The Family of <i>M</i><sup>II</sup><sub>3</sub>(Te<sup>IV</sup>O<sub>3</sub>)<sub>2</sub>(OH)<sub>2</sub> (<i>M</i> = Mg, Mn, Co, Ni) Compounds—Prone to Inclusion of Foreign Components into Large Hexagonal Channels
oleh: Felix Eder, Matthias Weil, Owen P. Missen, Uwe Kolitsch, Eugen Libowitzky
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2022-09-01 |
Deskripsi
<i>M</i><sup>II</sup><sub>3</sub>(Te<sup>IV</sup>O<sub>3</sub>)<sub>2</sub>(OH)<sub>2</sub> (<i>M</i> = Mg, Mn, Co, Ni) compounds crystallize isotypically in the hexagonal space group <i>P</i>6<sub>3</sub><i>mc</i> (No. 186) with unit-cell parameters of <i>a</i> ≈ 13 Å, <i>c</i> ≈ 5 Å. In the crystal structure, a framework with composition <i>M</i><sub>3</sub>(TeO<sub>3</sub>)<sub>2</sub>(OH)<sub>1.5</sub><sup>0.5+</sup> defines large hexagonal channels extending along [001] where the remaining OH<sup>−</sup> anions are located. Crystal-growth studies under mild hydrothermal conditions with subsequent structure analyses on basis of X-ray diffraction methods revealed that parts of other anions present in solution such as CO<sub>3</sub><sup>2−</sup>, SO<sub>4</sub><sup>2−</sup>, SeO<sub>4</sub><sup>2−</sup>, NO<sub>3</sub><sup>−</sup>, Cl<sup>−</sup> or Br<sup>−</sup> could partly replace the OH<sup>−</sup> anions in the channels. The incorporation of such anions into the <i>M</i><sub>3</sub>(TeO<sub>3</sub>)<sub>2</sub>(OH)<sub>2</sub> structure was confirmed by energy-dispersive X-ray spectrometry (EDS) measurements and Raman spectroscopy of selected single-crystals.