Pb4Si(OBr)4 crystallizes in the monoclinic P2_1/c space group. There are four inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a distorted L-shaped geometry to one O(1), one O(2), one Br(2), and two equivalent Br(3) atoms. In the second Pb site, Pb(2) is bonded in a distorted L-shaped geometry to one O(2), one O(3), one Br(1), one Br(2), and one Br(5) atom. In the third Pb site, Pb(3) is bonded in a 2-coordinate geometry to one O(1), one O(4), one Br(1), one Br(4), and two equivalent Br(2) atoms. In the fourth Pb site, Pb(4) is bonded in a 3-coordinate geometry to one O(3), two equivalent O(4), one Br(1), one Br(2), and one Br(5) atom. Si(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Pb(1), one Pb(3), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Pb(1), one Pb(2), and one Si(1) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Pb(2), one Pb(4), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Pb(3), two equivalent Pb(4), and one Si(1) atom. There are five inequivalent Br sites. In the first Br site, Br(5) is bonded in a 4-coordinate geometry to two equivalent Pb(2) and two equivalent Pb(4) atoms. In the second Br site, Br(1) is bonded in a T-shaped geometry to one Pb(2), one Pb(3), and one Pb(4) atom. In the third Br site, Br(2) is bonded in a 5-coordinate geometry to one Pb(1), one Pb(2), one Pb(4), and two equivalent Pb(3) atoms. In the fourth Br site, Br(3) is bonded in an L-shaped geometry to two equivalent Pb(1) atoms. In the fifth Br site, Br(4) is bonded in a linear geometry to two equivalent Pb(3) atoms.
Pb4Si(OBr)4 crystallizes in the monoclinic P2_1/c space group. There are four inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a distorted L-shaped geometry to one O(1), one O(2), one Br(2), and two equivalent Br(3) atoms. The Pb(1)-O(1) bond length is 2.32 Å. The Pb(1)-O(2) bond length is 2.33 Å. The Pb(1)-Br(2) bond length is 3.33 Å. There is one shorter (3.03 Å) and one longer (3.08 Å) Pb(1)-Br(3) bond length. In the second Pb site, Pb(2) is bonded in a distorted L-shaped geometry to one O(2), one O(3), one Br(1), one Br(2), and one Br(5) atom. The Pb(2)-O(2) bond length is 2.38 Å. The Pb(2)-O(3) bond length is 2.34 Å. The Pb(2)-Br(1) bond length is 2.99 Å. The Pb(2)-Br(2) bond length is 3.33 Å. The Pb(2)-Br(5) bond length is 3.40 Å. In the third Pb site, Pb(3) is bonded in a 2-coordinate geometry to one O(1), one O(4), one Br(1), one Br(4), and two equivalent Br(2) atoms. The Pb(3)-O(1) bond length is 2.40 Å. The Pb(3)-O(4) bond length is 2.61 Å. The Pb(3)-Br(1) bond length is 3.28 Å. The Pb(3)-Br(4) bond length is 3.08 Å. There is one shorter (3.19 Å) and one longer (3.43 Å) Pb(3)-Br(2) bond length. In the fourth Pb site, Pb(4) is bonded in a 3-coordinate geometry to one O(3), two equivalent O(4), one Br(1), one Br(2), and one Br(5) atom. The Pb(4)-O(3) bond length is 2.64 Å. There is one shorter (2.55 Å) and one longer (2.56 Å) Pb(4)-O(4) bond length. The Pb(4)-Br(1) bond length is 3.12 Å. The Pb(4)-Br(2) bond length is 3.21 Å. The Pb(4)-Br(5) bond length is 3.36 Å. Si(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. The Si(1)-O(1) bond length is 1.66 Å. The Si(1)-O(2) bond length is 1.65 Å. The Si(1)-O(3) bond length is 1.65 Å. The Si(1)-O(4) bond length is 1.66 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Pb(1), one Pb(3), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Pb(1), one Pb(2), and one Si(1) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Pb(2), one Pb(4), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Pb(3), two equivalent Pb(4), and one Si(1) atom. There are five inequivalent Br sites. In the first Br site, Br(5) is bonded in a 4-coordinate geometry to two equivalent Pb(2) and two equivalent Pb(4) atoms. In the second Br site, Br(1) is bonded in a T-shaped geometry to one Pb(2), one Pb(3), and one Pb(4) atom. In the third Br site, Br(2) is bonded in a 5-coordinate geometry to one Pb(1), one Pb(2), one Pb(4), and two equivalent Pb(3) atoms. In the fourth Br site, Br(3) is bonded in an L-shaped geometry to two equivalent Pb(1) atoms. In the fifth Br site, Br(4) is bonded in a linear geometry to two equivalent Pb(3) atoms.