Ba2AgSi3 is hexagonal omega structure-derived structured and crystallizes in the orthorhombic Fddd space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent Ag(1), two equivalent Si(2), and six equivalent Si(1) atoms to form BaSi8Ag4 cuboctahedra that share edges with six equivalent Ba(2)Si10Ag2 cuboctahedra, edges with six equivalent Ba(1)Si8Ag4 cuboctahedra, faces with three equivalent Ba(1)Si8Ag4 cuboctahedra, and faces with five equivalent Ba(2)Si10Ag2 cuboctahedra. In the second Ba site, Ba(2) is bonded to two equivalent Ag(1), four equivalent Si(2), and six equivalent Si(1) atoms to form BaSi10Ag2 cuboctahedra that share edges with six equivalent Ba(2)Si10Ag2 cuboctahedra, edges with six equivalent Ba(1)Si8Ag4 cuboctahedra, faces with three equivalent Ba(2)Si10Ag2 cuboctahedra, and faces with five equivalent Ba(1)Si8Ag4 cuboctahedra. Ag(1) is bonded in a 9-coordinate geometry to two equivalent Ba(2), four equivalent Ba(1), one Si(2), and two equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to three equivalent Ba(1), three equivalent Ba(2), one Ag(1), one Si(1), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Ba(1), four equivalent Ba(2), one Ag(1), and two equivalent Si(1) atoms.
Ba2AgSi3 is hexagonal omega structure-derived structured and crystallizes in the orthorhombic Fddd space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent Ag(1), two equivalent Si(2), and six equivalent Si(1) atoms to form BaSi8Ag4 cuboctahedra that share edges with six equivalent Ba(2)Si10Ag2 cuboctahedra, edges with six equivalent Ba(1)Si8Ag4 cuboctahedra, faces with three equivalent Ba(1)Si8Ag4 cuboctahedra, and faces with five equivalent Ba(2)Si10Ag2 cuboctahedra. There are two shorter (3.52 Å) and two longer (3.53 Å) Ba(1)-Ag(1) bond lengths. Both Ba(1)-Si(2) bond lengths are 3.57 Å. There are a spread of Ba(1)-Si(1) bond distances ranging from 3.52-3.60 Å. In the second Ba site, Ba(2) is bonded to two equivalent Ag(1), four equivalent Si(2), and six equivalent Si(1) atoms to form BaSi10Ag2 cuboctahedra that share edges with six equivalent Ba(2)Si10Ag2 cuboctahedra, edges with six equivalent Ba(1)Si8Ag4 cuboctahedra, faces with three equivalent Ba(2)Si10Ag2 cuboctahedra, and faces with five equivalent Ba(1)Si8Ag4 cuboctahedra. Both Ba(2)-Ag(1) bond lengths are 3.53 Å. There are two shorter (3.45 Å) and two longer (3.57 Å) Ba(2)-Si(2) bond lengths. There are a spread of Ba(2)-Si(1) bond distances ranging from 3.41-3.61 Å. Ag(1) is bonded in a 9-coordinate geometry to two equivalent Ba(2), four equivalent Ba(1), one Si(2), and two equivalent Si(1) atoms. The Ag(1)-Si(2) bond length is 2.59 Å. Both Ag(1)-Si(1) bond lengths are 2.60 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to three equivalent Ba(1), three equivalent Ba(2), one Ag(1), one Si(1), and one Si(2) atom. The Si(1)-Si(1) bond length is 2.39 Å. The Si(1)-Si(2) bond length is 2.39 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Ba(1), four equivalent Ba(2), one Ag(1), and two equivalent Si(1) atoms.