Dataset for "Magnesium Ions Direct the Solid-State Transformation of Amorphous Calcium Carbonate Thin Films to Aragonite, Magnesium-Calcite or Dolomite"

This dataset supports work showing that remarkable control can be achieved over the chemical composition and structure of crystalline calcium carbonate by using heat to drive a pseudomorphic transformation of ACC thin films. The crystal polymorph can be tuned from low magnesium-calcite to pure aragonite, high magnesium-calcite and ultimately dolomite according to the magnesium content of the ACC, and mosaics of large single crystals are generated at elevated temperatures rather than the spherulitic structures formed at room temperature. This methodology also enabled an in situ investigation of the ACC crystallization mechanism using Transmission Electron Microscopy. Finally, our approach can be combined with templating methods to generate arrays of large aragonite single crystals with pre-selected morphologies. These results demonstrate that exceptional control can be achieved through the solid-state transformation of Mg-ACC, which has relevance to both synthetic and biological systems.