Structure and thermal conductivity of Na{sub 1-x}Ge{sub 3+z}

Journal Article · Tue Jun 15 04:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.03.035· OSTI ID:21421511

Beekman, M; Stefanoski, S ^[1]; Wong-Ng, W ^[2]; Kaduk, J A ^[3]; Huang, Q ^[4]; Reeg, C; Bowers, C R ^[5]

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1. Department of Physics, University of South Florida, Tampa, FL 33620 (United States)
2. Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)
3. Poly Crystallography, Inc., Naperville, IL 60540 (United States)
4. NIST Center for Neutron Research, Gaithersburg, MD 20899 (United States)
5. Department of Chemistry, University of Florida, Gainesville, FL 32611 (United States)

Structural analyses as well as low temperature thermal conductivity is reported for the binary phase Na{sub 1-x}Ge{sub 3+z}. Specimens were characterized by thermal analysis, conventional and synchrotron powder X-ray diffraction, neutron powder diffraction, {sup 23}Na nuclear magnetic resonance spectroscopy, and electrical and thermal transport measurements. With structural characteristics qualitatively analogous to some aluminum-silicate zeolites, the crystal structure of this phase exhibits an unconventional covalently bonded tunnel-like Ge framework, accommodating Na in channels of two different sizes. Observed to be non-stochiometric, Na{sub 1-x}Ge{sub 3+z} concurrently exhibits substantial structural disorder in the large channels and a low lattice thermal conductivity, of interest in the context of identifying novel low thermal conductivity intermetallics for thermoelectric applications. - Graphical abstract: A zeolite-like intermetallic, Na{sub 1-x}Ge{sub 3+z}, is prepared by thermal decomposition of Na{sub 4}Ge{sub 4}. This binary phase exhibits an unusual crystal structure in which germanium forms large tunnels with significant disorder, and is found to possess a very low lattice thermal conductivity.

• OSTI ID: 21421511
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 6 Vol. 183; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALKALI METAL COMPOUNDS
ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
CHEMICAL REACTIONS
COHERENT SCATTERING
CRYSTAL STRUCTURE
DECOMPOSITION
DIFFRACTION
GERMANIUM COMPOUNDS
INORGANIC ION EXCHANGERS
INTERMETALLIC COMPOUNDS
ION EXCHANGE MATERIALS
MATERIALS
MINERALS
NEUTRON DIFFRACTION
NMR SPECTRA
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PYROLYSIS
SCATTERING
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SODIUM COMPOUNDS
SPECTRA
THERMAL ANALYSIS
THERMAL CONDUCTIVITY
THERMOCHEMICAL PROCESSES
THERMODYNAMIC PROPERTIES
X-RAY DIFFRACTION
ZEOLITES