao, J.; Yamaguchi, A.; Zhang, T.; Yang, W.; Changela, H. Volatiles in the Martian Crust and Mantle: Clues from the NWA 6162 Shergottite. Earth Planet. Sci. Lett. 2020, 530, 115902. [Google Scholar] [CrossRef]
  25. Gyollai, I.; Kereszturi, A.; Chatzitheodoridis, E. Analysis of Altered Mineral Phases in Yamato 593 Martian Meteorite. In Proceedings of the 47th Annual Lunar and Planetary Science Conference, The Woodlands, TX, USA, 21–25 March 2016; p. 1911. [Google Scholar]
  26. LI, W. Some Characteristics of the Oxidation Zone of Sulfide Ore Deposits in Lower Yangtze Area, Southeast China. Min. Geol. 1983, 33, 137–147. [Google Scholar]
  27. Vigânico, E.M.; Colling, A.V.; de Almeida Silva, R.; Schneider, I.A.H. Biohydrometallurgical/UV Production of Ferrous Sulphate Heptahydrate Crystals from Pyrite Present in Coal Tailings. Miner. Eng. 2011, 24, 1146–1148. [Google Scholar] [CrossRef]
  28. Bishop, J.L.; Parente, M.; Weitz, C.M.; Noe Dobrea, E.Z.; Roach, L.H.; Murchie, S.L.; McGuire, P.C.; McKeown, N.K.; Rossi, C.M.; Brown, A.J.; et al. Mineralogy of Juventae Chasma: Sulfates in the Light-Toned Mounds, Mafic Minerals in the Bedrock, and Hydrated Silica and Hydroxylated Ferric Sulfate on the Plateau. J. Geophys. Res. E Planets 2009, 114, 1–23. [Google Scholar] [CrossRef]
  29. Pitman, K.M.; Dobrea, E.Z.N.; Jamieson, C.S.; Dalton, J.B.; Abbey, W.J.; Joseph, E.C.S. What Lurks in the Martian Rocks and Soil Investigations of Sulfates, Phosphates, and Perchlorates. Reflectance Spectroscopy and Optical Functions for Hydrated Fe-Sulfates. Am. Mineral. 2014, 99, 1593–1603. [Google Scholar] [CrossRef]
  30. Carter, J.; Poulet, F.; Bibring, J.; Mangold, N.; Murchie, S. Hydrous Minerals on Mars as Seen by the CRISM and OMEGA Imaging Spectrometers: Updated Global View. J. Geophys. Res. Planets 2013, 118, 831–858. [Google Scholar] [CrossRef]
  31. Leask, E.K.; Ehlmann, B.L.; Dundar, M.M. A 2-billion-year History of Water-alteration in Terra Sirenum, Mars: Volcanism’s Influence on Aluminum Clay Formation and Chemically Distinct Waters Forming Sulfates and Chlorides into the Amazonian. J. Geophys. Res. Planets 2024, 129, e2023JE008259. [Google Scholar] [CrossRef]
  32. Kereszturi, A. Review of Wet Environment Types on Mars with Focus on Duration and Volumetric Issues. Astrobiology 2012, 12, 586–600. [Google Scholar] [CrossRef] [PubMed]
  33. Giester, G.; Lengauer, C.L.; Redhammer, G.J. Characterization of the FeSO4. H2O-CuSO4. H2O Solid-Solution Series, and the Nature of Poitevinite, (Cu, Fe)SO4. H2O. Can. Mineral. 1994, 32, 873–884. [Google Scholar]
  34. Baur, W.H. Zur Kristallchemie Der Salzhydrate. Die Kristallstrukturen von MgSO4·4H2O (Leonhardtit) Und FeSO4·4H2O (Rozenit). Acta Crystallogr. 1962, 15, 815–826. [Google Scholar] [CrossRef]
  35. Peterson, R.C. The Relationship between Cu Content and Distortion in the Atomic Structure of Melanterite from the Richmond Mine, Iron Mountain, California. Can. Mineral. 2003, 41, 937–949. [Google Scholar] [CrossRef]
  36. Fronczek, F.R.; Collins, S.N.; Chan, J.Y. Refinement of Ferrous Sulfate Heptahydrate (Melanterite) with Low-Temperature CCD Data. Acta Crystallogr. Sect. E Struct. Rep. Online 2001, 57, i26–i27. [Google Scholar] [CrossRef]
  37. Baur, W.H. On the Crystal Chemistry of Salt Hydrates. III. The Determination of the Crystal Structure of FeSO4.7H2O (Melanterite). Acta Crystallogr. 1964, 17, 1167–1174. [Google Scholar] [CrossRef]
