American Chemical Society
ic3000558_si_001.cif (443.57 kB)

Molten Salt Synthesis of a Mixed-Valent Lanthanide(III/IV) Oxychloride with an Unprecedented Sillen X24 Structure: Ce1.3Nd0.7O3Cl

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posted on 2012-04-02, 00:00 authored by Jean-François Vigier, Catherine Renard, Natacha Henry, Annabelle Laplace, Francis Abraham
A new cerium neodymium oxychloride, Ce1.3Nd0.7O3Cl, has been synthesized by precipitation in a LiCl–CaCl2 molten salt by humid argon sparging. Chemical and structure characterization have been undertaken by powder X-ray diffraction, scanning electron microscopy, high-temperature X-ray diffraction, thermogravimetric analysis, and X-ray photoelectron scattering. This oxychloride crystallizes in space group P4/nmm, a = 3.9848(3) Å and c = 12.467(2) Å, in a new Sillen-type phase represented by the symbol X24 where “quadruple” fluorite-type layers [M4O6], containing CeIV in “inner” sublayers and both CeIII and NdIII in “outer” sublayers, alternate with double-halide ion sheets. The structure is also described as a stacking of LnOCl and fluorite-type blocks and constitutes the term n = 2 of a possible series (MO2)n(NdOCl)2.