The Rhodochrosite Raman spectrum and its interpretation are presented below.
Rhodochrosite sample data
| Description: | Rhodochrosite mineral sample |
|---|---|
| Mineral: | Rhodochrosite |
| RAMAN ID: | RAMAN5438 |
| Ideal chemistry: | MnCO3 |
| Source: | Grigore Cobălcescu Museum |
| Locality: | Kohlenbach – Germany |
| Owner: | Department of Geology – Alexandru Ioan Cuza University of Iasi |
Rhodochrosite sample image
Raman spectrum of Rhodochrosite
Main Raman bands of Rhodochrosite
| Wavenumbers (cm-1): | 1094vs, 726w, 293m |
|---|
Raman parameters
| Instrument settings: | Raman spectrograph HE 532nm (Horiba Jobin-Yvon) |
|---|---|
| Spectral resolution: | 2 cm-1 |
| Conditions of measurement: | at room temperature |
Interpretation of Raman spectrum of Rhodochrosite
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 and Apopei, 2009 | Beny, 1991 | Free CO32- | Assignment |
| R*(CO3) | |||
| 184 | T(Mn, CO3) | ||
| 293 | 289 | T(Mn, 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 |
R* – rotational
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, 1991.