title: [Na and Mg K-edge XANES study in silicate glasses].
abstract: The structural role of Na in Na2-O-SiO2 and Na2O-SiO2-P2O5 glasses was studied using Na K-edge XANES (X-ray near edge structure) spectra. The Na K-edge XANES shows little change with increase in the content of Na2O in Na2O-SiO2 glasses. However, the addition of P into the Na2O-SiO2 system causes dramatic change of the Na K-edge XANES, and the Na K-edge spectra of Na2O-SiO2-P2O5 glasses also change with the increase of P2O5 content. The structural role of Mg in CaMgSi2O6 (Di)--NaAlSi3O8 (Ab) glasses was studied using Mg K-edge XANES spectra. The Mg-O bond distance in these glasses is estimated to be 2.00 +/- 0.04 A. Thus, Mg in these glasses may be five coordinated with oxygen, or Mg may have multiple structural sites, MgIV, MgV and MgVI. The Di-Ab glasses may possess a medium-range ordering structure.
authors.affiliation: Institute of Gemstone and Mineral Materials, Zhongshan University, Guangzhou, 510275 China.
authors.forename: Ming-sheng
authors.initials: MS
authors.lastname: Peng
authors.forename: Di-en
authors.initials: DE
authors.lastname: Li
mesh_terms: D005898:Glass / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry; D017553:Phosphorus Compounds / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D017670:Sodium Compounds / Q000737:chemistry*; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D010087:Oxides; D017553:Phosphorus Compounds; D017680:Potassium Compounds; D017640:Silicates; D017670:Sodium Compounds; C096707:sodium oxide; C012500:phosphorus pentoxide; C068440:potassium oxide; D012822:Silicon Dioxide