Click here to view fulltext PDF

Permanent link:
https://www.ias.ac.in/article/fulltext/jcsc/127/05/0843-0848

Calcium carbonate; chemical synthesis; vaterite; polymorphism; X-ray diffraction; morphology.

Calcium carbonate polymorphs were precipitated at room temperature and 80$^{\circ}$C by varying the precipitation pH, carbonate source, effect of solvent in presence and absence of structure directing agent such as para-aminobenzoic acid. Calcite phase of calcium carbonate was obtained when sodium hydrogen carbonate and/or sodium carbonate (used as precipitating agents) were added to calcium chloride solution at different pHs in water and/or methanol as solvent in separate experiments. Vaterite phase of calcium carbonate (CaCO₃) has been synthesized by mixing calcium chloride and sodium carbonate in presence of para-aminobenzoic acid when water–methanol binary mixture was used as solvent. Vaterite phase of calcium carbonate crystallizes in P63/mmc, while that of calcite phase in R-3mc, respectively. Calcite phase of calcium carbonate exhibits rhombohedral morphology, while vaterite phase has spherical morphology.

T N Ramesh¹ S A Inchara¹ K Pallavi¹

1. Department of Studies and Research in Chemistry and Prof. C N R Rao Centre for Advanced Materials, Tumkur University, Tumkur 572 103, India

Published

May 2015

Manuscript received

24 July 2014

Manuscript revised

25 November 2014

Accepted

30 November 2014