LaFe5H2 crystallizes in the orthorhombic Cmmm space group. La(1) is bonded in a 4-coordinate geometry to four equivalent Fe(3), six equivalent Fe(2), and four equivalent H(1) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a linear geometry to two equivalent Fe(3), four equivalent Fe(2), and two equivalent H(1) atoms. In the second Fe site, Fe(2) is bonded in a 12-coordinate geometry to three equivalent La(1), two equivalent Fe(3), three equivalent Fe(2), and four equivalent Fe(1) atoms. In the third Fe site, Fe(3) is bonded to four equivalent La(1), four equivalent Fe(1), and four equivalent Fe(2) atoms to form distorted FeLa4Fe8 cuboctahedra that share corners with eight equivalent Fe(3)La4Fe8 cuboctahedra, corners with eight equivalent H(1)La2Fe2 tetrahedra, edges with two equivalent Fe(3)La4Fe8 cuboctahedra, edges with two equivalent H(1)La2Fe2 tetrahedra, faces with two equivalent Fe(3)La4Fe8 cuboctahedra, and faces with four equivalent H(1)La2Fe2 tetrahedra. H(1) is bonded to two equivalent La(1) and two equivalent Fe(1) atoms to form HLa2Fe2 tetrahedra that share corners with four equivalent Fe(3)La4Fe8 cuboctahedra, corners with six equivalent H(1)La2Fe2 tetrahedra,  an edgeedge with one Fe(3)La4Fe8 cuboctahedra,  an edgeedge with one H(1)La2Fe2 tetrahedra, and faces with two equivalent Fe(3)La4Fe8 cuboctahedra.
LaFe5H2 crystallizes in the orthorhombic Cmmm space group. La(1) is bonded in a 4-coordinate geometry to four equivalent Fe(3), six equivalent Fe(2), and four equivalent H(1) atoms. All La(1)-Fe(3) bond lengths are 3.31 Å. There are four shorter (2.97 Å) and two longer (3.03 Å) La(1)-Fe(2) bond lengths. All La(1)-H(1) bond lengths are 2.40 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a linear geometry to two equivalent Fe(3), four equivalent Fe(2), and two equivalent H(1) atoms. Both Fe(1)-Fe(3) bond lengths are 2.60 Å. All Fe(1)-Fe(2) bond lengths are 2.57 Å. Both Fe(1)-H(1) bond lengths are 1.66 Å. In the second Fe site, Fe(2) is bonded in a 12-coordinate geometry to three equivalent La(1), two equivalent Fe(3), three equivalent Fe(2), and four equivalent Fe(1) atoms. Both Fe(2)-Fe(3) bond lengths are 2.54 Å. There is one shorter (2.94 Å) and two longer (3.02 Å) Fe(2)-Fe(2) bond lengths. In the third Fe site, Fe(3) is bonded to four equivalent La(1), four equivalent Fe(1), and four equivalent Fe(2) atoms to form distorted FeLa4Fe8 cuboctahedra that share corners with eight equivalent Fe(3)La4Fe8 cuboctahedra, corners with eight equivalent H(1)La2Fe2 tetrahedra, edges with two equivalent Fe(3)La4Fe8 cuboctahedra, edges with two equivalent H(1)La2Fe2 tetrahedra, faces with two equivalent Fe(3)La4Fe8 cuboctahedra, and faces with four equivalent H(1)La2Fe2 tetrahedra. H(1) is bonded to two equivalent La(1) and two equivalent Fe(1) atoms to form HLa2Fe2 tetrahedra that share corners with four equivalent Fe(3)La4Fe8 cuboctahedra, corners with six equivalent H(1)La2Fe2 tetrahedra,  an edgeedge with one Fe(3)La4Fe8 cuboctahedra,  an edgeedge with one H(1)La2Fe2 tetrahedra, and faces with two equivalent Fe(3)La4Fe8 cuboctahedra.