Eu2As3 is Magnesium tetraboride-like structured and crystallizes in the monoclinic P2/c space group. There are five inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 8-coordinate geometry to two equivalent As(1), two equivalent As(2), and four equivalent As(4) atoms. In the second Eu site, Eu(2) is bonded in a 8-coordinate geometry to one As(3), one As(4), one As(5), two equivalent As(6), and three equivalent As(2) atoms. In the third Eu site, Eu(3) is bonded in a 9-coordinate geometry to one As(2), one As(3), one As(5), two equivalent As(1), two equivalent As(4), and two equivalent As(6) atoms. In the fourth Eu site, Eu(4) is bonded in a 8-coordinate geometry to two equivalent As(1), two equivalent As(3), two equivalent As(6), and four equivalent As(5) atoms. In the fifth Eu site, Eu(5) is bonded to one As(2), one As(4), one As(5), two equivalent As(1), and three equivalent As(3) atoms to form a mixture of distorted edge, corner, and face-sharing EuAs8 hexagonal bipyramids. There are six inequivalent As sites. In the first As site, As(5) is bonded in a 7-coordinate geometry to one Eu(2), one Eu(3), one Eu(5), two equivalent Eu(4), one As(5), and one As(6) atom. In the second As site, As(6) is bonded in a 7-coordinate geometry to one Eu(4), two equivalent Eu(2), two equivalent Eu(3), one As(1), and one As(5) atom. In the third As site, As(1) is bonded in a 8-coordinate geometry to one Eu(1), one Eu(4), two equivalent Eu(3), two equivalent Eu(5), one As(3), and one As(6) atom. In the fourth As site, As(2) is bonded in a 7-coordinate geometry to one Eu(1), one Eu(3), one Eu(5), three equivalent Eu(2), and one As(4) atom. In the fifth As site, As(3) is bonded in a 7-coordinate geometry to one Eu(2), one Eu(3), one Eu(4), three equivalent Eu(5), and one As(1) atom. In the sixth As site, As(4) is bonded in a 8-coordinate geometry to one Eu(2), one Eu(5), two equivalent Eu(1), two equivalent Eu(3), one As(2), and one As(4) atom.
Eu2As3 is Magnesium tetraboride-like structured and crystallizes in the monoclinic P2/c space group. There are five inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 8-coordinate geometry to two equivalent As(1), two equivalent As(2), and four equivalent As(4) atoms. Both Eu(1)-As(1) bond lengths are 3.18 Å. Both Eu(1)-As(2) bond lengths are 3.15 Å. There are two shorter (3.23 Å) and two longer (3.31 Å) Eu(1)-As(4) bond lengths. In the second Eu site, Eu(2) is bonded in a 8-coordinate geometry to one As(3), one As(4), one As(5), two equivalent As(6), and three equivalent As(2) atoms. The Eu(2)-As(3) bond length is 3.44 Å. The Eu(2)-As(4) bond length is 3.13 Å. The Eu(2)-As(5) bond length is 3.36 Å. There is one shorter (3.18 Å) and one longer (3.20 Å) Eu(2)-As(6) bond length. There are a spread of Eu(2)-As(2) bond distances ranging from 3.14-3.42 Å. In the third Eu site, Eu(3) is bonded in a 9-coordinate geometry to one As(2), one As(3), one As(5), two equivalent As(1), two equivalent As(4), and two equivalent As(6) atoms. The Eu(3)-As(2) bond length is 3.10 Å. The Eu(3)-As(3) bond length is 3.15 Å. The Eu(3)-As(5) bond length is 3.14 Å. Both Eu(3)-As(1) bond lengths are 3.20 Å. There is one shorter (3.13 Å) and one longer (3.43 Å) Eu(3)-As(4) bond length. There is one shorter (3.09 Å) and one longer (3.64 Å) Eu(3)-As(6) bond length. In the fourth Eu site, Eu(4) is bonded in a 8-coordinate geometry to two equivalent As(1), two equivalent As(3), two equivalent As(6), and four equivalent As(5) atoms. Both Eu(4)-As(1) bond lengths are 3.52 Å. Both Eu(4)-As(3) bond lengths are 3.13 Å. Both Eu(4)-As(6) bond lengths are 3.02 Å. There are two shorter (3.15 Å) and two longer (3.36 Å) Eu(4)-As(5) bond lengths. In the fifth Eu site, Eu(5) is bonded to one As(2), one As(4), one As(5), two equivalent As(1), and three equivalent As(3) atoms to form a mixture of distorted edge, corner, and face-sharing EuAs8 hexagonal bipyramids. The Eu(5)-As(2) bond length is 3.19 Å. The Eu(5)-As(4) bond length is 3.21 Å. The Eu(5)-As(5) bond length is 3.14 Å. There is one shorter (3.13 Å) and one longer (3.45 Å) Eu(5)-As(1) bond length. There are a spread of Eu(5)-As(3) bond distances ranging from 3.09-3.23 Å. There are six inequivalent As sites. In the first As site, As(5) is bonded in a 7-coordinate geometry to one Eu(2), one Eu(3), one Eu(5), two equivalent Eu(4), one As(5), and one As(6) atom. The As(5)-As(5) bond length is 2.53 Å. The As(5)-As(6) bond length is 2.72 Å. In the second As site, As(6) is bonded in a 7-coordinate geometry to one Eu(4), two equivalent Eu(2), two equivalent Eu(3), one As(1), and one As(5) atom. The As(6)-As(1) bond length is 2.58 Å. In the third As site, As(1) is bonded in a 8-coordinate geometry to one Eu(1), one Eu(4), two equivalent Eu(3), two equivalent Eu(5), one As(3), and one As(6) atom. The As(1)-As(3) bond length is 2.58 Å. In the fourth As site, As(2) is bonded in a 7-coordinate geometry to one Eu(1), one Eu(3), one Eu(5), three equivalent Eu(2), and one As(4) atom. The As(2)-As(4) bond length is 2.58 Å. In the fifth As site, As(3) is bonded in a 7-coordinate geometry to one Eu(2), one Eu(3), one Eu(4), three equivalent Eu(5), and one As(1) atom. In the sixth As site, As(4) is bonded in a 8-coordinate geometry to one Eu(2), one Eu(5), two equivalent Eu(1), two equivalent Eu(3), one As(2), and one As(4) atom. The As(4)-As(4) bond length is 2.61 Å.