  38. Kazuo, N. Infrared and Raman Spectra of Inorganic and Coordination Compounds; John Wiley and Sons: New York, NY, USA, 1986; Volume 1, pp. 226–978. [Google Scholar]
  39. Cloutis, E.A.; Hawthorne, F.C.; Mertzman, S.A.; Krenn, K.; Craig, M.A.; Marcino, D.; Methot, M.; Strong, J.; Mustard, J.F.; Blaney, D.L. Detection and Discrimination of Sulfate Minerals Using Reflectance Spectroscopy. Icarus 2006, 184, 121–157. [Google Scholar] [CrossRef]
  40. Crowley, J.K.; Williams, D.E.; Hammarstrom, J.M.; Piatak, N.; Chou, I.M.; Mars, J.C. Spectral Reflectance Properties (0.4–2.5 Μm) of Secondary Fe-Oxide, Fe-Hydroxide, and Fe-Sulphate-Hydrate Minerals Associated with Sulphide-Bearing Mine Wastes. Geochem. Explor. Environ. Anal. 2003, 3, 219–228. [Google Scholar] [CrossRef]
  41. Lane, M.D.; Bishop, J.L.; Darby Dyar, M.; Hiroi, T.; Mertzman, S.A.; Bish, D.L.; King, P.L.; Deanne Rogers, A. Mid-Infrared Emission Spectroscopy and Visible/near-Infrared Reflectance Spectroscopy of Fe-Sulfate Minerals. Am. Mineral. 2015, 100, 66–82. [Google Scholar] [CrossRef]
  42. Perkins, J.J.; Sharma, S.K.; Clegg, S.M.; Misra, A.K.; Wiens, R.C.; Barefield, J.E. Remote Laser-Induced Breakdown Spectroscopy (LIBS) Analysis of Hydrated Sulfates. In Proceedings of the 40th Lunar and Planetary Science Conference, The Woodlands, TX, USA, 23–27 March 2009. [Google Scholar]
  43. Meng, F.; Shi, E.; Liu, C.; Ling, Z. Quantification of H2O in Amorphous and Crystalline Ferric Sulfates Relevant to Mars. J. Geophys. Res. Planets 2024, 129, e2023JE008091. [Google Scholar] [CrossRef]
  44. Murchie, S.L.; Seelos, F.P.; Hash, C.D.; Humm, D.C.; Malaret, E.; McGovern, J.A.; Choo, T.H.; Seelos, K.D.; Buczkowski, D.L.; Morgan, M.F. Compact Reconnaissance Imaging Spectrometer for Mars Investigation and Data Set from the Mars Reconnaissance Orbiter’s Primary Science Phase. J. Geophys. Res. Planets 2009, 114. [Google Scholar] [CrossRef]
  45. Bibring, J.-P.; Langevin, Y.; Mustard, J.F.; Poulet, F.; Arvidson, R.; Gendrin, A.; Gondet, B.; Mangold, N.; Pinet, P.; Forget, F. Global Mineralogical and Aqueous Mars History Derived from OMEGA/Mars Express Data. Science 2006, 312, 400–404. [Google Scholar] [CrossRef] [PubMed]
  46. Blake, D.; Vaniman, D.; Achilles, C.; Anderson, R.; Bish, D.; Bristow, T.; Chen, C.; Chipera, S.; Crisp, J.; Des Marais, D. Characterization and Calibration of the CheMin Mineralogical Instrument on Mars Science Laboratory. Space Sci. Rev. 2012, 170, 341–399. [Google Scholar] [CrossRef]
  47. Rull, F.; Maurice, S.; Hutchinson, I.; Moral, A.; Perez, C.; Diaz, C.; Colombo, M.; Belenguer, T.; Lopez-Reyes, G.; Sansano, A. The Raman Laser Spectrometer for the ExoMars Rover Mission to Mars. Astrobiology 2017, 17, 627–654. [Google Scholar] [CrossRef]
  48. Christensen, P.R.; Bandfield, J.L.; Bell, J.F., III; Gorelick, N.; Hamilton, V.E.; Ivanov, A.; Jakosky, B.M.; Kieffer, H.H.; Lane, M.D.; Malin, M.C. Morphology and Composition of the Surface of Mars: Mars Odyssey THEMIS Results. Science 2003, 300, 2056–2061. [Google Scholar] [CrossRef]
  49. Kereszturi, A.; Bradák, B.; Chatzitheodoridis, E.; Ujvari, G. Indicators and Methods to Understand Past Environments from ExoMars Rover Drills. Orig. Life Evol. Biosph. 2016, 46, 435–454. [Google Scholar] [CrossRef]
