Metal halides are promising ammonia (NH3) absorption/desorption materials for hydrogen energy transport. In this study, a new NH3 carrier material, Ca-0.5,Sr-0.5 (NH3)(8)Cl-2, was synthesized, and its crystal structure and NH3 desorption properties were analyzed. The crystal structure of the new material was orthorhombic (space group: Pnma) at 296 +/- 2K, and was similar to those of Ca(NH3)(8)Cl-2 and Sr(NH3)(8)Cl-2. Its crystal volume was intermediate between those of Ca(NH3)(8)Cl-2 and Sr(NH3)(8)Cl-2, and its NH3 desorption equilibrium pressure (490kPa) was also intermediate between those of Ca(NH3)Cl-2 (583 kPa) and Sr(NH3)(8)Cl-2 (420 kPa) at 342 K. Thus, the NH3 desorption properties of Ca1-xSrx(NH3)(8)Cl-2 may be controlled by varying the value of x.