Synthesis, characterization and thermal analysis of K2M(SO4)2·6H2O (M = Mg, Co, Cu)

Synthesis, characterization and thermal behavior for Tutton’s salts K 2 M(SO 4 ) 2 ·6H 2 O (M = Mg, Co, Cu) are reported. These double salts crystallize in the monoclinic system, with the space group P 2 1 a ( Z = 2). The unit-cell parameters were affined with “Affma” software. The IR spectrums reveal also the vibrational characteristic of water and sulfates. Thermogravimetry, differential thermal analysis and XRD at high-temperature investigations show that the dehydration of these salts occurs between 70 and 200 °C. This indicates the removal of all water molecules around 200 °C. Schemes of their decomposition are proposed. While K 2 M(SO 4 ) 2 ·6H 2 O (M = Mg, Co, Cu) salts are isostructural, they do not exhibit the same decomposition steps.