Abstract
Monohydrocalcite (MHC) is hydrous calcium carbonate of which composition is CaCO3. H2O. Based on the crystal structure of MHC, Mg is incompatible to structure of MHC. However, it is well recognized that the significant amount of Mg is associated with MHC. This study examines the chemical states of Mg associated with MHC by means of synchrotron based XANES analyses of synthesized MHC with different Mg contents.