Thermodynamic properties and structural geometry of KMgCl 3 ·6H 2 O single crystals

Abstract

The thermodynamic properties and structural geometry of KMgCl 3 ·6H 2 O were investigated using thermogravimetric analysis, differential scanning calorimetry, and nuclear magnetic resonance. The initial mass loss occurs around 351 K (=T d ), which is interpreted as the onset of partial thermal decomposition. Phase transition temperatures were found at 435 K (=T C1 ) and 481 K (=T C2 ). The temperature dependences of the spin–lattice relaxation time T 1 for the 1 H nucleus changes abruptly near T C1 . These changes are associated with changes in the geometry of the arrangement of octahedral water molecules.