Abstract
The reactions of Ln2O3 (Ln = La[sbnd]Lu) with ReO2 were examined in high temperature hydrothermal water (650 °C). In all cases the rhenium oxide was added in a three-fold excess. No external mineralizer was needed and the rhenate itself acted as a sufficient mineralizer to form high quality single crystals of several crystalline products. These form in good yield with compositions varying as a function of the size of the rare earth ion. The largest sesquioxide, La2O3, forms the well-known La4Re6O19 phase, but when Ln = Nd or Pr, a new product, Ln2Re2O7(OH), is isolated. Reactions with Ln = Sm[sbnd]Tb form Ln4Re2O11, and those with Dy[sbnd]Lu form Ln2ReO5. The new Ln2Re2O7(OH) series was characterized as a new structure type by single crystal X-ray diffraction. This structure features a tetrameric Re4O16 cluster embedded in a lanthanide oxide framework. Additional detailed structural data is also provided for Tb4Re2O11 and Eu4Re2O11, which were not previously reported for the Ln4Re2O11 family. In Ln2Re2O7(OH), no direct Re[sbnd]Re bond (Re[sbnd]Re = 2.60 Å) is observed while Ln4Re2O11 appears to possess a rhenium-rhenium double bond with a Re[sbnd]Re distance of 2.42 Å. Single crystal Raman data supports both of these characterizations. Magnetic data is reported for Ln2Re2O7(OH) and Tb4Re2O11, and their behavior appears to be dominated by the f-element magnetic moments. At low temperatures Tb4Re2O11 displays possible canted antiferromagnetic coupling.
Original language | English |
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Pages (from-to) | 149-158 |
Number of pages | 10 |
Journal | Journal of Solid State Chemistry |
Volume | 275 |
DOIs | |
State | Published - Jul 2019 |
Funding
We acknowledge the DoE for support of the synthetic, structural and vibrational characterization of this work through grant DE-SC0014271 . We gratefully acknowledge Prof. Apparao M. Rao, Director of the Clemson Nanomaterials Institute, for allowing access to the Raman spectrometer and his student Anthony Childress for help in Raman measurements. Magnetic studies were supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division (MAM). We acknowledge the DoE for support of the synthetic, structural and vibrational characterization of this work through grant DE-SC0014271. We gratefully acknowledge Prof. Apparao M. Rao, Director of the Clemson Nanomaterials Institute, for allowing access to the Raman spectrometer and his student Anthony Childress for help in Raman measurements. Magnetic studies were supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division (MAM).
Keywords
- Hydrothermal
- Lanthanide
- Magnetism
- Rhenate