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Manganaro NS, Ambos SD, DeCapua M, Thiel SD, Mitchell WE, Liu Z, Zhang D, Nguyen PQH, Lavina B, Alp EE, Yan J, Walsh JPS. High-Pressure Polymorphism in Silver Ferrite Delafossite, AgFeO 2. Inorg Chem 2024; 63:9763-9770. [PMID: 38739043 DOI: 10.1021/acs.inorgchem.3c04631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
The delafossites are a class of layered metal oxides that are notable for being able to exhibit optical transparency alongside an in-plane electrical conductivity, making them promising platforms for the development of transparent conductive oxides. Pressure-induced polymorphism offers a direct method for altering the electrical and optical properties in this class, and although the copper delafossites have been studied extensively under pressure, the silver delafossites remain only partially studied. We report two new high-pressure polymorphs of silver ferrite delafossite, AgFeO2, that are stabilized above ∼6 and ∼14 GPa. In situ X-ray diffraction and vibrational spectroscopy measurements are used to examine the structural changes across the two phase transitions. The high-pressure structure between 6 and 14 GPa is assigned as a monoclinic C2/c structure that is analogous to the high-pressure phase reported for AgGaO2. Nuclear resonant forward scattering reveals no change in the spin state or valence state at the Fe3+ site up to 15.3(5) GPa.
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Affiliation(s)
- Nicholas S Manganaro
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Scott D Ambos
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Matthew DeCapua
- Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Scott D Thiel
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Wyatt E Mitchell
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Zhenxian Liu
- Department of Physics, University of Illinois Chicago, Chicago, Illinois 60607, United States
| | - Dongzhou Zhang
- GSECARS, University of Chicago, 9700 S Cass Avenue, Argonne, Lemont, Illinois 60439, United States
| | - Phuong Q H Nguyen
- GSECARS, University of Chicago, 9700 S Cass Avenue, Argonne, Lemont, Illinois 60439, United States
| | - Barbara Lavina
- GSECARS, University of Chicago, 9700 S Cass Avenue, Argonne, Lemont, Illinois 60439, United States
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
| | - Esen Ercan Alp
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
| | - Jun Yan
- Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - James P S Walsh
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
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Synthesis, Characterization, and Crystal Structure Determination of a New Lithium Zinc Iodate Polymorph LiZn(IO3)3. CRYSTALS 2019. [DOI: 10.3390/cryst9090464] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Synthesis and characterization of anhydrous LiZn(IO3)3 powders prepared from an aqueous solution are reported. Morphological and compositional analyses were carried out by using scanning electron microscopy and energy-dispersive X-ray measurements. The synthesized powders exhibited a needle-like morphology after annealing at 400 °C. A crystal structure for the synthesized compound was proposed from powder X-ray diffraction and density-functional theory calculations. Rietveld refinements led to a monoclinic structure, which can be described with space group P21, number 4, and unit-cell parameters a = 21.874(9) Å, b = 5.171(2) Å, c = 5.433(2) Å, and = 120.93(4)°. Density-functional theory calculations supported the same crystal structure. Infrared spectra were also collected, and the vibrations associated with the different modes were discussed. The non-centrosymmetric space group determined for this new polymorph of LiZn(IO3)3, the characteristics of its infrared absorption spectrum, and the observed second-harmonic generation suggest it is a promising infrared non-linear optical material.
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Molecularly Engineered Lithium–Chromium Alkoxide for Selective Synthesis of LiCrO2 and Li2CrO4 Nanomaterials. INORGANICS 2019. [DOI: 10.3390/inorganics7020022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Achieving control over the phase-selective synthesis of mixed metal oxide materials remains a challenge to the synthetic chemist due to diffusion-driven growth, which necessitates the search for new compounds with pre-existent chemical bonds between the phase-forming elements. We report here a simple solvothermal process to fabricate LiCrO2 and Li2CrO4 nanoparticles from bimetallic single-source precursors, demonstrating the distinctive influence of molecular design and calcination conditions on the resulting nanomaterials. The chemical identity of [Li2Cr(OtBu)4Cl(THF)2] (1) and [LiCr(OtBu)2(PyCH=COCF3)2(THF)2] (2) was unambiguously established in the solid state by single-crystal X-ray diffraction, revealing the formation of a coordination polymeric chain in compound 1, whereas electron paramagnetic resonance spectroscopy (EPR) studies revealed a monomeric structure in solution. TEM analysis of synthesized LiCrO2 nanoparticles showed nearly uniform particles size of approximately 20 nm. The sensitivity of the LiCrO2 phase towards oxidation was investigated by X-ray diffraction, revealing the formation of the stable Li2CrO4 after calcination in air.
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