The thermochemistry of crystalline $\rm M_3\rm AlF_6$, $\rm NaAlF_4$, $\rm KAlF_4$ and gaseous $\rm MAlF_4$ fluoroaluminates of alkali metals, $\rm M$

The formation enthalpies of crystalline $\rm M_3\rm AlF_6$ and gaseous $\rm NaAlF_4$ are confirmed and refined and the formation enthalpy of $\rm KAlF_4$(cryst.) is estimated for $\rm MF$–$\rm\rm AlF_3$ systems $(\rm M$ is $\rm Li, \rm Na$, or $\rm K)$ with a minimum in the total saturated vapor pressure.