EuP7 crystallizes in the monoclinic P2_1/c space group. Eu(1) is bonded in a 9-coordinate geometry to one P(1), one P(2), one P(3), one P(5), one P(7), two equivalent P(4), and two equivalent P(6) atoms. There are seven inequivalent P sites. In the first P site, P(1) is bonded to one Eu(1), one P(1), one P(3), and one P(4) atom to form PEuP3 tetrahedra that share corners with two equivalent P(6)Eu2P2 tetrahedra, corners with two equivalent P(5)EuP3 tetrahedra, corners with three equivalent P(4)Eu2P2 tetrahedra, corners with three equivalent P(7)EuP3 tetrahedra, and  a cornercorner with one P(2)EuP3 trigonal pyramid. In the second P site, P(2) is bonded to one Eu(1), one P(5), one P(6), and one P(7) atom to form distorted PEuP3 trigonal pyramids that share  a cornercorner with one P(4)Eu2P2 tetrahedra,  a cornercorner with one P(1)EuP3 tetrahedra,  a cornercorner with one P(7)EuP3 tetrahedra, corners with two equivalent P(5)EuP3 tetrahedra, corners with three equivalent P(6)Eu2P2 tetrahedra, and  an edgeedge with one P(4)Eu2P2 tetrahedra. In the third P site, P(3) is bonded in a see-saw-like geometry to one Eu(1), one P(1), one P(5), and one P(7) atom. In the fourth P site, P(4) is bonded to two equivalent Eu(1), one P(1), and one P(7) atom to form PEu2P2 tetrahedra that share corners with two equivalent P(4)Eu2P2 tetrahedra, corners with two equivalent P(5)EuP3 tetrahedra, corners with two equivalent P(7)EuP3 tetrahedra, corners with three equivalent P(1)EuP3 tetrahedra, corners with four equivalent P(6)Eu2P2 tetrahedra,  a cornercorner with one P(2)EuP3 trigonal pyramid, and  an edgeedge with one P(2)EuP3 trigonal pyramid. In the fifth P site, P(5) is bonded to one Eu(1), one P(2), one P(3), and one P(6) atom to form PEuP3 tetrahedra that share  a cornercorner with one P(6)Eu2P2 tetrahedra, corners with two equivalent P(4)Eu2P2 tetrahedra, corners with two equivalent P(1)EuP3 tetrahedra, corners with three equivalent P(7)EuP3 tetrahedra, corners with two equivalent P(2)EuP3 trigonal pyramids, and  an edgeedge with one P(6)Eu2P2 tetrahedra. In the sixth P site, P(6) is bonded to two equivalent Eu(1), one P(2), and one P(5) atom to form PEu2P2 tetrahedra that share  a cornercorner with one P(5)EuP3 tetrahedra, corners with two equivalent P(6)Eu2P2 tetrahedra, corners with two equivalent P(1)EuP3 tetrahedra, corners with three equivalent P(7)EuP3 tetrahedra, corners with four equivalent P(4)Eu2P2 tetrahedra, corners with three equivalent P(2)EuP3 trigonal pyramids, and  an edgeedge with one P(5)EuP3 tetrahedra. In the seventh P site, P(7) is bonded to one Eu(1), one P(2), one P(3), and one P(4) atom to form PEuP3 tetrahedra that share corners with two equivalent P(4)Eu2P2 tetrahedra, corners with three equivalent P(6)Eu2P2 tetrahedra, corners with three equivalent P(1)EuP3 tetrahedra, corners with three equivalent P(5)EuP3 tetrahedra, and  a cornercorner with one P(2)EuP3 trigonal pyramid.
