Phase Equilibrium of the System TbCl 3 -CdCl 2 -HCl(7.92 wt %)-H 2 O at 298.15 ± 0.1 K 1

The equilibrium solubility of the quaternary system TbCl 3 -CdCl 2 -HCl(7.92 mas. %)-H 2 O was determined at 298K and the corresponding equilibrium diagram was constructed. The quaternary system is complicated by the three equilibrium solid phases: CdCl 2 · H 2 O, TbCd 4 Cl 11 · 14H 2 O (4: 1 type), and TbCl 3 · 6H 2 O, of which the new compound Cd 4 TbCl 11 · 14H 2 O was found to be congruently soluble in the system. The new compound obtained was identified and characterized by the method of X-ray diffraction and the thermal analysis methods of thermogravimetry-differential thermogravimetry (TG-DTG).