Synthesis and spectroscopic characterization of P-doped Na{sub 4}Si{sub 4}

Journal Article · Mon Nov 15 04:00:00 EST 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.07.051· OSTI ID:21494106

Jialing, Wang ^[1]; Sen, Sabyasachi ^[2]; Ping, Yu ^[3]; Browning, Nigel D ^[2]

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1. Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616 (United States)
2. Department of Chemical Engineering and Materials Science, University of California, One Shields Avenue, Davis, CA 95616 (United States)
3. NMR Facility, University of California, One Shields Avenue, Davis, CA 95616 (United States)

Na{sub 4}Si{sub 4} is a Zintl salt composed of Na{sup +} cations and Si{sub 4}{sup 4-} tetrahedral anions and is a unique solid-state precursor to clathrate structures and nanomaterials. In order to provide opportunities for the synthesis of complex materials, phosphorus was explored as a possible substituent for silicon. Phosphorus doped sodium silicides Na{sub 4}Si{sub 4-x}P{sub x} (x{<=}0.04) were prepared by reaction of Na with the mechanically alloyed Si{sub 4-x}:P{sub x} (x=0.04, 0.08, 0.12) mixture in a sealed Nb tube at 650 {sup o}C for 3 days. Energy dispersive X-ray spectroscopy confirms the presence of P in all products. Powder X-ray diffraction patterns are consistent with the retention of the Na{sub 4}Si{sub 4} crystal structure. As the amount of P increases, a new peak in the diffraction pattern that can be assigned to black phosphorus is apparent above the background. Raman and solid-state NMR provide information on phosphorus substitution in the Na{sub 4}Si{sub 4} structure. Raman spectroscopy shows a shift of the most intense band assigned to the Si{sub 4}{sup 4-} {nu}{sub 1} (A{sub 1}) mode from 486.4 to 484.0 cm{sup -1} with increasing P, consistent with P replacement of Si. Differential nuclear spin-lattice relaxation for the Si sites determined via {sup 29}Si solid-state NMR provides direct evidence for Si-P bonding in the (Si{sub 1-x}P{sub x}){sup 4-} tetrahedron. The {sup 23}Na NMR shows additional Na...P interactions and the {sup 31}P NMR shows two P sites, consistent with P presence in both of the crystallographic sites in the (Si{sub 4}){sup 4-} tetrahedron. - Graphical abstract: P-doped Na{sub 4}Si{sub 4} has been prepared and Raman spectroscopy and {sup 29}Si, {sup 23}Na, and {sup 31}P multinuclear NMR show that P dopes into both crystallographic sites for Si. Display Omitted

• OSTI ID: 21494106
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 11 Vol. 183; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ALKALI METAL COMPOUNDS
ANIONS
CATIONS
CHARGED PARTICLES
CLATHRATES
COHERENT SCATTERING
CRYSTAL STRUCTURE
CRYSTALLOGRAPHY
DIFFRACTION
DOPED MATERIALS
ELEMENTS
IONS
LASER SPECTROSCOPY
MAGNETIC RESONANCE
MATERIALS
NANOSTRUCTURES
NONMETALS
NUCLEAR MAGNETIC RESONANCE
PHOSPHORUS
RAMAN SPECTROSCOPY
RELAXATION
RESONANCE
SCATTERING
SEMIMETALS
SILICIDES
SILICON
SILICON COMPOUNDS
SODIUM COMPOUNDS
SODIUM IONS
SODIUM SILICIDES
SPECTROSCOPY
SPIN-LATTICE RELAXATION
SYNTHESIS
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY