Ba(Pt2As3)2 crystallizes in the monoclinic C2/c space group. Ba(1) is bonded in a 6-coordinate geometry to two equivalent Pt(2), four equivalent Pt(1), and four equivalent As(1) atoms. There are three inequivalent Pt sites. In the first Pt site, Pt(3) is bonded to two equivalent As(1), two equivalent As(2), and two equivalent As(3) atoms to form PtAs6 octahedra that share corners with four equivalent Pt(2)Ba2As4 octahedra, corners with eight equivalent Pt(1)Ba2As4 octahedra, corners with two equivalent As(2)AsPt3 tetrahedra, and corners with two equivalent As(3)AsPt3 tetrahedra. The corner-sharing octahedral tilt angles range from 60-65°. In the second Pt site, Pt(1) is bonded to two equivalent Ba(1), one As(2), one As(3), and two equivalent As(1) atoms to form PtBa2As4 octahedra that share corners with two equivalent Pt(2)Ba2As4 octahedra, corners with four equivalent Pt(3)As6 octahedra, corners with four equivalent Pt(1)Ba2As4 octahedra,  a cornercorner with one As(2)AsPt3 tetrahedra,  a cornercorner with one As(3)AsPt3 tetrahedra, edges with two equivalent Pt(1)Ba2As4 octahedra, and edges with two equivalent Pt(2)Ba2As4 octahedra. The corner-sharing octahedral tilt angles range from 22-109°. In the third Pt site, Pt(2) is bonded to two equivalent Ba(1), two equivalent As(2), and two equivalent As(3) atoms to form PtBa2As4 octahedra that share corners with two equivalent Pt(2)Ba2As4 octahedra, corners with four equivalent Pt(3)As6 octahedra, corners with four equivalent Pt(1)Ba2As4 octahedra, corners with two equivalent As(2)AsPt3 tetrahedra, corners with two equivalent As(3)AsPt3 tetrahedra, and edges with four equivalent Pt(1)Ba2As4 octahedra. The corner-sharing octahedral tilt angles range from 33-82°. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 6-coordinate geometry to two equivalent Ba(1), one Pt(3), two equivalent Pt(1), and one As(1) atom. In the second As site, As(2) is bonded to one Pt(1), one Pt(2), one Pt(3), and one As(2) atom to form distorted AsAsPt3 tetrahedra that share  a cornercorner with one Pt(3)As6 octahedra,  a cornercorner with one Pt(1)Ba2As4 octahedra,  a cornercorner with one Pt(2)Ba2As4 octahedra, corners with two equivalent As(2)AsPt3 tetrahedra, and corners with five equivalent As(3)AsPt3 tetrahedra. The corner-sharing octahedral tilt angles range from 73-78°. In the third As site, As(3) is bonded to one Pt(1), one Pt(2), one Pt(3), and one As(3) atom to form distorted AsAsPt3 tetrahedra that share  a cornercorner with one Pt(3)As6 octahedra,  a cornercorner with one Pt(1)Ba2As4 octahedra,  a cornercorner with one Pt(2)Ba2As4 octahedra, corners with two equivalent As(3)AsPt3 tetrahedra, and corners with five equivalent As(2)AsPt3 tetrahedra. The corner-sharing octahedral tilt angles range from 74-77°.
Ba(Pt2As3)2 crystallizes in the monoclinic C2/c space group. Ba(1) is bonded in a 6-coordinate geometry to two equivalent Pt(2), four equivalent Pt(1), and four equivalent As(1) atoms. Both Ba(1)-Pt(2) bond lengths are 3.15 Å. There are two shorter (2.98 Å) and two longer (3.21 Å) Ba(1)-Pt(1) bond lengths. There are two shorter (3.52 Å) and two longer (3.71 Å) Ba(1)-As(1) bond lengths. There are three inequivalent Pt sites. In the first Pt site, Pt(3) is bonded to two equivalent As(1), two equivalent As(2), and two equivalent As(3) atoms to form PtAs6 octahedra that share corners with four equivalent Pt(2)Ba2As4 octahedra, corners with eight equivalent Pt(1)Ba2As4 octahedra, corners with two equivalent As(2)AsPt3 tetrahedra, and corners with two equivalent As(3)AsPt3 tetrahedra. The corner-sharing octahedral tilt angles range from 60-65°. Both Pt(3)-As(1) bond lengths are 2.52 Å. Both Pt(3)-As(2) bond lengths are 2.53 Å. Both Pt(3)-As(3) bond lengths are 2.52 Å. In the second Pt site, Pt(1) is bonded to two equivalent Ba(1), one As(2), one As(3), and two equivalent As(1) atoms to form PtBa2As4 octahedra that share corners with two equivalent Pt(2)Ba2As4 octahedra, corners with four equivalent Pt(3)As6 octahedra, corners with four equivalent Pt(1)Ba2As4 octahedra,  a cornercorner with one As(2)AsPt3 tetrahedra,  a cornercorner with one As(3)AsPt3 tetrahedra, edges with two equivalent Pt(1)Ba2As4 octahedra, and edges with two equivalent Pt(2)Ba2As4 octahedra. The corner-sharing octahedral tilt angles range from 22-109°. The Pt(1)-As(2) bond length is 2.47 Å. The Pt(1)-As(3) bond length is 2.50 Å. There is one shorter (2.53 Å) and one longer (2.54 Å) Pt(1)-As(1) bond length. In the third Pt site, Pt(2) is bonded to two equivalent Ba(1), two equivalent As(2), and two equivalent As(3) atoms to form PtBa2As4 octahedra that share corners with two equivalent Pt(2)Ba2As4 octahedra, corners with four equivalent Pt(3)As6 octahedra, corners with four equivalent Pt(1)Ba2As4 octahedra, corners with two equivalent As(2)AsPt3 tetrahedra, corners with two equivalent As(3)AsPt3 tetrahedra, and edges with four equivalent Pt(1)Ba2As4 octahedra. The corner-sharing octahedral tilt angles range from 33-82°. Both Pt(2)-As(2) bond lengths are 2.52 Å. Both Pt(2)-As(3) bond lengths are 2.46 Å. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 6-coordinate geometry to two equivalent Ba(1), one Pt(3), two equivalent Pt(1), and one As(1) atom. The As(1)-As(1) bond length is 2.47 Å. In the second As site, As(2) is bonded to one Pt(1), one Pt(2), one Pt(3), and one As(2) atom to form distorted AsAsPt3 tetrahedra that share  a cornercorner with one Pt(3)As6 octahedra,  a cornercorner with one Pt(1)Ba2As4 octahedra,  a cornercorner with one Pt(2)Ba2As4 octahedra, corners with two equivalent As(2)AsPt3 tetrahedra, and corners with five equivalent As(3)AsPt3 tetrahedra. The corner-sharing octahedral tilt angles range from 73-78°. The As(2)-As(2) bond length is 2.45 Å. In the third As site, As(3) is bonded to one Pt(1), one Pt(2), one Pt(3), and one As(3) atom to form distorted AsAsPt3 tetrahedra that share  a cornercorner with one Pt(3)As6 octahedra,  a cornercorner with one Pt(1)Ba2As4 octahedra,  a cornercorner with one Pt(2)Ba2As4 octahedra, corners with two equivalent As(3)AsPt3 tetrahedra, and corners with five equivalent As(2)AsPt3 tetrahedra. The corner-sharing octahedral tilt angles range from 74-77°. The As(3)-As(3) bond length is 2.44 Å.