title: 29Si and 27Al MAS NMR spectra of mullites from different kaolinites.
abstract: Mullites synthesized from four kaolinites with different random defect densities have been studied by 27Al and 29Si magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR) and X-ray diffraction (XRD). All these mullites show the same XRD pattern. However, 29Si and 27Al MAS NMR spectra reveal that the mullites derived from kaolinites with high defect densities, have a sillimanite-type Al/Si ordering scheme and are low in silica, whereas those mullites derived from kaolinites with low defect densities, consist of both sillimanite- and mullite-type Al/Si ordering schemes and are rich in silica.
authors.affiliation: Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Wushan, Guangzhou 510640, China. hehp@gig.ac.cn
authors.forename: Hongping
authors.initials: H
authors.lastname: He
authors.forename: Jiugao
authors.initials: J
authors.lastname: Guo
authors.forename: Jianxi
authors.initials: J
authors.lastname: Zhu
authors.forename: Peng
authors.initials: P
authors.lastname: Yuan
authors.forename: Cheng
authors.initials: C
authors.lastname: Hu
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D000538:Aluminum Silicates / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008968:Molecular Conformation; D012825:Silicon / Q000737:chemistry*; D013053:Spectrophotometry; D014961:X-Ray Diffraction; D017641:Zeolites / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D017641:Zeolites; C049037:aluminosilicate; D000535:Aluminum; D012825:Silicon