title: Multiple Ca(2+) environments in silicate glasses by high-resolution (43)Ca MQMAS NMR technique at high and ultra-high (21.8 T) magnetic fields.
abstract: We here show the (43)Ca 5QMAS NMR spectra at high field (16.4 T) and the first 7QMAS spectrum at ultra-high field (21.8 T) for geologically important Ca-containing glasses. The high-resolution MQMAS spectra present a clear evidence of multiple Ca sites in the amorphous structures that have never been identified by other analytical methods. The present study suggests that the Ca(2+) ions are mainly in 7- and 8-fold coordination sites. This will offer valuable insights for dynamic properties of magmatic liquids. The MQMAS NMR technique at high magnetic field is a unique tool to understand the detailed structural information on a specific element in solids including organic and inorganic compounds.
authors.affiliation: Advanced Technology Research Laboratories, Nippon Steel Corporation, 20-1 Shintomi, Futtsu 293-8511, Japan. kshimoda@re.nsc.co.jp
authors.forename: Keiji
authors.initials: K
authors.lastname: Shimoda
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tobu
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Shimoikeda
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nemoto
authors.forename: Koji
authors.initials: K
authors.lastname: Saito
mesh_terms: D000465:Algorithms; D002118:Calcium / Q000737:chemistry*; D004574:Electromagnetic Fields; D005898:Glass / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D012680:Sensitivity and Specificity; D017640:Silicates / Q000737:chemistry*
chemical_list: D017640:Silicates; D002118:Calcium