  50. Connell, S.A.; Wiens, R.C.; Cardarelli, E.L.; Deen, R.; Mandon, L.; Sharma, S.; Beyssac, O.; Clavé, E.; Siljeström, S.; Czaja, A.I. Analysis of Co-Located Supercam and Sherloc Observations on Abrasion Patches in Jezero Crater. In Proceedings of the 54th Lunar and Planetary Science Conference, The Woodlands, TX, USA, 13–17 March 2023; Volume 54, p. 1826. [Google Scholar]
  51. Baldridge, A.M.; Lane, M.D.; Edwards, C.S. Searching at the Right Time of Day: Evidence for Aqueous Minerals in Columbus Crater with TES and THEMIS Data. J. Geophys. Res. Planets 2013, 118, 179–189. [Google Scholar] [CrossRef]
  52. L’Haridon, J.; Mangold, N.; Meslin, P.Y.; Johnson, J.R.; Rapin, W.; Forni, O.; Cousin, A.; Payré, V.; Dehouck, E.; Nachon, M.; et al. Chemical Variability in Mineralized Veins Observed by ChemCam on the Lower Slopes of Mount Sharp in Gale Crater, Mars. Icarus 2018, 311, 69–86. [Google Scholar] [CrossRef]
  53. Rapin, W.; Meslin, P.Y.; Maurice, S.; Vaniman, D.; Nachon, M.; Mangold, N.; Schröder, S.; Gasnault, O.; Forni, O.; Wiens, R.C.; et al. Hydration State of Calcium Sulfates in Gale Crater, Mars: Identification of Bassanite Veins. Earth Planet. Sci. Lett. 2016, 452, 197–205. [Google Scholar] [CrossRef]
  54. Payré, V.; Fabre, C.; Cousin, A.; Sautter, V.; Wiens, R.C.; Forni, O.; Gasnault, O.; Mangold, N.; Meslin, P.Y.; Lasue, J.; et al. Alkali Trace Elements in Gale Crater, Mars, with ChemCam: Calibration Update and Geological Implications. J. Geophys. Res. Planets 2017, 122, 650–679. [Google Scholar] [CrossRef]
  55. Clavé, E.; Benzerara, K.; Meslin, P.; Forni, O.; Royer, C.; Mandon, L.; Beck, P.; Quantin-Nataf, C.; Beyssac, O.; Cousin, A. Carbonate Detection with SuperCam in Igneous Rocks on the Floor of Jezero Crater, Mars. J. Geophys. Res. Planets 2023, 128, e2022JE007463. [Google Scholar] [CrossRef]
  56. Matei, E.; Predescu, A.M.; Șăulean, A.A.; Râpă, M.; Sohaciu, M.G.; Coman, G.; Berbecaru, A.-C.; Predescu, C.; Vâju, D.; Vlad, G. Ferrous Industrial Wastes—Valuable Resources for Water and Wastewater Decontamination. Int. J. Environ. Res. Public. Health 2022, 19, 13951. [Google Scholar] [CrossRef] [PubMed]
  57. Johnston, S.G.; Burton, E.D.; Aaso, T.; Tuckerman, G. Sulfur, Iron and Carbon Cycling Following Hydrological Restoration of Acidic Freshwater Wetlands. Chem. Geol. 2014, 371, 9–26. [Google Scholar] [CrossRef]
  58. Karimian, N.; Johnston, S.G.; Burton, E.D. Iron and Sulfur Cycling in Acid Sulfate Soil Wetlands under Dynamic Redox Conditions: A Review. Chemosphere 2018, 197, 803–816. [Google Scholar] [CrossRef]
  59. Karimi, M. Effect of Different Levels of Irrigation Water Quality and Ferrous Sulfate Fertilizer on Yield and Yield Components of Wheat (Triticum aestivum L.). Environ. Stress. Crop Sci. 2020, 12, fa1303–fa1312. [Google Scholar]
  60. Zhuo, X.A.; Zhang, R.Z.; Shi, E.B.; Ling, Z.C.; Liu, J.H. Raman, MIR, VNIR, and LIBS spectra of three hydrated ferrous sulfates and their implication for Mars. Figshare 2024, Dataset. [Google Scholar] [CrossRef]
Universe 10 00462 g001
Figure 1. Crystal structures of (a) FeSO4⋅H2O, (b) FeSO4⋅4H2O, and (c) FeSO4⋅7H2O.
Figure 1. Crystal structures of (a) FeSO4⋅H2O, (b) FeSO4⋅4H2O, and (c) FeSO4⋅7H2O.
Universe 10 00462 g001
Universe 10 00462 g002
Figure 2. The XRD pattern of three hydrated ferrous sulfates.
Figure 2. The XRD pattern of three hydrated ferrous sulfates.
Universe 10 00462 g002
Universe 10 00462 g003
Figure 3. The Raman spectra of three hydrated ferrous sulfates.
Figure 3. The Raman spectra of three hydrated ferrous sulfates.
