SPAFMSR



Buzgar N., Apopei A. I., Buzatu A. (2009) - Romanian Database of Raman Spectroscopy (http://rdrs.uaic.ro)
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Formula: |
K2CO3 |
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Crystal Data: |
Crystal System: Hexagonal - Dihexagonal Pyramidal |
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Point Group: 6mm |
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Cell Data: |
Space Group: P 63mc, a = 5.215, c = 6.584, Z = 2 |
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Density (calc.) = 2.27 and V = 155.07 Å3 |
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-1 (ν4a) and 702 cm-1 (ν4b). 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 et al., 20091 | Koura, 1966 | Koura, 1966 | Assignment |
Calculated | Measured | ||
237 288 484 |
76, 85 122, 252, 278, 291 |
126, 141, 192 |
T(K,CO3) |
677 | 688 | 692 | ν4a (E') symmetric deformation |
702 | 706 | 697 | ν4b (E') symmetric deformation |
1026 1063 |
1025 | 1043 1064 |
ν1 (A'1) symmetric stretch |
1374 | 1385 | 1405 | ν3a (E') asymmetric stretch |
1426 | 1557 | ν3b (E') asymmetric stretch |
• The Mineralogy 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]
• 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]