Go toArchive
Browse byFacets
Bookbag ( 0 )
'IR spectroscopy' in keywords
Results  1 Item
Sorted by   
Publication Year
1994 (1)
1Author    J.-Ch Buhl, C. Mundus, J. Löns, W. HoffmannRequires cookie*
 Title    On the Enclathration of N aB(O H )4 in the /J-Cages of Sodalite: Crystallization Kinetics and Crystal Structure  
 Abstract    The hydrothermal formation of sodium hydroxyborate enclathrated sodalite synthesized from an initial ternary mixture of mullite, cristobalite and corundum has been investigated. Depending on temperature and pressure the compound Na7-5[AlSi04]6[B(0H)4]1.5 • 2 H 20 could be synthesized in form of polycrystalline powder as well as in form of single crystals. The kinetics of the sodalite growth could be determined at 423 K and 473 K. 29Si-and 27A1 MAS NMR was shown to be the preferred method to describe the conversion into sodalite quantitatively. Evidence for the first formation of polycrystalline sodalite has been found after the total dissolution of mullite and cristobalite. Single crystal X-ray diffraction data were used for the structure determination and refinement. The position and orientation of the hydroxyborate anions within the sodalite's /J-cages could only be found in the course of a "rigid body" refinement with constraints for the B(OH)4 tetrahedron. The boron atoms are located in an off-centre position within the sodalite cages. One out of the four oxygen atoms of the hydroxyborate group is positioned near the centre of a face of the sodium tetrahedron, whereas the three remaining oxygen atoms are near to the middle of its edges. 
  Reference    Z. Naturforsch. 49a, 1171—1178 (1994); received September 26 1994 
  Published    1994 
  Keywords    Sodalite solid solution, Crystallization kinetics, IR-spectroscopy, MAS NMR, Structure refinement 
  Similar Items    Find
 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1171.pdf 
 Identifier    ZNA-1994-49a-1171 
 Volume    49