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Sodium Coordination Environments in Silica Films
Author(s) -
Jupille Jacques,
Flank AnneMarie,
Lagarde Pierre
Publication year - 2002
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2002.tb00220.x
Subject(s) - extended x ray absorption fine structure , sodium , ionic bonding , sodium oxide , coordination number , absorption (acoustics) , silicon , diffusion , local structure , silica glass , materials science , ionic conductivity , oxide , inorganic chemistry , oxygen , chemistry , analytical chemistry (journal) , mineralogy , ion , crystallography , absorption spectroscopy , optics , organic chemistry , thermodynamics , metallurgy , physics , composite material , electrode , electrolyte
The local structure centered on sodium after diffusion in silica (Na‐SiO 2 samples) has been determined by means of extended X‐ray absorption fine structure (EXAFS) studies. The Na‐SiO 2 samples are of particular interest because (i) their sodium content can be varied over a wide range of concentration and (ii) their local structure is representative of that of soda–silica glass. EXAFS analyses reveal the existence of a well‐defined local structure involving oxygen, sodium, and silicon neighbors. The Na‐O, Na‐Na, and Na‐Si bonds lengths, which amount to 0.23, 0.30, and 0.38 nm, respectively, do not depend on sodium concentration. This environment closely resembles that found in soda–silica glass. Moreover, it is compatible with the “target site” and “the site memory effect” suggested by recent theories of the ionic conductivity in oxide glasses.