Covalent Stabilization of the Iridium-Containing Oxyhydrides Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>3.25</sub>H<sub>0.75</sub> and Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>2.66</sub>H<sub>1.33</sub>

Reaction between Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>4</sub> and CaH<sub>2</sub> or LiH yields the iridium-containing oxyhydride phases Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>3.25</sub>H<sub>0.75</sub> or Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>2.66</sub>H<sub>1.33</sub>, respectively. Analysis of Mn K-edge XANES data indicate the presence of Ir<sup>3+</sup> centers in these oxyhydride phases, whose low-spin d<sup>6</sup> configuration is consistent with the "covalent stabilization" of the metastable oxyhydride phases, as seen previously in analogous ruthenium and rhodium containing materials. Neutron powder diffraction data indicate the hydride ions are located exclusively within the "equatorial" anion sites of Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>3.25</sub>H<sub>0.75</sub>. In contrast, hydride ions are observed on both the equatorial and axial anion sites of Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>2.66</sub>H<sub>1.33</sub>. This highly unusual anion distribution is attributed to a combination of the strong <i>trans</i>-influence of Ir-H σ-bonds and the stabilization of <i>fac</i>-IrO<sub>3</sub>H<sub>3</sub> centers by spin-orbit coupling effects. Magnetization data indicate that Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>4</sub> and Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>3.25</sub>H<sub>0.75</sub> adopt spin glass states at low temperature, behavior which is attributable to the cation disorder in Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>4</sub> and the cation and anion disorder in Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>3.25</sub>H<sub>0.75</sub>. In contrast, magnetization data collected from Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>2.66</sub>H<sub>1.33</sub> show no evidence of any magnetic phase transition down to 5 K, consistent with the dilution of the magnetic network by the introduction of diamagnetic Ir<sup>3+</sup> on the formation of the oxyhydride phase.

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Publication Details

Journal
Inorganic Chemistry
Published
2024-11-05
DOI
https://doi.org/10.1021/acs.inorgchem.4c04057
Citations
2
Primary Topic
Magnetic and transport properties of perovskites and related materials
Type
article
Field-Weighted Citation Impact
0.24

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article

Covalent Stabilization of the Iridium-Containing Oxyhydrides Sr2Mn0.5Ir0.5O3.25H0.75 and Sr2Mn0.5Ir0.5O2.66H1.33

Michael A. Hayward, James I. Murrell
2 citations
Inorganic Chemistry
Magnetic and transport properties of perovskites and related materials
0.24
article

Covalent Stabilization of the Iridium-Containing Oxyhydrides Sr2Mn0.5Ir0.5O3.25H0.75 and Sr2Mn0.5Ir0.5O2.66H1.33

Michael A. Hayward, James I. Murrell
article en
2 citations

Abstract

Reaction between Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>4</sub> and CaH<sub>2</sub> or LiH yields the iridium-containing oxyhydride phases Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>3.25</sub>H<sub>0.75</sub> or Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>2.66</sub>H<sub>1.33</sub>, respectively. Analysis of Mn K-edge XANES data indicate the presence of Ir<sup>3+</sup> centers in these oxyhydride phases, whose low-spin d<sup>6</sup> configuration is consistent with the "covalent stabilization" of the metastable oxyhydride phases, as seen previously in analogous ruthenium and rhodium containing materials. Neutron powder diffraction data indicate the hydride ions are located exclusively within the "equatorial" anion sites of Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>3.25</sub>H<sub>0.75</sub>. In contrast, hydride ions are observed on both the equatorial and axial anion sites of Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>2.66</sub>H<sub>1.33</sub>. This highly unusual anion distribution is attributed to a combination of the strong <i>trans</i>-influence of Ir-H σ-bonds and the stabilization of <i>fac</i>-IrO<sub>3</sub>H<sub>3</sub> centers by spin-orbit coupling effects. Magnetization data indicate that Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>4</sub> and Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>3.25</sub>H<sub>0.75</sub> adopt spin glass states at low temperature, behavior which is attributable to the cation disorder in Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>4</sub> and the cation and anion disorder in Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>3.25</sub>H<sub>0.75</sub>. In contrast, magnetization data collected from Sr<sub>2</sub>Mn<sub>0.5</sub>Ir<sub>0.5</sub>O<sub>2.66</sub>H<sub>1.33</sub> show no evidence of any magnetic phase transition down to 5 K, consistent with the dilution of the magnetic network by the introduction of diamagnetic Ir<sup>3+</sup> on the formation of the oxyhydride phase.

Inorganic ChemistryVol. 63(46)
University of Oxford (GB)
Diamond Light Source, Engineering and Physical Sciences Research Council
Openalex Percentile: Top 57%
Magnetic and transport properties of perovskites and related materials
0.24
DOIOpen Access PDFOpenAlex
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