High-resolution /sup 23/Na, /sup 27/Al, and /sup 29/Si NMR spectroscopy of framework aluminosilicate glasses
The results of high-resolution /sup 23/Na, /sup 27/Al, and /sup 29/Si NMR spectroscopy of aluminosilicate glasses with MO/Al/sub 2/O/sub 3/ or L/sub 2/O/Al/sub 2/O/sub 3/ = 1 (M = +2, L = +1 cations) shows that these glasses have a fully polymerized tetrahedral framework structure with only a defect level of non-bridging oxygens. The chemical shifts of the peak maxima for all three nuclides become less shielded with decreasing Si/(Si + Al). For /sup 29/Si and /sup 27/Al, this variation parallels the variation of framework crystalline silicates. The /sup 23/Na chemical shifts for the glasses becomes less shielded (less negative) with decreasing Na/(Na + K), opposite to the trend for crystalline alkali feldspars. Few data exist for the /sup 23/Na chemical shifts of crystalline samples, and the structural causes of variation in /sup 23/Na chemical shifts are not well understood. The /sup 27/Al and /sup 29/Si chemical shifts of the glasses do not vary significantly with different large (modifier) cations. The /sup 29/Si chemical shifts provide estimates of average Si-O-T (T = Si, Al) bond angles and Si-O bond distances, and the /sup 27/Al and /sup 29/Si chemical shifts and peak breadths are consistent with a decrease in the tetrahedral ring order with decreasing Si/(Si +Al). The data presented here for fully polymerized glasses form a base from which the data for aluminosilicate glasses containing both fully polymerized sites and less polymerized sites can be interpreted.
- Research Organization:
- Univ. of Illinois, Urbana (USA)
- DOE Contract Number:
- FG02-85ER13437
- OSTI ID:
- 5062831
- Journal Information:
- Geochim. Cosmochim. Acta; (United States), Journal Name: Geochim. Cosmochim. Acta; (United States) Vol. 51:8; ISSN GCACA
- Country of Publication:
- United States
- Language:
- English
Similar Records
The structure of aluminosilicate glasses: High-resolution {sup 17}O and {sup 27}Al MAS and 3QMAS NMR study
NMR investigations of tetrapropylammonium aluminosilicate and borosilicate solutions
Related Subjects
580400* -- Geochemistry-- (-1989)
ALKALI METALS
ALUMINIUM
BOND ANGLE
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMICAL SHIFT
CHEMISTRY
ELEMENTS
GEOCHEMISTRY
GLASS
MAGNETIC RESONANCE
MATHEMATICAL MODELS
METALS
MOLECULAR MODELS
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
OXIDES
OXYGEN COMPOUNDS
POLYMERIZATION
RESONANCE
SEMIMETALS
SILICON
SILICON COMPOUNDS
SILICON OXIDES
SODIUM
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS