Er3Pd7P4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 6-coordinate geometry to two equivalent Pd(1), four equivalent Pd(2), four equivalent Pd(4), two equivalent P(1), and four equivalent P(2) atoms. In the second Er site, Er(2) is bonded in a 14-coordinate geometry to two equivalent Pd(2), two equivalent Pd(3), three equivalent Pd(1), three equivalent Pd(4), two equivalent P(1), and two equivalent P(2) atoms. There are four inequivalent Pd sites. In the first Pd site, Pd(1) is bonded in a 12-coordinate geometry to one Er(1), three equivalent Er(2), one Pd(3), two equivalent Pd(1), two equivalent Pd(2), and three equivalent P(2) atoms. In the second Pd site, Pd(2) is bonded to two equivalent Er(1), two equivalent Er(2), one Pd(4), two equivalent Pd(1), two equivalent Pd(3), one P(2), and two equivalent P(1) atoms to form distorted PdEr4P3Pd5 cuboctahedra that share corners with four equivalent Pd(2)Er4P3Pd5 cuboctahedra,  an edgeedge with one Pd(2)Er4P3Pd5 cuboctahedra, faces with two equivalent Pd(3)Er4P2Pd6 cuboctahedra, and faces with three equivalent Pd(2)Er4P3Pd5 cuboctahedra. In the third Pd site, Pd(3) is bonded to four equivalent Er(2), two equivalent Pd(1), four equivalent Pd(2), and two equivalent P(1) atoms to form distorted PdEr4P2Pd6 cuboctahedra that share faces with two equivalent Pd(3)Er4P2Pd6 cuboctahedra and faces with four equivalent Pd(2)Er4P3Pd5 cuboctahedra. In the fourth Pd site, Pd(4) is bonded in a 12-coordinate geometry to two equivalent Er(1), three equivalent Er(2), one Pd(2), two equivalent Pd(4), one P(2), and three equivalent P(1) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded in a 9-coordinate geometry to one Er(1), two equivalent Er(2), one Pd(3), two equivalent Pd(2), and three equivalent Pd(4) atoms. In the second P site, P(2) is bonded in a 9-coordinate geometry to two equivalent Er(1), two equivalent Er(2), one Pd(2), one Pd(4), and three equivalent Pd(1) atoms.
Er3Pd7P4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 6-coordinate geometry to two equivalent Pd(1), four equivalent Pd(2), four equivalent Pd(4), two equivalent P(1), and four equivalent P(2) atoms. Both Er(1)-Pd(1) bond lengths are 3.21 Å. All Er(1)-Pd(2) bond lengths are 3.25 Å. All Er(1)-Pd(4) bond lengths are 3.45 Å. Both Er(1)-P(1) bond lengths are 2.94 Å. All Er(1)-P(2) bond lengths are 2.94 Å. In the second Er site, Er(2) is bonded in a 14-coordinate geometry to two equivalent Pd(2), two equivalent Pd(3), three equivalent Pd(1), three equivalent Pd(4), two equivalent P(1), and two equivalent P(2) atoms. There is one shorter (3.01 Å) and one longer (3.12 Å) Er(2)-Pd(2) bond length. Both Er(2)-Pd(3) bond lengths are 2.99 Å. There is one shorter (2.93 Å) and two longer (3.02 Å) Er(2)-Pd(1) bond lengths. There are two shorter (3.00 Å) and one longer (3.18 Å) Er(2)-Pd(4) bond length. Both Er(2)-P(1) bond lengths are 2.96 Å. Both Er(2)-P(2) bond lengths are 2.91 Å. There are four inequivalent Pd sites. In the first Pd site, Pd(1) is bonded in a 12-coordinate geometry to one Er(1), three equivalent Er(2), one Pd(3), two equivalent Pd(1), two equivalent Pd(2), and three equivalent P(2) atoms. The Pd(1)-Pd(3) bond length is 3.04 Å. Both Pd(1)-Pd(1) bond lengths are 2.84 Å. Both Pd(1)-Pd(2) bond lengths are 2.79 Å. There are two shorter (2.49 Å) and one longer (2.64 Å) Pd(1)-P(2) bond length. In the second Pd site, Pd(2) is bonded to two equivalent Er(1), two equivalent Er(2), one Pd(4), two equivalent Pd(1), two equivalent Pd(3), one P(2), and two equivalent P(1) atoms to form distorted PdEr4P3Pd5 cuboctahedra that share corners with four equivalent Pd(2)Er4P3Pd5 cuboctahedra,  an edgeedge with one Pd(2)Er4P3Pd5 cuboctahedra, faces with two equivalent Pd(3)Er4P2Pd6 cuboctahedra, and faces with three equivalent Pd(2)Er4P3Pd5 cuboctahedra. The Pd(2)-Pd(4) bond length is 2.79 Å. Both Pd(2)-Pd(3) bond lengths are 2.89 Å. The Pd(2)-P(2) bond length is 2.46 Å. Both Pd(2)-P(1) bond lengths are 2.45 Å. In the third Pd site, Pd(3) is bonded to four equivalent Er(2), two equivalent Pd(1), four equivalent Pd(2), and two equivalent P(1) atoms to form distorted PdEr4P2Pd6 cuboctahedra that share faces with two equivalent Pd(3)Er4P2Pd6 cuboctahedra and faces with four equivalent Pd(2)Er4P3Pd5 cuboctahedra. Both Pd(3)-P(1) bond lengths are 2.42 Å. In the fourth Pd site, Pd(4) is bonded in a 12-coordinate geometry to two equivalent Er(1), three equivalent Er(2), one Pd(2), two equivalent Pd(4), one P(2), and three equivalent P(1) atoms. Both Pd(4)-Pd(4) bond lengths are 2.84 Å. The Pd(4)-P(2) bond length is 2.43 Å. There is one shorter (2.48 Å) and two longer (2.57 Å) Pd(4)-P(1) bond lengths. There are two inequivalent P sites. In the first P site, P(1) is bonded in a 9-coordinate geometry to one Er(1), two equivalent Er(2), one Pd(3), two equivalent Pd(2), and three equivalent Pd(4) atoms. In the second P site, P(2) is bonded in a 9-coordinate geometry to two equivalent Er(1), two equivalent Er(2), one Pd(2), one Pd(4), and three equivalent Pd(1) atoms.