Eu3As4 crystallizes in the monoclinic Cc space group. There are three inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to two equivalent As(1), two equivalent As(2), two equivalent As(3), and two equivalent As(4) atoms to form a mixture of corner and edge-sharing EuAs8 hexagonal bipyramids. In the second Eu site, Eu(2) is bonded in a 8-coordinate geometry to two equivalent As(1), two equivalent As(2), two equivalent As(3), and two equivalent As(4) atoms. In the third Eu site, Eu(3) is bonded in a 8-coordinate geometry to two equivalent As(1), two equivalent As(2), two equivalent As(3), and two equivalent As(4) atoms. There are four inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to two equivalent Eu(1), two equivalent Eu(2), two equivalent Eu(3), one As(3), and one As(4) atom. In the second As site, As(2) is bonded in a 7-coordinate geometry to two equivalent Eu(1), two equivalent Eu(2), two equivalent Eu(3), and one As(4) atom. In the third As site, As(3) is bonded in a 7-coordinate geometry to two equivalent Eu(1), two equivalent Eu(2), two equivalent Eu(3), and one As(1) atom. In the fourth As site, As(4) is bonded in a 8-coordinate geometry to two equivalent Eu(1), two equivalent Eu(2), two equivalent Eu(3), one As(1), and one As(2) atom.
Eu3As4 crystallizes in the monoclinic Cc space group. There are three inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to two equivalent As(1), two equivalent As(2), two equivalent As(3), and two equivalent As(4) atoms to form a mixture of corner and edge-sharing EuAs8 hexagonal bipyramids. There is one shorter (3.09 Å) and one longer (3.15 Å) Eu(1)-As(1) bond length. There is one shorter (3.08 Å) and one longer (3.13 Å) Eu(1)-As(2) bond length. There is one shorter (3.14 Å) and one longer (3.16 Å) Eu(1)-As(3) bond length. There is one shorter (3.10 Å) and one longer (3.22 Å) Eu(1)-As(4) bond length. In the second Eu site, Eu(2) is bonded in a 8-coordinate geometry to two equivalent As(1), two equivalent As(2), two equivalent As(3), and two equivalent As(4) atoms. There is one shorter (3.14 Å) and one longer (3.24 Å) Eu(2)-As(1) bond length. There is one shorter (3.15 Å) and one longer (3.16 Å) Eu(2)-As(2) bond length. There is one shorter (3.07 Å) and one longer (3.19 Å) Eu(2)-As(3) bond length. There is one shorter (3.04 Å) and one longer (3.11 Å) Eu(2)-As(4) bond length. In the third Eu site, Eu(3) is bonded in a 8-coordinate geometry to two equivalent As(1), two equivalent As(2), two equivalent As(3), and two equivalent As(4) atoms. There is one shorter (3.16 Å) and one longer (3.17 Å) Eu(3)-As(1) bond length. There is one shorter (3.09 Å) and one longer (3.15 Å) Eu(3)-As(2) bond length. There is one shorter (3.06 Å) and one longer (3.14 Å) Eu(3)-As(3) bond length. There is one shorter (3.18 Å) and one longer (3.21 Å) Eu(3)-As(4) bond length. There are four inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to two equivalent Eu(1), two equivalent Eu(2), two equivalent Eu(3), one As(3), and one As(4) atom. The As(1)-As(3) bond length is 2.47 Å. The As(1)-As(4) bond length is 2.68 Å. In the second As site, As(2) is bonded in a 7-coordinate geometry to two equivalent Eu(1), two equivalent Eu(2), two equivalent Eu(3), and one As(4) atom. The As(2)-As(4) bond length is 2.52 Å. In the third As site, As(3) is bonded in a 7-coordinate geometry to two equivalent Eu(1), two equivalent Eu(2), two equivalent Eu(3), and one As(1) atom. In the fourth As site, As(4) is bonded in a 8-coordinate geometry to two equivalent Eu(1), two equivalent Eu(2), two equivalent Eu(3), one As(1), and one As(2) atom.