DOE OSTI2020
Th5Fe19P12 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Th sites. In the first Th site, Th is bonded in a 6-coordinate geometry to ten Fe and six P atoms. There are a spread of Th–Fe bond distances ranging from 3.03–3.26 Å. There are two shorter (2.90 Å) and four longer (2.93 Å) Th–P bond lengths. In the second Th site, Th is bonded in a 6-coordinate geometry to ten Fe and six P atoms. There are a spread of Th–Fe bond distances ranging from 3.05–3.22 Å. There are four shorter (2.91 Å) and two longer (2.94 Å) Th–P bond lengths. In the third Th site, Th is bonded in a 8-coordinate geometry to ten Fe and six P atoms. There are a spread of Th–Fe bond distances ranging from 2.93–3.20 Å. There are a spread of Th–P bond distances ranging from 2.90–2.97 Å. There are ten inequivalent Fe sites. In the first Fe site, Fe is bonded to one Th and four P atoms to form distorted FeThP4 tetrahedra that share corners with eight FeThP4 tetrahedra, edges with four FeTh3P4 tetrahedra, and faces with two equivalent FeTh3P4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.15–2.27 Å. In the second Fe site, Fe is bonded to three equivalent Th and four P atoms to form distorted FeTh3P4 tetrahedra that share corners with eight FeThP4 tetrahedra, edges with six FeThP4 tetrahedra, and faces with four FeTh3P4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.27–2.40 Å. In the third Fe site, Fe is bonded to three Th and four P atoms to form distorted FeTh3P4 tetrahedra that share corners with seven FeThP4 tetrahedra, edges with four FeTh3P4 tetrahedra, and faces with five FeThP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.24–2.33 Å. In the fourth Fe site, Fe is bonded in a 4-coordinate geometry to three Th and four P atoms. There are a spread of Fe–P bond distances ranging from 2.26–2.37 Å. In the fifth Fe site, Fe is bonded in a 12-coordinate geometry to three Th and four P atoms. There are two shorter (2.37 Å) and two longer (2.47 Å) Fe–P bond lengths. In the sixth Fe site, Fe is bonded in a 1-coordinate geometry to five P atoms. There are a spread of Fe–P bond distances ranging from 2.25–2.57 Å. In the seventh Fe site, Fe is bonded in a 12-coordinate geometry to four equivalent Th and four P atoms. There are two shorter (2.43 Å) and two longer (2.48 Å) Fe–P bond lengths. In the eighth Fe site, Fe is bonded to three Th and four P atoms to form distorted FeTh3P4 tetrahedra that share corners with eight FeThP4 tetrahedra, edges with six FeTh3P4 tetrahedra, and faces with two FeTh3P4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.22–2.39 Å. In the ninth Fe site, Fe is bonded to four Th and four P atoms to form distorted FeTh4P4 tetrahedra that share corners with five FeThP4 tetrahedra, an edgeedge with one FeTh4P4 tetrahedra, and faces with five FeTh3P4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.33–2.44 Å. In the tenth Fe site, Fe is bonded in a 4-coordinate geometry to three Th and four P atoms. There are a spread of Fe–P bond distances ranging from 2.18–2.35 Å. There are six inequivalent P sites. In the first P site, P is bonded in a 9-coordinate geometry to four Th and five Fe atoms. In the second P site, P is bonded in a 9-coordinate geometry to two equivalent Th and seven Fe atoms. In the third P site, P is bonded in a 9-coordinate geometry to two equivalent Th and seven Fe atoms. In the fourth P site, P is bonded in a 9-coordinate geometry to three Th and six Fe atoms. In the fifth P site, P is bonded in a 9-coordinate geometry to two equivalent Th and seven Fe atoms. In the sixth P site, P is bonded in a 9-coordinate geometry to two equivalent Th and seven Fe atoms.