Yb5Al17(Fe2Si3)2 crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 9-coordinate geometry to two equivalent Al(2), four equivalent Al(3), four equivalent Al(4), and one Si(2) atom. In the second Yb site, Yb(2) is bonded in a 8-coordinate geometry to eight equivalent Si(1) atoms. Fe(1) is bonded in a 9-coordinate geometry to two equivalent Al(1), four equivalent Al(3), one Si(2), and two equivalent Si(1) atoms. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded in a 2-coordinate geometry to two equivalent Fe(1), two equivalent Al(4), and four equivalent Al(3) atoms. In the second Al site, Al(2) is bonded to eight equivalent Yb(1) and four equivalent Al(4) atoms to form AlYb8Al4 cuboctahedra that share corners with eight equivalent Si(2)Yb2Al8Fe2 cuboctahedra and faces with two equivalent Al(2)Yb8Al4 cuboctahedra. In the third Al site, Al(3) is bonded in a 12-coordinate geometry to two equivalent Yb(1), two equivalent Fe(1), one Al(4), two equivalent Al(1), two equivalent Al(3), one Si(1), and two equivalent Si(2) atoms. In the fourth Al site, Al(4) is bonded in a 9-coordinate geometry to four equivalent Yb(1), one Al(2), two equivalent Al(1), and two equivalent Al(3) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 6-coordinate geometry to two equivalent Yb(2), two equivalent Fe(1), and two equivalent Al(3) atoms. In the second Si site, Si(2) is bonded to two equivalent Yb(1), two equivalent Fe(1), and eight equivalent Al(3) atoms to form SiYb2Al8Fe2 cuboctahedra that share corners with four equivalent Al(2)Yb8Al4 cuboctahedra and faces with two equivalent Si(2)Yb2Al8Fe2 cuboctahedra.
Yb5Al17(Fe2Si3)2 crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 9-coordinate geometry to two equivalent Al(2), four equivalent Al(3), four equivalent Al(4), and one Si(2) atom. Both Yb(1)-Al(2) bond lengths are 3.45 Å. All Yb(1)-Al(3) bond lengths are 3.01 Å. All Yb(1)-Al(4) bond lengths are 2.94 Å. The Yb(1)-Si(2) bond length is 2.99 Å. In the second Yb site, Yb(2) is bonded in a 8-coordinate geometry to eight equivalent Si(1) atoms. All Yb(2)-Si(1) bond lengths are 2.90 Å. Fe(1) is bonded in a 9-coordinate geometry to two equivalent Al(1), four equivalent Al(3), one Si(2), and two equivalent Si(1) atoms. Both Fe(1)-Al(1) bond lengths are 2.59 Å. All Fe(1)-Al(3) bond lengths are 2.55 Å. The Fe(1)-Si(2) bond length is 2.36 Å. Both Fe(1)-Si(1) bond lengths are 2.42 Å. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded in a 2-coordinate geometry to two equivalent Fe(1), two equivalent Al(4), and four equivalent Al(3) atoms. Both Al(1)-Al(4) bond lengths are 2.88 Å. All Al(1)-Al(3) bond lengths are 3.00 Å. In the second Al site, Al(2) is bonded to eight equivalent Yb(1) and four equivalent Al(4) atoms to form AlYb8Al4 cuboctahedra that share corners with eight equivalent Si(2)Yb2Al8Fe2 cuboctahedra and faces with two equivalent Al(2)Yb8Al4 cuboctahedra. All Al(2)-Al(4) bond lengths are 2.80 Å. In the third Al site, Al(3) is bonded in a 12-coordinate geometry to two equivalent Yb(1), two equivalent Fe(1), one Al(4), two equivalent Al(1), two equivalent Al(3), one Si(1), and two equivalent Si(2) atoms. The Al(3)-Al(4) bond length is 2.56 Å. There is one shorter (2.60 Å) and one longer (2.96 Å) Al(3)-Al(3) bond length. The Al(3)-Si(1) bond length is 2.58 Å. Both Al(3)-Si(2) bond lengths are 2.82 Å. In the fourth Al site, Al(4) is bonded in a 9-coordinate geometry to four equivalent Yb(1), one Al(2), two equivalent Al(1), and two equivalent Al(3) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 6-coordinate geometry to two equivalent Yb(2), two equivalent Fe(1), and two equivalent Al(3) atoms. In the second Si site, Si(2) is bonded to two equivalent Yb(1), two equivalent Fe(1), and eight equivalent Al(3) atoms to form SiYb2Al8Fe2 cuboctahedra that share corners with four equivalent Al(2)Yb8Al4 cuboctahedra and faces with two equivalent Si(2)Yb2Al8Fe2 cuboctahedra.