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Epsomite: Crystal structure | Sample photo | Raman spectrum | Interpretation | References

Crystal structure of Epsomite

Formula:

MgSO4•7(H2O)

Crystal Data:

Crystal System: Orthorhombic - Disphenoidal

Point Group: 2 2 2

Cell Data:

Space Group: P 212121, a = 11.86, b = 11.99, c = 6.858, Z = 4

Using the mouse (click here for more information)

Density (calc.) = 1.68 and V = 975.22 Å3
Element color: Mg, S, O, H
Epsomite sample
Epsomite

Synthetic sample




Click image to enlarge
Raman spectrum and vibrations of Epsomite
Element color: S, O Toggle Grid Toggle Coordinates Reverse Spectrum

Click to in the Raman spectrum. To see the vibrations click on one of them (highlight region) and it (the selected vibration) will appear on the right side of the Raman spectrum.
Below spectra are various settings, and other vibrations of epsomite (which are not present in this spectrum).
You have the possibility to zoom in the spectrum by selecting a spectral region you need to be increased (along axis x); to zoom keep the left mouse-click continously pressed, drag (to left or to right) and release the left button. To return to the initial size spectrum, press the right click on the spectrum -> Zoom -> Reset View.
Model type:
Sticks Ball-and-Sticks (1) Ball-and-Sticks (2) CPK (Spacefill)

Orientation:
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SO4 polyhedra on SO4 polyhedra off 		Vibrations:
ν2 SO4 ν4 SO4 ν1 SO4 ν3 SO4

Vibration on Vibration off 		Download spectrum:
Raman spectrum .txt Raman spectrum .spc


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Interpretation of Raman spectrum of Epsomite

The Raman spectrum of epsomite shows an intense ν1 vibration of SO4 group at 985 cm-1. The ν2 mode appear at 469 cm-1. Two bands, one at 1084 cm-1 and one at 1146 cm-1 have been assigned to the ν3 mode and the band at 611 cm-1 to the ν4. The bands 246 cm-1 and 365 cm-1 were assigned to the vibrations of the Fe-O bond (where O is from H2O). The vibration modes of water appear at 3397 cm-1. In early studies, Lakshman (1941) reported for epsomite the vibrational modes of sulfate group and water molecule, and later, Shantakumari (1953) reported more bands, especially for water vibrations.


Epsomite Assignments
Buzgar et al., 20091 Lakshman, 1941 Shantakumari, 1953
246 252 T(M, H2O)
365 303
445 ν2 SO4
469 455 461
611 613 609 ν4 SO4
620
985 981 986 ν1 SO4
1046 1059 ν3 SO4
1064
1084 1076
1101 1098
1134
1146 1148
3185 ν(H2O)
3226 3228
3285 3338
3397 3406
3458 3446
References

• The Mineralogy Database [link]

• Crystal data (.cif file) from the American Mineralogist Crystal Structure Database [link]

• 1BUZGAR N., BUZATU A., SANISLAV I. V. (2009) - The Raman study on certain sulfates. Analele Stiintifice ale Universitatii “Al. I. Cuza” - Iasi, Tome 55, issue 1, 5-23 [link]

• Lakshman, R. B. (1941) - Raman spectra of some crystalline nitrates and sulphates. Proceedings of the Indian Academy of Science A,14, 49-54. [link]

• Shantakumari, C. (1953) - Raman spectra of crystalline sulphates of zinc, magnesium and sodium. Proceedings of the Indian Academy of Science A, 37, 393-399. [link]