The lanthanide oxychlorides of Ho, Er, Tm, and Yb crystallize in the hexagonal space group, R3m as a mixture of the SmSI- and YOF-type layered structures. The oxychlorides are prepared by heating Ln2O3 (Ln = Ho, Er, Tm, and Yb) with excess NH4Cl, followed by pyrohydrolysis. Crystalline phases of the lanthanide oxychlorides are obtained by heating LnOCl in LiCl/KCl fluxes at 450°C. The cell parameters obtained from X-ray powder diffraction are as follows: HoOCl, a = 3.7697 (7), c = 27.766 (6) Å; ErOCl, a = 3.745 (1), c = 27.719 (8) Å; TmOCl, a = 3.708 (2), c = 27.72 (1) Å; YbOCl, a = 3.704 (2), c = 27.68 (2) Å. A series of new pyridine intercalation compounds, (py)xLnOCl, have been prepared by reactions of pyridine with the LnOCl hosts. Intercalation compounds are characterized by X-ray powder diffraction, mass spectrometry, elemental analysis, thermal gravimetric analysis, infrared spectroscopy, and temperature-dependent magnetic susceptibility. There is no reduction of the host lattice and pyridine apparently intercalates as the neutral molecule. An acid-base interaction is proposed for the mode of intercalation of pyridine into the lanthanide oxychlorides. Further studies on the intercalation of substituted pyridines, 4-ethylpyridine, and 2,6-lutidine, indicate that the C2 axis of pyridine is oriented perpendicular to the LnOCl layers.
|Original language||English (US)|
|Number of pages||9|
|Journal||Chemistry of Materials|
|State||Published - 1994|
ASJC Scopus subject areas
- Materials Chemistry
- Materials Science(all)