Sr2YI7 crystallizes in the monoclinic P2_1 space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 7-coordinate geometry to one I(1), one I(11), one I(12), one I(14), one I(3), one I(8), and one I(9) atom. In the second Sr site, Sr(2) is bonded in a 7-coordinate geometry to one I(10), one I(13), one I(3), one I(4), one I(6), one I(7), and one I(9) atom. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to one I(1), one I(10), one I(14), one I(2), one I(4), one I(6), one I(8), and one I(9) atom. In the fourth Sr site, Sr(4) is bonded to one I(10), one I(11), one I(12), one I(13), one I(5), and one I(7) atom to form distorted SrI6 pentagonal pyramids that share  a cornercorner with one Y(1)I6 octahedra,  a cornercorner with one Y(2)I6 octahedra, and  a faceface with one Y(1)I6 octahedra. The corner-sharing octahedral tilt angles range from 60-63°. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to one I(11), one I(13), one I(3), one I(5), one I(6), and one I(7) atom to form YI6 octahedra that share  a cornercorner with one Sr(4)I6 pentagonal pyramid and  a faceface with one Sr(4)I6 pentagonal pyramid. In the second Y site, Y(2) is bonded to one I(1), one I(12), one I(14), one I(2), one I(4), and one I(8) atom to form YI6 octahedra that share  a cornercorner with one Sr(4)I6 pentagonal pyramid. There are fourteen inequivalent I sites. In the first I site, I(1) is bonded in a distorted L-shaped geometry to one Sr(1), one Sr(3), and one Y(2) atom. In the second I site, I(2) is bonded in an L-shaped geometry to one Sr(3) and one Y(2) atom. In the third I site, I(3) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(2), and one Y(1) atom. In the fourth I site, I(4) is bonded in a distorted trigonal planar geometry to one Sr(2), one Sr(3), and one Y(2) atom. In the fifth I site, I(5) is bonded in a bent 120 degrees geometry to one Sr(4) and one Y(1) atom. In the sixth I site, I(6) is bonded in a distorted trigonal non-coplanar geometry to one Sr(2), one Sr(3), and one Y(1) atom. In the seventh I site, I(7) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(4), and one Y(1) atom. In the eighth I site, I(8) is bonded in a distorted T-shaped geometry to one Sr(1), one Sr(3), and one Y(2) atom. In the ninth I site, I(9) is bonded in a trigonal non-coplanar geometry to one Sr(1), one Sr(2), and one Sr(3) atom. In the tenth I site, I(10) is bonded in a T-shaped geometry to one Sr(2), one Sr(3), and one Sr(4) atom. In the eleventh I site, I(11) is bonded in a distorted trigonal non-coplanar geometry to one Sr(1), one Sr(4), and one Y(1) atom. In the twelfth I site, I(12) is bonded in a distorted bent 120 degrees geometry to one Sr(1), one Sr(4), and one Y(2) atom. In the thirteenth I site, I(13) is bonded in a distorted T-shaped geometry to one Sr(2), one Sr(4), and one Y(1) atom. In the fourteenth I site, I(14) is bonded in a distorted trigonal non-coplanar geometry to one Sr(1), one Sr(3), and one Y(2) atom.
Sr2YI7 crystallizes in the monoclinic P2_1 space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 7-coordinate geometry to one I(1), one I(11), one I(12), one I(14), one I(3), one I(8), and one I(9) atom. The Sr(1)-I(1) bond length is 3.36 Å. The Sr(1)-I(11) bond length is 3.43 Å. The Sr(1)-I(12) bond length is 3.94 Å. The Sr(1)-I(14) bond length is 3.62 Å. The Sr(1)-I(3) bond length is 3.95 Å. The Sr(1)-I(8) bond length is 3.44 Å. The Sr(1)-I(9) bond length is 3.37 Å. In the second Sr site, Sr(2) is bonded in a 7-coordinate geometry to one I(10), one I(13), one I(3), one I(4), one I(6), one I(7), and one I(9) atom. The Sr(2)-I(10) bond length is 3.41 Å. The Sr(2)-I(13) bond length is 3.55 Å. The Sr(2)-I(3) bond length is 3.54 Å. The Sr(2)-I(4) bond length is 3.54 Å. The Sr(2)-I(6) bond length is 3.45 Å. The Sr(2)-I(7) bond length is 3.40 Å. The Sr(2)-I(9) bond length is 3.37 Å. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to one I(1), one I(10), one I(14), one I(2), one I(4), one I(6), one I(8), and one I(9) atom. The Sr(3)-I(1) bond length is 4.01 Å. The Sr(3)-I(10) bond length is 3.36 Å. The Sr(3)-I(14) bond length is 3.43 Å. The Sr(3)-I(2) bond length is 3.57 Å. The Sr(3)-I(4) bond length is 3.42 Å. The Sr(3)-I(6) bond length is 3.53 Å. The Sr(3)-I(8) bond length is 3.41 Å. The Sr(3)-I(9) bond length is 3.50 Å. In the fourth Sr site, Sr(4) is bonded to one I(10), one I(11), one I(12), one I(13), one I(5), and one I(7) atom to form distorted SrI6 pentagonal pyramids that share  a cornercorner with one Y(1)I6 octahedra,  a cornercorner with one Y(2)I6 octahedra, and  a faceface with one Y(1)I6 octahedra. The corner-sharing octahedral tilt angles range from 60-63°. The Sr(4)-I(10) bond length is 3.36 Å. The Sr(4)-I(11) bond length is 3.48 Å. The Sr(4)-I(12) bond length is 3.28 Å. The Sr(4)-I(13) bond length is 3.30 Å. The Sr(4)-I(5) bond length is 3.46 Å. The Sr(4)-I(7) bond length is 3.56 Å. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to one I(11), one I(13), one I(3), one I(5), one I(6), and one I(7) atom to form YI6 octahedra that share  a cornercorner with one Sr(4)I6 pentagonal pyramid and  a faceface with one Sr(4)I6 pentagonal pyramid. The Y(1)-I(11) bond length is 3.08 Å. The Y(1)-I(13) bond length is 3.10 Å. The Y(1)-I(3) bond length is 2.98 Å. The Y(1)-I(5) bond length is 3.02 Å. The Y(1)-I(6) bond length is 3.04 Å. The Y(1)-I(7) bond length is 3.05 Å. In the second Y site, Y(2) is bonded to one I(1), one I(12), one I(14), one I(2), one I(4), and one I(8) atom to form YI6 octahedra that share  a cornercorner with one Sr(4)I6 pentagonal pyramid. The Y(2)-I(1) bond length is 3.01 Å. The Y(2)-I(12) bond length is 3.03 Å. The Y(2)-I(14) bond length is 3.06 Å. The Y(2)-I(2) bond length is 2.99 Å. The Y(2)-I(4) bond length is 3.04 Å. The Y(2)-I(8) bond length is 3.11 Å. There are fourteen inequivalent I sites. In the first I site, I(1) is bonded in a distorted L-shaped geometry to one Sr(1), one Sr(3), and one Y(2) atom. In the second I site, I(2) is bonded in an L-shaped geometry to one Sr(3) and one Y(2) atom. In the third I site, I(3) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(2), and one Y(1) atom. In the fourth I site, I(4) is bonded in a distorted trigonal planar geometry to one Sr(2), one Sr(3), and one Y(2) atom. In the fifth I site, I(5) is bonded in a bent 120 degrees geometry to one Sr(4) and one Y(1) atom. In the sixth I site, I(6) is bonded in a distorted trigonal non-coplanar geometry to one Sr(2), one Sr(3), and one Y(1) atom. In the seventh I site, I(7) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(4), and one Y(1) atom. In the eighth I site, I(8) is bonded in a distorted T-shaped geometry to one Sr(1), one Sr(3), and one Y(2) atom. In the ninth I site, I(9) is bonded in a trigonal non-coplanar geometry to one Sr(1), one Sr(2), and one Sr(3) atom. In the tenth I site, I(10) is bonded in a T-shaped geometry to one Sr(2), one Sr(3), and one Sr(4) atom. In the eleventh I site, I(11) is bonded in a distorted trigonal non-coplanar geometry to one Sr(1), one Sr(4), and one Y(1) atom. In the twelfth I site, I(12) is bonded in a distorted bent 120 degrees geometry to one Sr(1), one Sr(4), and one Y(2) atom. In the thirteenth I site, I(13) is bonded in a distorted T-shaped geometry to one Sr(2), one Sr(4), and one Y(1) atom. In the fourteenth I site, I(14) is bonded in a distorted trigonal non-coplanar geometry to one Sr(1), one Sr(3), and one Y(2) atom.