Na8BeAl4Si7(O12Br)2 crystallizes in the tetragonal P-4 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), one O(3), and one Br(1) atom to form NaBrO3 tetrahedra that share  a cornercorner with one Na(1)BrO3 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Na(2)BrO3 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. In the second Na site, Na(2) is bonded to one O(4), one O(5), one O(6), and one Br(1) atom to form distorted NaBrO3 tetrahedra that share  a cornercorner with one Na(2)BrO3 tetrahedra,  a cornercorner with one Be(1)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Na(1)BrO3 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. Be(1) is bonded to four equivalent O(4) atoms to form BeO4 tetrahedra that share corners with four equivalent Na(2)BrO3 tetrahedra and corners with four equivalent Si(3)O4 tetrahedra. Al(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Na(1)BrO3 tetrahedra, corners with two equivalent Na(2)BrO3 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to four equivalent O(3) atoms to form SiO4 tetrahedra that share corners with four equivalent Na(1)BrO3 tetrahedra and corners with four equivalent Si(3)O4 tetrahedra. In the second Si site, Si(2) is bonded to four equivalent O(1) atoms to form SiO4 tetrahedra that share corners with four equivalent Na(1)BrO3 tetrahedra and corners with four equivalent Al(1)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Be(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Na(1)BrO3 tetrahedra, corners with two equivalent Na(2)BrO3 tetrahedra, and corners with two equivalent Al(1)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to four equivalent O(6) atoms to form SiO4 tetrahedra that share corners with four equivalent Na(2)BrO3 tetrahedra and corners with four equivalent Al(1)O4 tetrahedra. There are six inequivalent O sites. In the first O site, O(4) is bonded in a 3-coordinate geometry to one Na(2), one Be(1), and one Si(3) atom. In the second O site, O(5) is bonded in a 3-coordinate geometry to one Na(2), one Al(1), and one Si(3) atom. In the third O site, O(6) is bonded in a 3-coordinate geometry to one Na(2), one Al(1), and one Si(4) atom. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Al(1), and one Si(2) atom. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Al(1), and one Si(3) atom. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(3) atom. Br(1) is bonded in a tetrahedral geometry to two equivalent Na(1) and two equivalent Na(2) atoms.
Na8BeAl4Si7(O12Br)2 crystallizes in the tetragonal P-4 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), one O(3), and one Br(1) atom to form NaBrO3 tetrahedra that share  a cornercorner with one Na(1)BrO3 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Na(2)BrO3 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The Na(1)-O(1) bond length is 2.39 Å. The Na(1)-O(2) bond length is 2.42 Å. The Na(1)-O(3) bond length is 2.55 Å. The Na(1)-Br(1) bond length is 2.97 Å. In the second Na site, Na(2) is bonded to one O(4), one O(5), one O(6), and one Br(1) atom to form distorted NaBrO3 tetrahedra that share  a cornercorner with one Na(2)BrO3 tetrahedra,  a cornercorner with one Be(1)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Na(1)BrO3 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The Na(2)-O(4) bond length is 2.37 Å. The Na(2)-O(5) bond length is 2.42 Å. The Na(2)-O(6) bond length is 2.53 Å. The Na(2)-Br(1) bond length is 3.11 Å. Be(1) is bonded to four equivalent O(4) atoms to form BeO4 tetrahedra that share corners with four equivalent Na(2)BrO3 tetrahedra and corners with four equivalent Si(3)O4 tetrahedra. All Be(1)-O(4) bond lengths are 1.64 Å. Al(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Na(1)BrO3 tetrahedra, corners with two equivalent Na(2)BrO3 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The Al(1)-O(1) bond length is 1.74 Å. The Al(1)-O(2) bond length is 1.76 Å. The Al(1)-O(5) bond length is 1.75 Å. The Al(1)-O(6) bond length is 1.74 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to four equivalent O(3) atoms to form SiO4 tetrahedra that share corners with four equivalent Na(1)BrO3 tetrahedra and corners with four equivalent Si(3)O4 tetrahedra. All Si(1)-O(3) bond lengths are 1.63 Å. In the second Si site, Si(2) is bonded to four equivalent O(1) atoms to form SiO4 tetrahedra that share corners with four equivalent Na(1)BrO3 tetrahedra and corners with four equivalent Al(1)O4 tetrahedra. All Si(2)-O(1) bond lengths are 1.63 Å. In the third Si site, Si(3) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Be(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Na(1)BrO3 tetrahedra, corners with two equivalent Na(2)BrO3 tetrahedra, and corners with two equivalent Al(1)O4 tetrahedra. The Si(3)-O(2) bond length is 1.63 Å. The Si(3)-O(3) bond length is 1.69 Å. The Si(3)-O(4) bond length is 1.60 Å. The Si(3)-O(5) bond length is 1.63 Å. In the fourth Si site, Si(4) is bonded to four equivalent O(6) atoms to form SiO4 tetrahedra that share corners with four equivalent Na(2)BrO3 tetrahedra and corners with four equivalent Al(1)O4 tetrahedra. All Si(4)-O(6) bond lengths are 1.63 Å. There are six inequivalent O sites. In the first O site, O(4) is bonded in a 3-coordinate geometry to one Na(2), one Be(1), and one Si(3) atom. In the second O site, O(5) is bonded in a 3-coordinate geometry to one Na(2), one Al(1), and one Si(3) atom. In the third O site, O(6) is bonded in a 3-coordinate geometry to one Na(2), one Al(1), and one Si(4) atom. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Al(1), and one Si(2) atom. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Al(1), and one Si(3) atom. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(3) atom. Br(1) is bonded in a tetrahedral geometry to two equivalent Na(1) and two equivalent Na(2) atoms.