Siderite Raman spectrum

The Siderite Raman spectrum and its interpretation are presented below.


Siderite sample data

Description: Siderite mineral sample
Mineral: Siderite
RAMAN ID: RAMAN5455
Ideal chemistry: FeCO3
Source: Grigore Cobălcescu Museum
Locality: Lobenstein – Germany
Owner: Department of Geology – Alexandru Ioan Cuza University of Iasi

Siderite sample image

Siderite Raman spectrum

Raman spectrum of Siderite


Main Raman bands of Siderite

Wavenumbers (cm-1): 1087vs, 737w, 289m

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 Siderite

The Raman spectrum of siderite is characterized by the same band of calcite at 1087 cm-1 corresponding to the symmetric stretching of CO3 group. The band at 737 cm-1 corresponds to the ν4 (O-C-O in-plane bending) vibrational mode and 1442 cm-1 to ν3 mode.

The observed vibrational bands of siderite 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)
190 T(Fe, CO3)
289 294 T(Fe, CO3)
514 506 Fe-O
737 731
742
680 ν4 symmetric CO3 deformation
879 ν2 asymmetric CO3 deformation
1087 1087 1063 ν1 symmetric CO3 stretching
1442 1415 ν3 asymmetric CO3 stretching
1729 1726
1733
ν1 + ν4

The lower wavenumbers of siderite (289 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 spectrum also presents a band at 514 cm-1, wich may be assigned to the vibration of a Fe-O bond.

The positions of the observed Raman bands are in agreement with those reported by Beny, 1991.

References for the Raman spectrum of Siderite

  • 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]
  • BENY C. (1991) – Societe Francaise de Mineralogie et de Cristallographie – Base donnees de spectres Raman. Siderite [link]

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