Universe 10 00462 g003
Universe 10 00462 g004
Figure 4. The MIR spectra of three hydrated ferrous sulfates.
Figure 4. The MIR spectra of three hydrated ferrous sulfates.
Universe 10 00462 g004
Universe 10 00462 g005
Figure 5. The VNIR spectra of three hydrated ferrous sulfates.
Figure 5. The VNIR spectra of three hydrated ferrous sulfates.
Universe 10 00462 g005
Universe 10 00462 g006
Figure 6. The laser-induced breakdown spectroscopy (LIBS) spectra of three hydrated ferrous sulfates were obtained from (a) the Earth environment and (b) Mars-like conditions.
Figure 6. The laser-induced breakdown spectroscopy (LIBS) spectra of three hydrated ferrous sulfates were obtained from (a) the Earth environment and (b) Mars-like conditions.
Universe 10 00462 g006
Table 1. Raman peak position (cm−1) of three hydrated ferrous sulfates.
Table 1. Raman peak position (cm−1) of three hydrated ferrous sulfates.
SampleH2O ModeSO4 ModeOthers
StretchingBendingν1ν2ν3ν4Lattice-Vibration
FeSO4·H2O3242.81478.31017.2421.91073.1615.4111.5
3334.51625.9 492.71091.4622.3
3422.01750.0 1193.9661.2
FeSO4·4H2O3325.61591.2989.7457.01071.1580.3105.6
3378.21629.0 480.31096.1606.7148.1
3448.51679.8 1146.0625.7166.2
3530.9 1176.6660.5
3595.9
FeSO4·7H2O3228.91593.8976.8452.81069.5608.9141.1
3354.81649.5 460.51099.4620.7183.4
3438.8 1143.6 209.9
3522.2 239.1
377.2
Table 2. MIR peak position (cm−1) and assignment of three hydrated ferrous sulfates.
Table 2. MIR peak position (cm−1) and assignment of three hydrated ferrous sulfates.
SampleH2O ModeSO4 Mode
StretchingBendingν1ν2ν3ν4
FeSO4·H2O3233.81501.11015.6524.41084.1603.5
3372.61644.9 544.11134.3625.1
1176.8668.0
FeSO4·4H2O3233.81596.1987.2425.11092.6611.3
3372.61621.5 437.81156.0
3467.71653.9
3550.71660.5
FeSO4·7H2O3228.61596.5976.0418.41086.4607.8
3385.11621.0988.1424.31158.7617.7
3464.11651.1 431.9
3563.01673.8 442.3
Table 3. VNIR features position (cm−1) and assignment of three hydrated ferrous sulfates.
Table 3. VNIR features position (cm−1) and assignment of three hydrated ferrous sulfates.
FeSO4·H2OFeSO4·4H2OFeSO4·7H2OAssignment
0.430.435T2g→3T2g
0.450.455T2g→3T2g
0.470.475T2g→3T2g
0.510.515T2g→1A1g
0.940.980.925Eg→5B1g
1.171.17E1g→T2g
1.33 5Eg→5A1g
1.521.451.462 ν 1 W or 2 ν 3 W
1.951.95 ν 1 W + ν 2 W (or ν 3 W )
1.991.98 ν 1 W + ν 2 W (or ν 3 W )
2.242.25 ν 1 W (or ν 3 W ) + ν 3 S O 4
2.402.442.41 ν 2 W + ν 1 S O 4 + ν 3 S O 4
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Zhuo, X.; Zhang, R.; Shi, E.; Liu, J.; Ling, Z. Raman, MIR, VNIR, and LIBS Spectra of Szomolnokite, Rozenite, and Melanterite: Martian Implications. Universe 2024, 10, 462. https://doi.org/10.3390/universe10120462

AMA Style

Zhuo X, Zhang R, Shi E, Liu J, Ling Z. Raman, MIR, VNIR, and LIBS Spectra of Szomolnokite, Rozenite, and Melanterite: Martian Implications. Universe. 2024; 10(12):462. https://doi.org/10.3390/universe10120462

Chicago/Turabian Style

Zhuo, Xiai, Ruize Zhang, Erbin Shi, Jiahui Liu, and Zongcheng Ling. 2024. "Raman, MIR, VNIR, and LIBS Spectra of Szomolnokite, Rozenite, and Melanterite: Martian Implications" Universe 10, no. 12: 462. https://doi.org/10.3390/universe10120462

APA Style

Zhuo, X., Zhang, R., Shi, E., Liu, J., & Ling, Z. (2024). Raman, MIR, VNIR, and LIBS Spectra of Szomolnokite, Rozenite, and Melanterite: Martian Implications. Universe, 10(12), 462. https://doi.org/10.3390/universe10120462

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop