Structure of mineral glasses--I. The feldspar glasses NaAlSi 3 O 8 , KAlSi 3 O 8 , CaAl 2 Si 2 O 8

Details Structure of mineral glasses--I. The feldspar glasses NaAlSi 3 O 8 , KAlSi 3 O 8 , CaAl 2 Si 2 O 8 Structure of mineral glasses--I. The feldspar glasses NaAlSi 3 O 8 , KAlSi 3 O 8 , CaAl 2 Si 2 O 8

Jan 1979

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1979gecoa..43...61t&link_type=abstract

Geochimica et Cosmochimica Acta, vol. 43, Issue 1, pp.61-75

Mathematics

Logic

45

Scientific paper

The short range distribution of interatomic distances in three feldspar glasses has been determined by X-ray radial distribution analysis. The resulting radial distribution functions (RDF's) are interpreted by comparison with RDF's calculated for various quasi-crystalline models of the glass structure. The experimental RDF's of the alkali feldspar glasses were found to be inconsistent with the four-membered rings of tetrahedra associated with crystalline feldspars; the structures of these glasses are probably based on interconnected six-membered rings of the type found in tridymite, nepheline, or kalsilite. In contrast, the RDF of calcic feldspar glass is consistent with a four-membered ring structure of the type found in crystalline anorthite. T-O bond lengths ( T = Si , Al ) increase from 1.60 Å in SiO 2 glass [ and (1973) Acta Cryst. A29 , 702-710] to 1.63 Å in the alkali feldspar glasses to 1.66 Å in the calcic feldspar glass due to the substitution of Al for Si in the tetrahedra] sites. The T-O-T bond angles inferred from the RDF peak positions are 151° in SiO 2 glass (see reference above), 146° in the alkali feldspar glasses, and 143° in the calcic feldspar glass. Detail in the RDF at distances greater than 5 Å suggests that the alkali feldspar glasses have a higher degree of long range order than the calcic feldspar glasses. Assuming that the structural details of our feldspar glasses are similar to those of the melts, the observed structural differences between the alkali feldspar and calcic feldspar glasses helps explain the differences in crystallization kinetics of anhydrous feldspar composition melts. Structural interpretations of some thermodynamic and rheologic phenomena associated with feldspar melts are also presented based on these results.

Affiliated with

Also associated with

No associations

Rating

Structure of mineral glasses--I. The feldspar glasses NaAlSi 3 O 8 , KAlSi 3 O 8 , CaAl 2 Si 2 O 8 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Structure of mineral glasses--I. The feldspar glasses NaAlSi 3 O 8 , KAlSi 3 O 8 , CaAl 2 Si 2 O 8, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Structure of mineral glasses--I. The feldspar glasses NaAlSi 3 O 8 , KAlSi 3 O 8 , CaAl 2 Si 2 O 8 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1142123