In3Al(CuSe2)4 is Stannite-like structured and crystallizes in the triclinic P1 space group. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Se(1), one Se(4), one Se(5), and one Se(7) atom to form CuSe4 tetrahedra that share  a cornercorner with one Cu(4)Se4 tetrahedra,  a cornercorner with one In(3)Se4 tetrahedra, corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent Al(1)Se4 tetrahedra, corners with three equivalent Cu(3)Se4 tetrahedra, and corners with three equivalent In(2)Se4 tetrahedra. In the second Cu site, Cu(2) is bonded to one Se(2), one Se(3), one Se(6), and one Se(8) atom to form CuSe4 tetrahedra that share  a cornercorner with one Cu(3)Se4 tetrahedra,  a cornercorner with one In(2)Se4 tetrahedra, corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent Al(1)Se4 tetrahedra, corners with three equivalent Cu(4)Se4 tetrahedra, and corners with three equivalent In(3)Se4 tetrahedra. In the third Cu site, Cu(3) is bonded to one Se(1), one Se(4), one Se(5), and one Se(8) atom to form CuSe4 tetrahedra that share  a cornercorner with one Cu(2)Se4 tetrahedra,  a cornercorner with one In(1)Se4 tetrahedra, corners with two equivalent In(2)Se4 tetrahedra, corners with two equivalent In(3)Se4 tetrahedra, corners with three equivalent Cu(1)Se4 tetrahedra, and corners with three equivalent Al(1)Se4 tetrahedra. In the fourth Cu site, Cu(4) is bonded to one Se(2), one Se(3), one Se(6), and one Se(7) atom to form CuSe4 tetrahedra that share  a cornercorner with one Cu(1)Se4 tetrahedra,  a cornercorner with one Al(1)Se4 tetrahedra, corners with two equivalent In(2)Se4 tetrahedra, corners with two equivalent In(3)Se4 tetrahedra, corners with three equivalent Cu(2)Se4 tetrahedra, and corners with three equivalent In(1)Se4 tetrahedra. There are three inequivalent In sites. In the first In site, In(1) is bonded to one Se(2), one Se(4), one Se(6), and one Se(7) atom to form InSe4 tetrahedra that share  a cornercorner with one Cu(3)Se4 tetrahedra,  a cornercorner with one In(3)Se4 tetrahedra, corners with two equivalent Cu(1)Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, corners with three equivalent Cu(4)Se4 tetrahedra, and corners with three equivalent In(2)Se4 tetrahedra. In the second In site, In(2) is bonded to one Se(2), one Se(4), one Se(5), and one Se(7) atom to form InSe4 tetrahedra that share  a cornercorner with one Cu(2)Se4 tetrahedra,  a cornercorner with one Al(1)Se4 tetrahedra, corners with two equivalent Cu(3)Se4 tetrahedra, corners with two equivalent Cu(4)Se4 tetrahedra, corners with three equivalent Cu(1)Se4 tetrahedra, and corners with three equivalent In(1)Se4 tetrahedra. In the third In site, In(3) is bonded to one Se(1), one Se(3), one Se(6), and one Se(8) atom to form InSe4 tetrahedra that share  a cornercorner with one Cu(1)Se4 tetrahedra,  a cornercorner with one In(1)Se4 tetrahedra, corners with two equivalent Cu(3)Se4 tetrahedra, corners with two equivalent Cu(4)Se4 tetrahedra, corners with three equivalent Cu(2)Se4 tetrahedra, and corners with three equivalent Al(1)Se4 tetrahedra. Al(1) is bonded to one Se(1), one Se(3), one Se(5), and one Se(8) atom to form AlSe4 tetrahedra that share  a cornercorner with one Cu(4)Se4 tetrahedra,  a cornercorner with one In(2)Se4 tetrahedra, corners with two equivalent Cu(1)Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, corners with three equivalent Cu(3)Se4 tetrahedra, and corners with three equivalent In(3)Se4 tetrahedra. There are eight inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cu(1), one Cu(3), one In(3), and one Al(1) atom to form SeAlInCu2 tetrahedra that share  a cornercorner with one Se(6)In2Cu2 tetrahedra,  a cornercorner with one Se(7)In2Cu2 tetrahedra, corners with two equivalent Se(3)AlInCu2 tetrahedra, corners with two equivalent Se(4)In2Cu2 tetrahedra, corners with three equivalent Se(5)AlInCu2 tetrahedra, and corners with three equivalent Se(8)AlInCu2 tetrahedra. In the second Se site, Se(2) is bonded to one Cu(2), one Cu(4), one In(1), and one In(2) atom to form SeIn2Cu2 tetrahedra that share  a cornercorner with one Se(5)AlInCu2 tetrahedra,  a cornercorner with one Se(8)AlInCu2 tetrahedra, corners with two equivalent Se(3)AlInCu2 tetrahedra, corners with two equivalent Se(4)In2Cu2 tetrahedra, corners with three equivalent Se(6)In2Cu2 tetrahedra, and corners with three equivalent Se(7)In2Cu2 tetrahedra. In the third Se site, Se(3) is bonded to one Cu(2), one Cu(4), one In(3), and one Al(1) atom to form SeAlInCu2 tetrahedra that share  a cornercorner with one Se(5)AlInCu2 tetrahedra,  a cornercorner with one Se(7)In2Cu2 tetrahedra, corners with two equivalent Se(1)AlInCu2 tetrahedra, corners with two equivalent Se(2)In2Cu2 tetrahedra, corners with three equivalent Se(8)AlInCu2 tetrahedra, and corners with three equivalent Se(6)In2Cu2 tetrahedra. In the fourth Se site, Se(4) is bonded to one Cu(1), one Cu(3), one In(1), and one In(2) atom to form SeIn2Cu2 tetrahedra that share  a cornercorner with one Se(8)AlInCu2 tetrahedra,  a cornercorner with one Se(6)In2Cu2 tetrahedra, corners with two equivalent Se(1)AlInCu2 tetrahedra, corners with two equivalent Se(2)In2Cu2 tetrahedra, corners with three equivalent Se(5)AlInCu2 tetrahedra, and corners with three equivalent Se(7)In2Cu2 tetrahedra. In the fifth Se site, Se(5) is bonded to one Cu(1), one Cu(3), one In(2), and one Al(1) atom to form SeAlInCu2 tetrahedra that share  a cornercorner with one Se(3)AlInCu2 tetrahedra,  a cornercorner with one Se(2)In2Cu2 tetrahedra, corners with two equivalent Se(8)AlInCu2 tetrahedra, corners with two equivalent Se(7)In2Cu2 tetrahedra, corners with three equivalent Se(1)AlInCu2 tetrahedra, and corners with three equivalent Se(4)In2Cu2 tetrahedra. In the sixth Se site, Se(6) is bonded to one Cu(2), one Cu(4), one In(1), and one In(3) atom to form SeIn2Cu2 tetrahedra that share  a cornercorner with one Se(1)AlInCu2 tetrahedra,  a cornercorner with one Se(4)In2Cu2 tetrahedra, corners with two equivalent Se(8)AlInCu2 tetrahedra, corners with two equivalent Se(7)In2Cu2 tetrahedra, corners with three equivalent Se(3)AlInCu2 tetrahedra, and corners with three equivalent Se(2)In2Cu2 tetrahedra. In the seventh Se site, Se(7) is bonded to one Cu(1), one Cu(4), one In(1), and one In(2) atom to form SeIn2Cu2 tetrahedra that share  a cornercorner with one Se(1)AlInCu2 tetrahedra,  a cornercorner with one Se(3)AlInCu2 tetrahedra, corners with two equivalent Se(5)AlInCu2 tetrahedra, corners with two equivalent Se(6)In2Cu2 tetrahedra, corners with three equivalent Se(2)In2Cu2 tetrahedra, and corners with three equivalent Se(4)In2Cu2 tetrahedra. In the eighth Se site, Se(8) is bonded to one Cu(2), one Cu(3), one In(3), and one Al(1) atom to form SeAlInCu2 tetrahedra that share  a cornercorner with one Se(2)In2Cu2 tetrahedra,  a cornercorner with one Se(4)In2Cu2 tetrahedra, corners with two equivalent Se(5)AlInCu2 tetrahedra, corners with two equivalent Se(6)In2Cu2 tetrahedra, corners with three equivalent Se(1)AlInCu2 tetrahedra, and corners with three equivalent Se(3)AlInCu2 tetrahedra.
In3Al(CuSe2)4 is Stannite-like structured and crystallizes in the triclinic P1 space group. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Se(1), one Se(4), one Se(5), and one Se(7) atom to form CuSe4 tetrahedra that share  a cornercorner with one Cu(4)Se4 tetrahedra,  a cornercorner with one In(3)Se4 tetrahedra, corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent Al(1)Se4 tetrahedra, corners with three equivalent Cu(3)Se4 tetrahedra, and corners with three equivalent In(2)Se4 tetrahedra. The Cu(1)-Se(1) bond length is 2.47 Å. The Cu(1)-Se(4) bond length is 2.43 Å. The Cu(1)-Se(5) bond length is 2.48 Å. The Cu(1)-Se(7) bond length is 2.43 Å. In the second Cu site, Cu(2) is bonded to one Se(2), one Se(3), one Se(6), and one Se(8) atom to form CuSe4 tetrahedra that share  a cornercorner with one Cu(3)Se4 tetrahedra,  a cornercorner with one In(2)Se4 tetrahedra, corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent Al(1)Se4 tetrahedra, corners with three equivalent Cu(4)Se4 tetrahedra, and corners with three equivalent In(3)Se4 tetrahedra. The Cu(2)-Se(2) bond length is 2.43 Å. The Cu(2)-Se(3) bond length is 2.47 Å. The Cu(2)-Se(6) bond length is 2.43 Å. The Cu(2)-Se(8) bond length is 2.47 Å. In the third Cu site, Cu(3) is bonded to one Se(1), one Se(4), one Se(5), and one Se(8) atom to form CuSe4 tetrahedra that share  a cornercorner with one Cu(2)Se4 tetrahedra,  a cornercorner with one In(1)Se4 tetrahedra, corners with two equivalent In(2)Se4 tetrahedra, corners with two equivalent In(3)Se4 tetrahedra, corners with three equivalent Cu(1)Se4 tetrahedra, and corners with three equivalent Al(1)Se4 tetrahedra. The Cu(3)-Se(1) bond length is 2.47 Å. The Cu(3)-Se(4) bond length is 2.42 Å. The Cu(3)-Se(5) bond length is 2.47 Å. The Cu(3)-Se(8) bond length is 2.47 Å. In the fourth Cu site, Cu(4) is bonded to one Se(2), one Se(3), one Se(6), and one Se(7) atom to form CuSe4 tetrahedra that share  a cornercorner with one Cu(1)Se4 tetrahedra,  a cornercorner with one Al(1)Se4 tetrahedra, corners with two equivalent In(2)Se4 tetrahedra, corners with two equivalent In(3)Se4 tetrahedra, corners with three equivalent Cu(2)Se4 tetrahedra, and corners with three equivalent In(1)Se4 tetrahedra. The Cu(4)-Se(2) bond length is 2.42 Å. The Cu(4)-Se(3) bond length is 2.46 Å. The Cu(4)-Se(6) bond length is 2.42 Å. The Cu(4)-Se(7) bond length is 2.42 Å. There are three inequivalent In sites. In the first In site, In(1) is bonded to one Se(2), one Se(4), one Se(6), and one Se(7) atom to form InSe4 tetrahedra that share  a cornercorner with one Cu(3)Se4 tetrahedra,  a cornercorner with one In(3)Se4 tetrahedra, corners with two equivalent Cu(1)Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, corners with three equivalent Cu(4)Se4 tetrahedra, and corners with three equivalent In(2)Se4 tetrahedra. The In(1)-Se(2) bond length is 2.64 Å. The In(1)-Se(4) bond length is 2.64 Å. The In(1)-Se(6) bond length is 2.64 Å. The In(1)-Se(7) bond length is 2.64 Å. In the second In site, In(2) is bonded to one Se(2), one Se(4), one Se(5), and one Se(7) atom to form InSe4 tetrahedra that share  a cornercorner with one Cu(2)Se4 tetrahedra,  a cornercorner with one Al(1)Se4 tetrahedra, corners with two equivalent Cu(3)Se4 tetrahedra, corners with two equivalent Cu(4)Se4 tetrahedra, corners with three equivalent Cu(1)Se4 tetrahedra, and corners with three equivalent In(1)Se4 tetrahedra. The In(2)-Se(2) bond length is 2.65 Å. The In(2)-Se(4) bond length is 2.64 Å. The In(2)-Se(5) bond length is 2.66 Å. The In(2)-Se(7) bond length is 2.64 Å. In the third In site, In(3) is bonded to one Se(1), one Se(3), one Se(6), and one Se(8) atom to form InSe4 tetrahedra that share  a cornercorner with one Cu(1)Se4 tetrahedra,  a cornercorner with one In(1)Se4 tetrahedra, corners with two equivalent Cu(3)Se4 tetrahedra, corners with two equivalent Cu(4)Se4 tetrahedra, corners with three equivalent Cu(2)Se4 tetrahedra, and corners with three equivalent Al(1)Se4 tetrahedra. The In(3)-Se(1) bond length is 2.67 Å. The In(3)-Se(3) bond length is 2.67 Å. The In(3)-Se(6) bond length is 2.65 Å. The In(3)-Se(8) bond length is 2.67 Å. Al(1) is bonded to one Se(1), one Se(3), one Se(5), and one Se(8) atom to form AlSe4 tetrahedra that share  a cornercorner with one Cu(4)Se4 tetrahedra,  a cornercorner with one In(2)Se4 tetrahedra, corners with two equivalent Cu(1)Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, corners with three equivalent Cu(3)Se4 tetrahedra, and corners with three equivalent In(3)Se4 tetrahedra. The Al(1)-Se(1) bond length is 2.45 Å. The Al(1)-Se(3) bond length is 2.45 Å. The Al(1)-Se(5) bond length is 2.45 Å. The Al(1)-Se(8) bond length is 2.45 Å. There are eight inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cu(1), one Cu(3), one In(3), and one Al(1) atom to form SeAlInCu2 tetrahedra that share  a cornercorner with one Se(6)In2Cu2 tetrahedra,  a cornercorner with one Se(7)In2Cu2 tetrahedra, corners with two equivalent Se(3)AlInCu2 tetrahedra, corners with two equivalent Se(4)In2Cu2 tetrahedra, corners with three equivalent Se(5)AlInCu2 tetrahedra, and corners with three equivalent Se(8)AlInCu2 tetrahedra. In the second Se site, Se(2) is bonded to one Cu(2), one Cu(4), one In(1), and one In(2) atom to form SeIn2Cu2 tetrahedra that share  a cornercorner with one Se(5)AlInCu2 tetrahedra,  a cornercorner with one Se(8)AlInCu2 tetrahedra, corners with two equivalent Se(3)AlInCu2 tetrahedra, corners with two equivalent Se(4)In2Cu2 tetrahedra, corners with three equivalent Se(6)In2Cu2 tetrahedra, and corners with three equivalent Se(7)In2Cu2 tetrahedra. In the third Se site, Se(3) is bonded to one Cu(2), one Cu(4), one In(3), and one Al(1) atom to form SeAlInCu2 tetrahedra that share  a cornercorner with one Se(5)AlInCu2 tetrahedra,  a cornercorner with one Se(7)In2Cu2 tetrahedra, corners with two equivalent Se(1)AlInCu2 tetrahedra, corners with two equivalent Se(2)In2Cu2 tetrahedra, corners with three equivalent Se(8)AlInCu2 tetrahedra, and corners with three equivalent Se(6)In2Cu2 tetrahedra. In the fourth Se site, Se(4) is bonded to one Cu(1), one Cu(3), one In(1), and one In(2) atom to form SeIn2Cu2 tetrahedra that share  a cornercorner with one Se(8)AlInCu2 tetrahedra,  a cornercorner with one Se(6)In2Cu2 tetrahedra, corners with two equivalent Se(1)AlInCu2 tetrahedra, corners with two equivalent Se(2)In2Cu2 tetrahedra, corners with three equivalent Se(5)AlInCu2 tetrahedra, and corners with three equivalent Se(7)In2Cu2 tetrahedra. In the fifth Se site, Se(5) is bonded to one Cu(1), one Cu(3), one In(2), and one Al(1) atom to form SeAlInCu2 tetrahedra that share  a cornercorner with one Se(3)AlInCu2 tetrahedra,  a cornercorner with one Se(2)In2Cu2 tetrahedra, corners with two equivalent Se(8)AlInCu2 tetrahedra, corners with two equivalent Se(7)In2Cu2 tetrahedra, corners with three equivalent Se(1)AlInCu2 tetrahedra, and corners with three equivalent Se(4)In2Cu2 tetrahedra. In the sixth Se site, Se(6) is bonded to one Cu(2), one Cu(4), one In(1), and one In(3) atom to form SeIn2Cu2 tetrahedra that share  a cornercorner with one Se(1)AlInCu2 tetrahedra,  a cornercorner with one Se(4)In2Cu2 tetrahedra, corners with two equivalent Se(8)AlInCu2 tetrahedra, corners with two equivalent Se(7)In2Cu2 tetrahedra, corners with three equivalent Se(3)AlInCu2 tetrahedra, and corners with three equivalent Se(2)In2Cu2 tetrahedra. In the seventh Se site, Se(7) is bonded to one Cu(1), one Cu(4), one In(1), and one In(2) atom to form SeIn2Cu2 tetrahedra that share  a cornercorner with one Se(1)AlInCu2 tetrahedra,  a cornercorner with one Se(3)AlInCu2 tetrahedra, corners with two equivalent Se(5)AlInCu2 tetrahedra, corners with two equivalent Se(6)In2Cu2 tetrahedra, corners with three equivalent Se(2)In2Cu2 tetrahedra, and corners with three equivalent Se(4)In2Cu2 tetrahedra. In the eighth Se site, Se(8) is bonded to one Cu(2), one Cu(3), one In(3), and one Al(1) atom to form SeAlInCu2 tetrahedra that share  a cornercorner with one Se(2)In2Cu2 tetrahedra,  a cornercorner with one Se(4)In2Cu2 tetrahedra, corners with two equivalent Se(5)AlInCu2 tetrahedra, corners with two equivalent Se(6)In2Cu2 tetrahedra, corners with three equivalent Se(1)AlInCu2 tetrahedra, and corners with three equivalent Se(3)AlInCu2 tetrahedra.