DOE OSTI2020
Sc4TaFe19P12 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are four inequivalent Sc sites. In the first Sc site, Sc is bonded in a 8-coordinate geometry to six P atoms. There are four shorter (2.74 Å) and two longer (2.81 Å) Sc–P bond lengths. In the second Sc site, Sc is bonded in a 6-coordinate geometry to six P atoms. There are a spread of Sc–P bond distances ranging from 2.71–2.84 Å. In the third Sc site, Sc is bonded in a 6-coordinate geometry to six P atoms. There are a spread of Sc–P bond distances ranging from 2.73–2.80 Å. In the fourth Sc site, Sc is bonded in a 6-coordinate geometry to six P atoms. There are a spread of Sc–P bond distances ranging from 2.70–2.76 Å. Ta is bonded in a 5-coordinate geometry to eight Fe and five P atoms. There are a spread of Ta–Fe bond distances ranging from 2.61–2.81 Å. There are a spread of Ta–P bond distances ranging from 2.49–2.61 Å. There are nineteen inequivalent Fe sites. In the first Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.18–2.33 Å. In the second Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.15–2.32 Å. In the third Fe site, Fe is bonded in a 4-coordinate geometry to two equivalent Ta and four P atoms. There are a spread of Fe–P bond distances ranging from 2.28–2.41 Å. In the fourth Fe site, Fe is bonded to four P atoms to form distorted FeP4 tetrahedra that share corners with twelve FeP4 tetrahedra and edges with three FeTaP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.15–2.31 Å. In the fifth Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.26–2.33 Å. In the sixth Fe site, Fe is bonded to one Ta and four P atoms to form distorted FeTaP4 tetrahedra that share corners with six FeP4 tetrahedra, edges with four FeP4 tetrahedra, and faces with two equivalent FeTa2P4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.24–2.28 Å. In the seventh Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.28–2.32 Å. In the eighth Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.21–2.28 Å. In the ninth Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.20–2.28 Å. In the tenth Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.19–2.27 Å. In the eleventh Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.18–2.28 Å. In the twelfth Fe site, Fe is bonded to two equivalent Ta and four P atoms to form distorted FeTa2P4 tetrahedra that share corners with eight FeP4 tetrahedra, edges with six FeTaP4 tetrahedra, and a faceface with one FeTa2P4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.26–2.36 Å. In the thirteenth Fe site, Fe is bonded in a 4-coordinate geometry to one Ta and four P atoms. There are a spread of Fe–P bond distances ranging from 2.16–2.23 Å. In the fourteenth Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.17–2.23 Å. In the fifteenth Fe site, Fe is bonded to two equivalent Ta and four P atoms to form distorted FeTa2P4 tetrahedra that share corners with six FeP4 tetrahedra, edges with two equivalent FeTa2P4 tetrahedra, and faces with three FeTa2P4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.20–2.27 Å. In the sixteenth Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are two shorter (2.18 Å) and two longer (2.23 Å) Fe–P bond lengths. In the seventeenth Fe site, Fe is bonded in a 5-coordinate geometry to five P atoms. There are a spread of Fe–P bond distances ranging from 2.28–2.54 Å. In the eighteenth 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 2.25–2.56 Å. In the nineteenth Fe site, Fe is bonded in a 5-coordinate geometry to five P atoms. There are a spread of Fe–P bond distances ranging from 2.27–2.52 Å. There are twelve inequivalent P sites. In the first P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the second P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the third P site, P is bonded in a 9-coordinate geometry to two equivalent Sc, two equivalent Ta, and five Fe atoms. In the fourth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the fifth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the sixth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the seventh P site, P is bonded in a 9-coordinate geometry to two equivalent Sc, two equivalent Ta, and five Fe atoms. In the eighth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the ninth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the tenth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc, one Ta, and six Fe atoms. In the eleventh P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the twelfth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms.