Crystallization of forsterite xerogel under carbon dioxide: A new crystalline material synthesized by homogeneous distribution of carbonaceous component into forsterite xerogel
My. Song et al., Crystallization of forsterite xerogel under carbon dioxide: A new crystalline material synthesized by homogeneous distribution of carbonaceous component into forsterite xerogel, B KOR CHEM, 20(5), 1999, pp. 517-524
By heating the magnesiumsilicate (Mg2SiO4: forsterite) xerogel in carbon di
oxide, carbonaceous component was intentionally introduced into the amorpho
us solid precursor. Carbon was introduced homogeneously as unidentate carbo
nate. Upon being heated at 800 degrees C in carbon dioxide, the xerogel whi
ch had homogeneously distributed carbonaceous component in it crystallized
into a single phase product of a new crystalline material, which had approx
imate composition of Mg8Si4O18C The powder X-ray diffraction pattern of the
new crystalline material did not match with any known crystalline compound
registered in the powder diffraction file. Crystallization from amorphous
xerogel to the new crystalline phase occurred in a very narrow range of tem
perature, from 750 degrees C to 850 degrees C in carbon dioxide, or in dry
oxygen. Upon being heated above 850 degrees C, carbonaceous component was e
xpelled from the product, accompanied by irreversible transition from the n
ew crystalline material to forsterite.