Sn-K and Pb-L[sub 3] EXAFS, X-ray diffraction, and [sup 119]Sn Moessbauer spectroscopic studies of ordered [beta]-PbSnF[sub 4] and disordered Pb[sub 1[minus]x]Sn[sub x]F[sub 2] (x = 0. 3, 0. 4) solid solutions and PbSn[sub 4]F[sub 10]: High performance fluoride ion conductors

Journal Article · Tue Jun 01 00:00:00 EDT 1993 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1993.1159· OSTI ID:5849814

Denes, G ^[1]; Yu, Y H; Tyliszczak, T; Hitchcock, A P ^[2]

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1. Concordia Univ., Montreal, Quebec (Canada)
2. McMaster Univ., Hamilton, Ontario (Canada)

Fully and partly disordered superionic conductors in the PbF[sub 2]/SnF[sub 2] system have been studied using X-ray powder diffraction, [sup 119]Sn Moessbauer spectroscopy, and Pb-L[sub 3] and Sn-K EXAFS (extended X-ray absorption fine structure). X-ray diffraction is seriously limited because of the large degree of disorder at the metal site. The solid solution Pb[sub 1[minus]x]Sn[sub x]F[sub 2] (x = 0-0.30) is fully disordered as is the stoichiometric compound PbSn[sub 4]F[sub 10] (x = 0.80). On the other hand, some degree of ordering occurs in Pb[sub 0.6]Sn[sub 0.4]F[sub 2] (x = 0.40) and [beta]-PbSnF[sub 4] (x = 0.50). [sup 119]Sn Moessbauer spectra show that the tin(II) lone pair is stereoactive in these materials. Therefore, the tin environment is highly distorted and its nonbonded electron pair is not a charge carrier in the conduction mechanism. The Sn-K and Pb-L[sub 3] EXAFS spectra indicate average first shell distances of R[sub Sn-F] = 2.12(1) [angstrom] and R[sub Pb-F] = 2.55(1) [angstrom]. There is a clear second shell Pb-Pb signal in the Pb-L[sub 3] EXAFS but no higher shell signal in the Sn-K EXAFS, indicating a higher degree of disorder and a lower rigidity of next-neighbor fluorine shells around Sn than around Pb. The results are discussed in relation to previous studies of ordered MSnF[sub 4] fluoride ionic conductors and to proposed mechanisms for ionic conduction in these superionic materials. 33 refs., 9 figs., 4 tabs.

• OSTI ID: 5849814
• Journal Information: Journal of Solid State Chemistry; (United States), Vol. 104:2; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
25 ENERGY STORAGE
LEAD FLUORIDES
CRYSTAL STRUCTURE
IONIC CONDUCTIVITY
TIN FLUORIDES
ABSORPTION SPECTROSCOPY
FINE STRUCTURE
FLUORINE IONS
MOESSBAUER EFFECT
SOLID SOLUTIONS
STEREOCHEMISTRY
STOICHIOMETRY
TIN 119
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY
CHARGED PARTICLES
COHERENT SCATTERING
DAYS LIVING RADIOISOTOPES
DIFFRACTION
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EVEN-ODD NUCLEI
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEAD COMPOUNDS
LEAD HALIDES
MIXTURES
NUCLEI
PHYSICAL PROPERTIES
RADIOISOTOPES
SCATTERING
SOLUTIONS
SPECTROSCOPY
STABLE ISOTOPES
TIN COMPOUNDS
TIN HALIDES
TIN ISOTOPES
360602* - Other Materials- Structure & Phase Studies
360606 - Other Materials- Physical Properties- (1992-)
250903 - Energy Storage- Batteries- Materials
Components
& Auxiliaries