EuP7 crystallizes in the monoclinic P2_1/c space group. Eu(1) is bonded in a 9-coordinate geometry to one P(1), one P(2), one P(3), one P(5), one P(7), two equivalent P(4), and two equivalent P(6) atoms. The Eu(1)-P(1) bond length is 3.19 Å. The Eu(1)-P(2) bond length is 3.28 Å. The Eu(1)-P(3) bond length is 3.23 Å. The Eu(1)-P(5) bond length is 3.15 Å. The Eu(1)-P(7) bond length is 3.06 Å. There is one shorter (3.10 Å) and one longer (3.12 Å) Eu(1)-P(4) bond length. There is one shorter (3.08 Å) and one longer (3.20 Å) Eu(1)-P(6) bond length. There are seven inequivalent P sites. In the first P site, P(1) is bonded to one Eu(1), one P(1), one P(3), and one P(4) atom to form PEuP3 tetrahedra that share corners with two equivalent P(6)Eu2P2 tetrahedra, corners with two equivalent P(5)EuP3 tetrahedra, corners with three equivalent P(4)Eu2P2 tetrahedra, corners with three equivalent P(7)EuP3 tetrahedra, and  a cornercorner with one P(2)EuP3 trigonal pyramid. The P(1)-P(1) bond length is 2.23 Å. The P(1)-P(3) bond length is 2.23 Å. The P(1)-P(4) bond length is 2.17 Å. In the second P site, P(2) is bonded to one Eu(1), one P(5), one P(6), and one P(7) atom to form distorted PEuP3 trigonal pyramids that share  a cornercorner with one P(4)Eu2P2 tetrahedra,  a cornercorner with one P(1)EuP3 tetrahedra,  a cornercorner with one P(7)EuP3 tetrahedra, corners with two equivalent P(5)EuP3 tetrahedra, corners with three equivalent P(6)Eu2P2 tetrahedra, and  an edgeedge with one P(4)Eu2P2 tetrahedra. The P(2)-P(5) bond length is 2.20 Å. The P(2)-P(6) bond length is 2.18 Å. The P(2)-P(7) bond length is 2.23 Å. In the third P site, P(3) is bonded in a see-saw-like geometry to one Eu(1), one P(1), one P(5), and one P(7) atom. The P(3)-P(5) bond length is 2.18 Å. The P(3)-P(7) bond length is 2.21 Å. In the fourth P site, P(4) is bonded to two equivalent Eu(1), one P(1), and one P(7) atom to form PEu2P2 tetrahedra that share corners with two equivalent P(4)Eu2P2 tetrahedra, corners with two equivalent P(5)EuP3 tetrahedra, corners with two equivalent P(7)EuP3 tetrahedra, corners with three equivalent P(1)EuP3 tetrahedra, corners with four equivalent P(6)Eu2P2 tetrahedra,  a cornercorner with one P(2)EuP3 trigonal pyramid, and  an edgeedge with one P(2)EuP3 trigonal pyramid. The P(4)-P(7) bond length is 2.20 Å. In the fifth P site, P(5) is bonded to one Eu(1), one P(2), one P(3), and one P(6) atom to form PEuP3 tetrahedra that share  a cornercorner with one P(6)Eu2P2 tetrahedra, corners with two equivalent P(4)Eu2P2 tetrahedra, corners with two equivalent P(1)EuP3 tetrahedra, corners with three equivalent P(7)EuP3 tetrahedra, corners with two equivalent P(2)EuP3 trigonal pyramids, and  an edgeedge with one P(6)Eu2P2 tetrahedra. The P(5)-P(6) bond length is 2.19 Å. In the sixth P site, P(6) is bonded to two equivalent Eu(1), one P(2), and one P(5) atom to form PEu2P2 tetrahedra that share  a cornercorner with one P(5)EuP3 tetrahedra, corners with two equivalent P(6)Eu2P2 tetrahedra, corners with two equivalent P(1)EuP3 tetrahedra, corners with three equivalent P(7)EuP3 tetrahedra, corners with four equivalent P(4)Eu2P2 tetrahedra, corners with three equivalent P(2)EuP3 trigonal pyramids, and  an edgeedge with one P(5)EuP3 tetrahedra. In the seventh P site, P(7) is bonded to one Eu(1), one P(2), one P(3), and one P(4) atom to form PEuP3 tetrahedra that share corners with two equivalent P(4)Eu2P2 tetrahedra, corners with three equivalent P(6)Eu2P2 tetrahedra, corners with three equivalent P(1)EuP3 tetrahedra, corners with three equivalent P(5)EuP3 tetrahedra, and  a cornercorner with one P(2)EuP3 trigonal pyramid.