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

Journal Article · Sun Jan 15 04:00:00 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]

---

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, Journal Name: Journal of Solid State Chemistry Vol. 185; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

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