AbstractDecylammonium tetrachlorozincate (n‐C10H21NH3)2ZnCl4(C10ZnCl), dodecylammonium tetrachlorozincate (n‐C12H25NH3)2ZnCl4(C12ZnCl) and hexadecylammonium tetrachlorozincate (n‐C16H33NH3)2ZnCl4‐(C16ZnCl) were synthesized and a series of their mixtures C10ZnCl‐C16ZnCl and C12ZnCl‐C16ZnCl were prepared. The experimental binary phase diagrams of C10ZnCl‐C16ZnCl and C12ZnCl‐C16ZnCl were established by means of differential scanning calorimetry (DSC), IR and X‐ray diffraction. In the phase diagram a stable solid compound and two eutectoid invariants were observed. It is noticeable that the phase diagram contains soli