X-ray diffraction studies of crystal structures and phase transitions in K1−x(NH4)xCl mixed salts

Crystal structures and phase transitions of K
_1-x
(NH
₄
)
_x
Cl mixed salts with non-stoichiometric composition x=0.1, 0.2, 0.5, 0.6 and 0.8 have been studied by x-ray diffraction technique. It was established that at the room temperature K
_0.8
(NH
₄
)
_0.2
Cl and K
_0.9
(NH
₄
)
_0.1
Cl compounds have Fm3̅m symmetry and K
_0.2
(NH
₄
)
_0.8
Cl compound has Pm3m, when K
_0.5
(NH
₄
)
_0.5
Cl and K
_0.4
(NH
₄
)
_0.6
Cl compounds consist of two phases with space groups Fm3̅m + Pm3m. Lattice parameters, positions and thermal factors of K, N and CI atoms have been refined using x-ray diffraction study for each mixed crystals.