Thermodynamic and structural investigations of chlorides in the systems KCl/MgCl2 and KCl/MnCl2

Thermodynamic evaluation and optimization of the (NaCl+KCl+MgCl2+CaCl2+MnCl2+FeCl2+CoCl2+NiCl2) system

“…No solid solubility was reported and the measured limiting slopes of the KCl and MnCl 2 liquidus curves agree with equation (10) [16,17,19], K 2 MnCl 4 [18], K 3 Mn 2 Cl 7 [18,19], K 4 Mn 3 Cl 10 [42] and KMnCl 3 [16][17][18][19]41]. The existence of K 4 MnCl 6 and KMnCl 3 was confirmed by X-ray diffraction [17].…”

“…A transition to a second form of KMnCl 3 occurs at a temperature which can vary between 150°C and 270°C [43], probably due to kinetic effects. This new form is tetragonal with the GdFeO 3 structure [42]. A transition to a cubic form of KMnCl 3 occurs at 386 (AE2)°C [42].…”

“…This new form is tetragonal with the GdFeO 3 structure [42]. A transition to a cubic form of KMnCl 3 occurs at 386 (AE2)°C [42]. Only the high temperature (cubic) form of KMnCl 3 is considered in the present calculations owing to the unavailability of relevant thermodynamic data for the other forms.…”

“…Only the high temperature (cubic) form of KMnCl 3 is considered in the present calculations owing to the unavailability of relevant thermodynamic data for the other forms. The enthalpy of formation of KMnCl 3 from solid KCl and MnCl 2 at T ¼ 298:15 K has been measured by solution calorimetry [42]. The value obtained (as well as the value calculated from the present optimization) is )15.53 kJ Á mol À1 .…”

Retarded solid state reactions III [1]

“…A quotation from their paper: "X-ray examination of these materials after storage in evacuated and sealed glass ampoules for 3-4 years revealed partial transformation of these materials to the new phase." A much better way to prepare the room temperature phase is the dehydration of the hydrate KMnCla.2H20 at 90~ This compound reveals a thermic effect in a heating curve at 267~ with a transition enthalpy of 4.60 kJ tool -1, measured by DSC [6].…”