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Partic. vol. 33 pp. 29-34 (August 2017)
doi: 10.1016/j.partic.2016.10.003

Effect of precursor thermal history on the formation of amorphous and crystalline calcium carbonate

Jitendra Pal Singha,*, Mi-Jung Jia, Cheol-Hwee Shima, Sang Ok Kimb, Keun Hwa Chaea,*

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jitendra_singh2029@rediffmail.comkhchae@kist.re.kr

Highlights

    • Amorphous and crystalline phases of calcium carbonate were synthesized from calcium nitrate. • The amorphous or crystalline phases were unaffected by the thermal history of the precursor. • Electronic structure was sensitive to precursor thermal history and annealing.

Abstract

The role of the thermal history of the precursor was studied for amorphous and crystalline calcium carbonate phases synthesized from calcium nitrate. The X-ray diffraction patterns of these phases are influenced by their annealing temperature of 0, 300, 400, and 500 °C. However, the effect of the precursor thermal history on the X-ray diffraction pattern of the resulting calcium carbonate phase is negligible. Transmission electron microscopy indicates that materials annealed at 400 °C consist of amorphous aggregates, irrespective of the precursor thermal history. The crystallite size of crystalline calcium carbonate is influenced by the precursor thermal history, and ranges from 23 to 26 nm. Near-edge X-ray absorption fine structure measurements indicate that the annealing temperature plays an important role in determining the local electronic structure. The role of the thermal history of the precursor is also important for the resulting electronic structure.

Graphical abstract

Keywords

Amorphous material; Particles; Electron microscopy; X-ray techniques; NEXAFS; Calcium carbonate