Witherite Raman spectrum

The Witherite Raman spectrum and its interpretation are presented below.


Witherite sample data

Description: Witherite mineral sample
Mineral: Witherite
RAMAN ID: RAMAN5484
Ideal chemistry: BaCO3
Source: Grigore Cobălcescu Museum
Locality: Alston – England
Owner: Department of Geology – Alexandru Ioan Cuza University of Iasi

Witherite sample image

Witherite Raman spectrum

Raman spectrum of Witherite


Main Raman bands of Witherite

Wavenumbers (cm-1): 1059vs, 693w, 227m

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 Witherite

The characteristic Raman band due to the external vibration mode (M-CO3) at 227 cm-1 and 222 cm-1, 285 cm-1 for witherite and synthetic BaCO3, respectively, and the ν1 internal mode (symmetric stretching) for both witherite sample at 1059 cm-1 are easily distinguished. In the Raman spectrum of the witherite and synthetic BaCO3 samples don’t have values below 200 cm-1 because the spectral range is between 200-3400 cm-1.

The Raman spectra for the witherite and synthetic BaCO3 are very similar the only differences are found in the 200-300 cm-1 region. In the synthetic BaCO3 spectra appear one peak in addition at 285 cm-1 attributed to the external vibration mode. As can be seen in Raman spectra, witherite and BaCO3 synthetic do not present values below 200 cm-1 because the spectral range is between 200-3400 cm-1. The intense ν1 symmetric stretching mode of carbonate group is at 1059 cm-1 for both spectra. The bands at 1422 cm-1 and 1421 cm-1 are due to the ν3 asymmetric stretching mode, and the bands at 1511 cm-1 and 1508 cm-1 are not assigned. The ν2 vibration mode is not observed. The Raman line at 693 cm-1 is attributed to ν4 vibration.

 

Buzgar and Apopei, 2009 Buzgar and Apopei, 2009 Krishnamurti, 1960 Beny, 1989 Assignment
sample no. 5484 synthetic BaCO3
227 222, 285 227 224 T(M,CO3)
693 693 691
699
690
696
v4 – symmetric deformation
NO NO 852* v2 – asymmetric deformation
1059 1059 1061 1035
1059
v1 – symmetric stretch
1422
1511
1421
1508
1394
1409
1421
1419
1505
v3 – asymmetric stretching
NO NO 2116* 2v1

The frequencies marked with asterisk are reported for the first time.
NO = not observed.

References for the Raman spectrum of Witherite

  • 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]
  • KRISHNAMURTI D. (1960) – The Raman spectra of aragonite, strontianite and witherite. Indian Academy of Sciences [link]
  • BENY C. (1989) – Societe Francaise de Mineralogie et de Cristallographie – Base donnees de spectres Raman. Witherite [link]

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