GaAlAs2 is Lavarevi\'{c}ite-like structured and crystallizes in the trigonal R3m space group. Ga(1) is bonded to one As(2) and three equivalent As(1) atoms to form GaAs4 tetrahedra that share corners with six equivalent Ga(1)As4 tetrahedra and corners with six equivalent Al(1)As4 tetrahedra. Al(1) is bonded to one As(1) and three equivalent As(2) atoms to form AlAs4 tetrahedra that share corners with six equivalent Ga(1)As4 tetrahedra and corners with six equivalent Al(1)As4 tetrahedra. There are two inequivalent As sites. In the first As site, As(1) is bonded to three equivalent Ga(1) and one Al(1) atom to form AsAlGa3 tetrahedra that share corners with six equivalent As(2)Al3Ga tetrahedra and corners with six equivalent As(1)AlGa3 tetrahedra. In the second As site, As(2) is bonded to one Ga(1) and three equivalent Al(1) atoms to form AsAl3Ga tetrahedra that share corners with six equivalent As(2)Al3Ga tetrahedra and corners with six equivalent As(1)AlGa3 tetrahedra.
GaAlAs2 is Lavarevi\'{c}ite-like structured and crystallizes in the trigonal R3m space group. Ga(1) is bonded to one As(2) and three equivalent As(1) atoms to form GaAs4 tetrahedra that share corners with six equivalent Ga(1)As4 tetrahedra and corners with six equivalent Al(1)As4 tetrahedra. The Ga(1)-As(2) bond length is 2.46 Å. All Ga(1)-As(1) bond lengths are 2.46 Å. Al(1) is bonded to one As(1) and three equivalent As(2) atoms to form AlAs4 tetrahedra that share corners with six equivalent Ga(1)As4 tetrahedra and corners with six equivalent Al(1)As4 tetrahedra. The Al(1)-As(1) bond length is 2.46 Å. All Al(1)-As(2) bond lengths are 2.45 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded to three equivalent Ga(1) and one Al(1) atom to form AsAlGa3 tetrahedra that share corners with six equivalent As(2)Al3Ga tetrahedra and corners with six equivalent As(1)AlGa3 tetrahedra. In the second As site, As(2) is bonded to one Ga(1) and three equivalent Al(1) atoms to form AsAl3Ga tetrahedra that share corners with six equivalent As(2)Al3Ga tetrahedra and corners with six equivalent As(1)AlGa3 tetrahedra.