Potassium carbonate (synthetic) (K2CO3) Raman spectrum

The Potassium carbonate (synthetic) (K2CO3) Raman spectrum and its interpretation are presented below.

Potassium carbonate sample data

Description: Potassium carbonate mineral sample
Mineral: Potassium carbonate (synthetic) (K2CO3)
Ideal chemistry: K2CO3
Source: Grigore Cobălcescu Museum
Owner: Department of Geology – Alexandru Ioan Cuza University of Iasi

Potassium carbonate sample image

Raman spectrum of Potassium carbonate (synthetic) (K2CO3)

Main Raman bands of Potassium carbonate (synthetic) (K2CO3)

Wavenumbers (cm-1): 1063vs

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 Potassium carbonate (synthetic) (K2CO3)

The Raman spectrum of K2CO3 shows a couple of bands at 1026 and 1063 cm-1 that may be attributed to the ν1 symmetric stretching mode. The two bands may be explained by the presence of the molecules belonging to two structures, C2v bidentate form and D3h, in agreement with the theoretical values calculated by Koura et al. (1996). The ν2 vibration mode is not Raman active. The bands at 1374 cm-1 and 1426 cm-1, can be assigned to ν3a respectively ν3b. To the ν4 mode (doubly degenerate symmetric bending) are attributed the values of 677 cm-14a) and 702 cm-14b). The spectrum also presents three bands at 237 cm-1, 287 cm-1 and 484 cm-1, which may be assigned to the external vibration modes between the cation and anionic group (T(K,CO3)).

The frequency of the detected bands is reported in below table.

Buzgar and Apopei, 2009 Koura, 1966 Koura, 1966 Assignment
Calculated Measured
76, 85 122,
252, 278, 291
126, 141,
677 688 692 ν4a (E’) symmetric deformation
702 706 697 ν4b (E’) symmetric deformation
1025 1043
ν1 (A’1) symmetric stretch
1374 1385 1405 ν3a (E’) asymmetric stretch
1426 1557 ν3b (E’) asymmetric stretch

NO = not observed; NA = not assigned

References for the Raman spectrum of Potassium carbonate

  • 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]
  • KOURA N., KOHARA S., TAKEUCHI K., TAKAHASI S., CURTISS L. A., GRIMSDITCH M., SABOUNGI M. L. (1996) – Alkali carbonates: Raman spectroscopy, ab initio calculations and structure. Journal of Molecular Structure, 382, p. 163-169 [link]

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