Er3O2F5: Ein Erbiumoxidfluorid mit Vernier‐Struktur |
| |
Authors: | Helge Müller‐Bunz Oliver Janka Thomas Schleid Prof. Dr. |
| |
Affiliation: | 1. Dublin, University College;2. Stuttgart, Institut für Anorganische Chemie der Universit?t;3. Stuttgart, Institut für Anorganische Chemie der Universit?tInstitut für Anorganische Chemie, Universit?t Stuttgart, Pfaffenwaldring 55, D‐70569 Stuttgart, Telefax: +49(0)711 / 685‐64241 |
| |
Abstract: | Er3O2F5: An Erbium Oxide Fluoride with Vernier‐Type Structure Attempts to synthesize multinary erbium‐trifluoride derivatives (e. g. Er3F[Si3O10], Er4F2[Si2O7][SiO4], CsEr2F7, and RbEr3F10) from mixtures of ErOF‐contaminated erbium trifluoride (ErF3) itself and appropriate other components (such as Er2O3 and SiO2 or CsF and RbF, respectively) frequently resulted in the formation of pale pink, transparent, lath‐shaped single crystals of Er3O2F5 (orthorhombic, Pnma; a = 562.48(5), b = 1710.16(14), c = 537.43(4) pm; Z = 4) as by‐product, typically after seven days at 800 °C and regardless of the applied reaction‐container material (evacuated torch‐sealed silica or silica‐jacketed arc‐welded tantalum capsules). Its crystal structure, often described as a vernier‐type arrangement consisting of two interpenetrating and almost misfitting lattices (ErOF and ErF3), contains two crystallographically different Er3+ cations in the eight‐ and seven‐plus‐one‐fold anionic coordination of bicapped trigonal prisms. Whereas (Er1)3+ carries four O2? and F? anions each, (Er2)3+ resides in the neighbourhood of only two O2?, but five plus one F? anions. As the main structural feature, however, one can consider O2?‐centred (Er3+)4 tetrahedra which share common edges to form linear double strands of the composition . Running parallel to the [100] direction and assembling like a hexagonal closest rod‐packing, their electroneutralization and three‐dimensional interconnection is achieved by three crystallographically independent F? anions (d(F??Er3+) = 221 ? 251 plus 281 pm) in three‐ and two‐plus‐two‐fold coordination of the Er3+ cations, respectively. |
| |
Keywords: | Erbium Oxides Fluorides Oxyfluorides Vernier‐Type Crystal Structures |
|
|