Sr2NiO3Cl crystallizes in the orthorhombic Pmma space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to two equivalent O(1), three equivalent O(2), and four equivalent O(3) atoms. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to two equivalent O(2), three equivalent O(1), and four equivalent O(3) atoms. In the third Sr site, Sr(3) is bonded in a 9-coordinate geometry to four equivalent O(3), two equivalent Cl(1), and three equivalent Cl(2) atoms. In the fourth Sr site, Sr(4) is bonded in a 9-coordinate geometry to four equivalent O(3), two equivalent Cl(2), and three equivalent Cl(1) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2) and four equivalent O(3) atoms to form corner-sharing NiO5 square pyramids. In the second Ni site, Ni(2) is bonded to one O(1) and four equivalent O(3) atoms to form corner-sharing NiO5 square pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), three equivalent Sr(2), and one Ni(2) atom to form distorted OSr5Ni octahedra that share corners with four equivalent O(1)Sr5Ni octahedra, corners with twelve equivalent O(3)Sr4Ni2 octahedra, edges with two equivalent O(1)Sr5Ni octahedra, edges with six equivalent O(2)Sr5Ni octahedra, and faces with four equivalent O(3)Sr4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 14-55°. In the second O site, O(2) is bonded to two equivalent Sr(2), three equivalent Sr(1), and one Ni(1) atom to form distorted OSr5Ni octahedra that share corners with four equivalent O(2)Sr5Ni octahedra, corners with twelve equivalent O(3)Sr4Ni2 octahedra, edges with two equivalent O(2)Sr5Ni octahedra, edges with six equivalent O(1)Sr5Ni octahedra, and faces with four equivalent O(3)Sr4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 12-54°. In the third O site, O(3) is bonded to one Sr(1), one Sr(2), one Sr(3), one Sr(4), one Ni(1), and one Ni(2) atom to form distorted OSr4Ni2 octahedra that share corners with two equivalent O(3)Sr4Ni2 octahedra, corners with three equivalent O(1)Sr5Ni octahedra, corners with three equivalent O(2)Sr5Ni octahedra, edges with two equivalent O(3)Sr4Ni2 octahedra,  a faceface with one O(1)Sr5Ni octahedra,  a faceface with one O(2)Sr5Ni octahedra, and faces with four equivalent O(3)Sr4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 17-55°. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a 5-coordinate geometry to two equivalent Sr(3) and three equivalent Sr(4) atoms. In the second Cl site, Cl(2) is bonded in a 5-coordinate geometry to two equivalent Sr(4) and three equivalent Sr(3) atoms.
Sr2NiO3Cl crystallizes in the orthorhombic Pmma space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to two equivalent O(1), three equivalent O(2), and four equivalent O(3) atoms. Both Sr(1)-O(1) bond lengths are 2.77 Å. There is one shorter (2.49 Å) and two longer (2.76 Å) Sr(1)-O(2) bond lengths. All Sr(1)-O(3) bond lengths are 2.76 Å. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to two equivalent O(2), three equivalent O(1), and four equivalent O(3) atoms. Both Sr(2)-O(2) bond lengths are 2.76 Å. There is one shorter (2.44 Å) and two longer (2.77 Å) Sr(2)-O(1) bond lengths. All Sr(2)-O(3) bond lengths are 2.76 Å. In the third Sr site, Sr(3) is bonded in a 9-coordinate geometry to four equivalent O(3), two equivalent Cl(1), and three equivalent Cl(2) atoms. All Sr(3)-O(3) bond lengths are 2.56 Å. Both Sr(3)-Cl(1) bond lengths are 2.98 Å. There are two shorter (3.01 Å) and one longer (3.47 Å) Sr(3)-Cl(2) bond length. In the fourth Sr site, Sr(4) is bonded in a 9-coordinate geometry to four equivalent O(3), two equivalent Cl(2), and three equivalent Cl(1) atoms. All Sr(4)-O(3) bond lengths are 2.56 Å. Both Sr(4)-Cl(2) bond lengths are 3.01 Å. There are two shorter (2.98 Å) and one longer (3.53 Å) Sr(4)-Cl(1) bond length. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2) and four equivalent O(3) atoms to form corner-sharing NiO5 square pyramids. The Ni(1)-O(2) bond length is 1.97 Å. All Ni(1)-O(3) bond lengths are 1.91 Å. In the second Ni site, Ni(2) is bonded to one O(1) and four equivalent O(3) atoms to form corner-sharing NiO5 square pyramids. The Ni(2)-O(1) bond length is 1.94 Å. All Ni(2)-O(3) bond lengths are 2.04 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), three equivalent Sr(2), and one Ni(2) atom to form distorted OSr5Ni octahedra that share corners with four equivalent O(1)Sr5Ni octahedra, corners with twelve equivalent O(3)Sr4Ni2 octahedra, edges with two equivalent O(1)Sr5Ni octahedra, edges with six equivalent O(2)Sr5Ni octahedra, and faces with four equivalent O(3)Sr4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 14-55°. In the second O site, O(2) is bonded to two equivalent Sr(2), three equivalent Sr(1), and one Ni(1) atom to form distorted OSr5Ni octahedra that share corners with four equivalent O(2)Sr5Ni octahedra, corners with twelve equivalent O(3)Sr4Ni2 octahedra, edges with two equivalent O(2)Sr5Ni octahedra, edges with six equivalent O(1)Sr5Ni octahedra, and faces with four equivalent O(3)Sr4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 12-54°. In the third O site, O(3) is bonded to one Sr(1), one Sr(2), one Sr(3), one Sr(4), one Ni(1), and one Ni(2) atom to form distorted OSr4Ni2 octahedra that share corners with two equivalent O(3)Sr4Ni2 octahedra, corners with three equivalent O(1)Sr5Ni octahedra, corners with three equivalent O(2)Sr5Ni octahedra, edges with two equivalent O(3)Sr4Ni2 octahedra,  a faceface with one O(1)Sr5Ni octahedra,  a faceface with one O(2)Sr5Ni octahedra, and faces with four equivalent O(3)Sr4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 17-55°. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a 5-coordinate geometry to two equivalent Sr(3) and three equivalent Sr(4) atoms. In the second Cl site, Cl(2) is bonded in a 5-coordinate geometry to two equivalent Sr(4) and three equivalent Sr(3) atoms.