Synthesis and characterization of Mu-11: a porous sodium trisilicate Na2Si3O7 center dot H2O with 10-membered ring openings

The title compound (named Mu-11) is a new type of sodium trisilicate which was synthesized by using the quasi non-aqueous route in the presence of eth ylene glycol as solvent. This material was characterized by XRD, SEM,Si-29 solid-state MAS NMR spectroscopy, elemental and thermal analyses. The struc ture was determined by single-crystal X-ray diffraction. The symmetry is mo noclinic, space group P2(1)/c, a=7.3087(8)Angstrom, b=12.7246(13)Angstrom, c=9.0913(11)Angstrom, beta=119.01(1)degrees and V=739.39(10) Angstrom(3). T he structure consists of corrugated sheets built from four-, six- and eight -membered ring units. The connection of such sheets leads to a three-dimens ional framework with a monodimensional channel system delimited by a 10-rin g aperture. After heating to 300 degrees C another novel phase crystallizes , which is stable up to 600 degrees C. (C) 2000 Elsevier Science Ltd. All r ights reserved.