The Aragonite Raman spectrum and its interpretation are presented below.
Aragonite sample data
| Description: | Aragonite mineral sample |
|---|---|
| Mineral: | Aragonite |
| RAMAN ID: | RAMAN5413 |
| Ideal chemistry: | CaCO3 |
| Source: | Grigore Cobălcescu Museum |
| Locality: | Mexic |
| Owner: | Department of Geology – Alexandru Ioan Cuza University of Iasi |
Aragonite sample image
Raman spectrum of Aragonite
Main Raman bands of Aragonite
| Wavenumbers (cm-1): | 1083vs, 701w, 250m |
|---|
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 Aragonite
The characteristic Raman band due to the external vibration mode (M-CO3) at 250 cm-1, and the ν1 internal mode (symmetric stretching) at 1083 cm-1 are easily distinguished. In the Raman spectrum of the aragonite sample don’t have values below 200 cm-1 because the spectral range is between 200-3400 cm-1.
In case of aragonite only four bands out of the 30 predicted Raman-active modes (Urmos et al., 1991) were detected in the Raman spectra of the aragonite sample no. 5473. This spectrum is governed by the very strong Raman line (1083 cm-1) atributed to the ν1 symmetric stretching mode of the carbonate group. The ν4 mode of CO3 has values at 701 cm-1. The ν2 vibration mode is not observed in this study; ν3 vibration are observed at 1461 and 1573 cm-1.
The frequencies of all Raman bands observed in Aragonite, Strontianite and Witherite can be corelated with the atomic masses of the cations (Buzgar and Apopei, 2009).
| Buzgar and Apopei, 2009 | Urmos, 1991 | Krishnamurti, 1960 | Assignment |
| 250 | 284 | 285 | T(Ca,CO3) |
| 701 | 701 705 |
702 707 716 |
ν4 symmetric deformation |
| NO | 853 | 854 | ν2 asymmetric deformation |
| 1083 | 1085 | 1086 | ν1 symmetric stretch |
| 1461 1573 |
1462 1547 |
1415 1463 |
ν3 asymmetric stretching |
| 1547 | NA | ||
| NO | 2165 | 2ν1 |
NO = not observed; NA = not assigned.
References for the Raman spectrum of Aragonite
- BUZGAR 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]
- URMOS J., SHARMA S. K., MACKENZIE F. T. (1991) – Characterization of some biogenic carbonates with Raman spectroscopy. American Mineralogist, 76, p. 641-646 [link]
- KRISHNAMURTI D. (1960) – The Raman spectra of aragonite, strontianite and witherite. Indian Academy of Sciences [link]