Biomaterial Database

29Si MAS solid state and 129Xe NMR of porous silica. 1996

S B Oepen, and H Günther

University of Siegen, Germany.

The condensation of surface hydroxyl groups of silica after high-temperature treatment has been studied by 29Si MAS solid state and 129Xe NMR spectroscopy. Above 500 degrees C, the number of surface hydroxyl groups is diminished and intraparticle 129Xe species, which reside in the pores of silica and rapidly exchange between pores of different size, are increasingly shielded. Chemical exchange between intraparticle xenon with xenon in interparticle voids is also enhanced upon thermal treatment of silica and can be monitored by 2D EXSY spectroscopy.

UI	MeSH Term	Description	Entries
D007554	Isotopes	Atomic species differing in mass number but having the same atomic number. (Grant & Hackh's Chemical Dictionary, 5th ed)	Isotope
D009682	Magnetic Resonance Spectroscopy	Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).	In Vivo NMR Spectroscopy,MR Spectroscopy,Magnetic Resonance,NMR Spectroscopy,NMR Spectroscopy, In Vivo,Nuclear Magnetic Resonance,Spectroscopy, Magnetic Resonance,Spectroscopy, NMR,Spectroscopy, Nuclear Magnetic Resonance,Magnetic Resonance Spectroscopies,Magnetic Resonance, Nuclear,NMR Spectroscopies,Resonance Spectroscopy, Magnetic,Resonance, Magnetic,Resonance, Nuclear Magnetic,Spectroscopies, NMR,Spectroscopy, MR
D012822	Silicon Dioxide	Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid.	Silica,Aerosil,Aerosil 380,Cristobalite,Quso G-32,Quso G32,Tridymite,380, Aerosil,Dioxide, Silicon,G32, Quso,Quso G 32
D012825	Silicon	A trace element that constitutes about 27.6% of the earth's crust in the form of SILICON DIOXIDE. It does not occur free in nature. Silicon has the atomic symbol Si, atomic number 14, and atomic weight [28.084; 28.086].	Silicon-28,Silicon 28
D014979	Xenon Isotopes	Stable xenon atoms that have the same atomic number as the element xenon, but differ in atomic weight. Xe-124, 126, 128-131, 134, and 136 are stable xenon isotopes.	Isotopes, Xenon
D016062	Porosity	Condition of having pores or open spaces. This often refers to bones, bone implants, or bone cements, but can refer to the porous state of any solid substance.	Porosities