Structure, Chemical Bonding and 119Sn Mössbauer Spectroscopy of LaRhSn and CeRhSn

• Published in: Zeitschrift für Naturforschung. B, A journal of chemical sciences Vol. 60; no. 10; pp. 1036 - 1042
• Main Authors: Schmidt, Tobias, Johrendt, Dirk, Sebastian, C. Peter, Pöttgen, Rainer, Łątka, Kazimierz, Kmieć, Roman
• Format: Journal Article
• Language: English
• Published: Verlag der Zeitschrift für Naturforschung 02.06.2014
• Subjects: cerium; Chemical Bonding; Crystal Structure; furnaces; Intermetallics; isomers; magnetic properties; mixing; Mössbauer Spectroscopy; rhodium; spectroscopy; tantalum; tin; X-radiation
• ISSN: 0932-0776; 1865-7117
• DOI: 10.1515/znb-2005-1003

The rare earth (RE) stannides LaRhSn and CeRhSn were prepared from the elements by arcmelting or by reactions in sealed tantalum tubes in a high-frequency furnace. The structures have been refined from X-ray single crystal diffractometer data: ZrNiAl type, P6̅2̅m, a = 748.74(5), c = 422.16(3) pm, wR2 = 0.0307, 310 F values for LaRhSn and a = 745.8(1), c = 408.62(9) pm, wR2 = 0.0397, 354 F values for CeRhSn with 14 variables per refinement. The structures contain two crystallographically different rhodium sites which both have a tricapped trigonal prismatic coordination: [Rh1Sn RE ] and [Rh2Sn RE ]. Together the rhodium and tin atoms (280 - 288 pm Rh-Sn distances in LaRhSn and 277 - 285 pm in CeRhSn) build up three-dimensional [RhSn] networks in which the rare earth atoms fill distorted hexagonal channels. DFT band structure calculations reveal a large cerium 4 f contribution at the Fermi level and a strong mixing of cerium 5d/4 f with rhodium 4d orbitals. These results are in agreement with the short Ce-Rh bonds (304 and 309 pm) and also with the electronic and magnetic properties. Sn Mössbauer spectra of LaRhSn and CeRhSn show a single tin site at isomer shifts of δ = 1.98(2) (LaRhSn) and 1.79(1) mm/s (CeRhSn) subject to quadrupole splitting of Δ E = 0.79(4) (LaRhSn) and 1.12(3) mm/s (CeRhSn). The 1.8 K data show no transferred hyperfine field at the tin site for CeRhSn.