The hunt for LaFeSbO: Synthesis of La{sub 2}SbO{sub 2} and a case of mistaken identity

Journal Article · Sun Jan 15 00:00:00 EST 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.11.011· OSTI ID:21612865

Muir, Sean ^[1]; Vielma, Jason ^[2]; Schneider, Guenter ^[2]

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1. Department of Chemistry, Oregon State University, Corvallis, OR 97331 (United States)
2. Department of Physics, Oregon State University, Corvallis, OR 97331 (United States)

The phase La{sub 2}SbO{sub 2} has been identified and characterized in the course of our efforts to realize LaFeSbO, a composition of great interest to the superconductor community. The compound La{sub 2}SbO{sub 2} is a tetragonal layered oxypnictide containing La{sub 2}O{sub 2} layers similar to LaMPnO compositions (where M=transition metal, Pn=pnictide) separated by pnictide anion layers. In order to better understand why LaFeSbO has remained elusive, density functional theory calculations have been used to determine the ground state heats of formation for LaFeSbO, La{sub 2}SbO{sub 2}, and other competing phases within the La-Fe-Sb-O system, as well as the phonon spectrum for LaFeSbO. These efforts suggest that LaFeSbO is a potentially metastable composition. - Graphical abstract: The layered oxypnictide compounds La{sub 2}SbO{sub 2} and La{sub 1.9}Sr{sub 0.1}SbO{sub 2} have been synthesized and investigated. Both crystallize in a ThCr{sub 2}Si{sub 2} type configuration and are semiconducting. Stability of the unreported compound LaFeSbO has been investigated using density functional theory. A case of mistaken identity in the literature regarding the composition LaNiBiO is addressed. Highlights: Black-Right-Pointing-Pointer The composition La{sub 2}SbO{sub 2} has been identified. Black-Right-Pointing-Pointer La{sub 2}SbO{sub 2} belongs to an unusual group of materials containing Pn{sup 2-} anions. Black-Right-Pointing-Pointer La{sub 2}SbO{sub 2} and La{sub 1.9}Sr{sub 0.1}SbO{sub 2} are both found to be semiconducting. Black-Right-Pointing-Pointer DFT has been used to calculate heats of formation within the La-Fe-Sb-O system. Black-Right-Pointing-Pointer The phonon spectrum for LaFeSbO reveals no unstable lattice mode.

• OSTI ID: 21612865
• Journal Information: Journal of Solid State Chemistry, Vol. 185; Other Information: DOI: 10.1016/j.jssc.2011.11.011; PII: S0022-4596(11)00614-1; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

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37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANIONS
DENSITY FUNCTIONAL METHOD
FORMATION HEAT
GROUND STATES
LAYERS
MATERIALS
PHONONS
SPECTRA
STABILITY
SUPERCONDUCTORS
SYNTHESIS
TRANSITION ELEMENTS
CALCULATION METHODS
CHARGED PARTICLES
ELEMENTS
ENERGY LEVELS
ENTHALPY
IONS
METALS
PHYSICAL PROPERTIES
QUASI PARTICLES
REACTION HEAT
THERMODYNAMIC PROPERTIES
VARIATIONAL METHODS