The phase relationships of the quaternary systems LiCl-MnCl2-GaCl3 and LiCl-MnCl2-InCl3 as well as LiCl-CdCl2-(MCl3)-Cl-III (M-III = Ga, In, Fe, Al) have been studied by X-ray and Raman spectroscopic experiments. The crystal structures of spinel-type Li1.9Mn0.9Ga0.1Cl4 and Li1.65Mn0.65In0.35Cl4 have been determined by X-ray powder and X-ray single-crystal studies, respectively. The gallium and indium ions occupy octahedral sites of the spinel structure as shown by both the spectroscopic and the structure studies. As novel quaternary compounds isotypic (LiMInCl6)-In-II (M-II = Mg, Mn, Fe, Co, Cd) have been established. The electric conductivity of spinel-type solid solutions (Li2-xMn1-xMxCl4)-Cl-III (M-III = Ga, In), which are fast ionic conducting materials, decreases with increasing In3+ content, but partly increases with higher Ga3+ content. The two-phase material Li1.7Mn0.7Ga0.3Cl4 displays an ionic conductivity of 6.4 x 10(-2) Omega(-1) cm(-1) even at 200 degrees C.