SPAFMSR



Buzgar N., Apopei A. I., Buzatu A. (2009) - Romanian Database of Raman Spectroscopy (http://rdrs.uaic.ro)
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Formula: |
MnCO3 |
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Crystal Data: |
Crystal System: Trigonal - Hexagonal Scalenohedral |
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Point Group: 3 2/m |
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Cell Data: |
Space Group: R 3c, a = 4.777, c = 15.67, Z = 6 |
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Density (calc.) = 3.70 and V = 309.68 Å3 |
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Element color: Mn, C, O |
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Sample no. 5438 from the "Mineralogy and Petrography Museum Grigore Cobălcescu" of "Alexandru Ioan Cuza" University, Iaşi. Origin: Kohlenbach - Germany. Click image to enlarge |
The Raman spectrum of rhodochrosite consists in a strongest intensity band at 1094 cm-1 assigned to symmetric stretching mode ν1 of CO3 group, the ν3 mode appears at 1439 cm-1 and the ν4 mode at 726 cm-1.
The observed vibrational bands of rhodochrosite compared with well-documented values are listed below. The minor shift in positions may be due to the effects of natural impurities present in the sample.
Buzgar et al., 20091 | Beny, 1991 | Free CO32- | Assignment |
R*(CO3) | |||
184 | T(Ca, CO3) | ||
293 | 289 | T(Ca, CO3) | |
726 | 718 | 680 | ν4 symmetric CO3 deformation |
879 | ν2 asymmetric CO3 deformation | ||
1094 | 1064 1085 |
1063 | ν1 symmetric CO3 stretching |
1439 | 1414 | 1415 | ν3 asymmetric CO3 stretching |
1752 | 1725 | ν1 + ν4 |
The lower wavenumbers of rhodochrosite (293 cm-1) observed in the above table, arise from the external vibration of the CO3 group that involve translatory oscillations of the group (relative translations between the cation and anionic group). In this spectrum are no values below 200 cm-1 because the spectral range is between 200 - 3400 cm-1.
A weak line observed at 1729 cm-1 may be regarded as the combination band of ν1 + ν4.
The positions of the observed Raman bands are in agreement with those reported by Beny C., 1991.
• The Mineralogy Database [link]
• Crystal data (.cif file) from the American Mineralogist Crystal Structure Database [link]
• 1BUZGAR N., APOPEI A. I. (2009) - The Raman study on certain carbonates. Analele Stiintifice ale Universitatii “Al. I. Cuza” - Iasi, Tome 55, issue 2, 97-112 [link]
• BENY C. (1991) - Societe Francaise de Mineralogie et de Cristallographie - Base donnees de spectres Raman. Rhodochrosite [link]