DOE OSTI2020
NaEuF4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Na–F bond distances ranging from 2.45–2.65 Å. In the second Na1+ site, Na1+ is bonded in a distorted hexagonal planar geometry to six F1- atoms. There are a spread of Na–F bond distances ranging from 2.32–2.49 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Na–F bond distances ranging from 2.32–2.61 Å. There are three inequivalent Eu3+ sites. In the first Eu3+ site, Eu3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Eu–F bond distances ranging from 2.37–2.48 Å. In the second Eu3+ site, Eu3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Eu–F bond distances ranging from 2.37–2.51 Å. In the third Eu3+ site, Eu3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Eu–F bond distances ranging from 2.40–2.45 Å. There are twelve inequivalent F1- sites. In the first F1- site, F1- is bonded to one Na1+ and three Eu3+ atoms to form a mixture of distorted corner and edge-sharing FNaEu3 tetrahedra. In the second F1- site, F1- is bonded to two Na1+ and two Eu3+ atoms to form a mixture of corner and edge-sharing FNa2Eu2 tetrahedra. In the third F1- site, F1- is bonded to two Na1+ and two Eu3+ atoms to form a mixture of distorted corner and edge-sharing FNa2Eu2 tetrahedra. In the fourth F1- site, F1- is bonded to one Na1+ and three Eu3+ atoms to form distorted FNaEu3 tetrahedra that share corners with seventeen FNaEu3 tetrahedra and edges with six FNa2Eu2 tetrahedra. In the fifth F1- site, F1- is bonded to one Na1+ and three Eu3+ atoms to form distorted FNaEu3 tetrahedra that share corners with seventeen FNaEu3 tetrahedra and edges with six FNa2Eu2 tetrahedra. In the sixth F1- site, F1- is bonded to two Na1+ and two Eu3+ atoms to form distorted FNa2Eu2 tetrahedra that share corners with seventeen FNa2Eu2 tetrahedra and edges with six FNaEu3 tetrahedra. In the seventh F1- site, F1- is bonded to two Na1+ and two Eu3+ atoms to form a mixture of distorted corner and edge-sharing FNa2Eu2 tetrahedra. In the eighth F1- site, F1- is bonded to two Na1+ and two Eu3+ atoms to form distorted FNa2Eu2 tetrahedra that share corners with seventeen FNaEu3 tetrahedra and edges with six FNa2Eu2 tetrahedra. In the ninth F1- site, F1- is bonded to two Na1+ and two Eu3+ atoms to form a mixture of distorted corner and edge-sharing FNa2Eu2 tetrahedra. In the tenth F1- site, F1- is bonded to two Na1+ and two Eu3+ atoms to form distorted FNa2Eu2 tetrahedra that share corners with seventeen FNaEu3 tetrahedra and edges with six FNa2Eu2 tetrahedra. In the eleventh F1- site, F1- is bonded to two Na1+ and two Eu3+ atoms to form a mixture of distorted corner and edge-sharing FNa2Eu2 tetrahedra. In the twelfth F1- site, F1- is bonded to two Na1+ and two Eu3+ atoms to form distorted FNa2Eu2 tetrahedra that share corners with seventeen FNa2Eu2 tetrahedra and edges with six FNaEu3 tetrahedra.