Class B Sodalites: Nonstoichiometric Silver, Sodium Halosodalites
Abstract
Nonstoichiometric silver, sodium bromosodalites of the compositions M8-2nN2nX2-pOHp-SOD and M8-p-2nN2nX2-pp-SOD have been synthesized, where M, N = Ag+, Na+; X = Cl-; Br, I-; 2n = 0-8; p = 0-2; refers to anion-free cages and SOD = (SiAI04)66-. These materials allow one to control the filling of both Ag+ and X-ions in a sodalite host lattice in a systematic manner, to fabricate Na4-nAgnX semiconductor-component clusters. Combined results from powder XRD, Rietveld refinement, 23Na MAS and DOR NMR, far-IR and mid-IR indicate that these sodalites form a solid solution of Na3-mAgm clusters in anion-free Beta-cages interspersed with Na4nAgnX. The clusters are statistically distributed throughout the lattice. However, silver ions are associated preferentially with cavities containing halide anions. The data also demonstrate that these materials offer the opportunity to manipulate the extent of collective electronic and vibrational interactions between monodispersed Na4,AgnBr clusters in a perfectly crystalline host. 'Me anion strongly mediates the vibrational coupling. The electronic coupling between clusters increases with Ag+ and X-loading level. Support for this idea comes from extended Huckel molecular orbital calculations. At low Ag+/X-loadings, intrasodalite AgX resembles the gas phase molecule (bond length, optical spectra). Optical absorption bands broaden and the absorption edge moves towards that of the bulk semiconductor at higher Ag+/X-loadings.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 15, 1992
- Accession Number
- ADA251187
Entities
People
- A. Stein
- G. A. Ozin
- Galen D. Stucky
Organizations
- University of California, Santa Barbara