The growth habits of TiO2 and alpha-Al2O3 crystals are observed on the synt
hetic crystals in the hydrothermal or glycothermal solutions by means of TE
M and ED analysis. It is concluded that the habit of alpha-Al2O3 crystal sh
ould be the hexagonal platy {0 0 0 1} with the {1 1 (2) over bar 3} faces;
the growth habit of rutile is an elongated prism, bounded by {1 1 0}, {1 0
0} and {1 0 1} forms. These results are successfully explained by a new rul
e concerning growth habit proposed by Wen-Jun Li et al. (J. Crystal Growth,
1999, to be published). Moreover, the growth habit of rutile is related to
the concentration of precursor (TiCl4 solution). When the concentration of
TiCl4 solution increases from 0.25 to 1 mol/l, the morphology of particles
is changed from prismatic form to elongated prismatic form. Its habit chan
ge is analyzed through the study of the growth mechanism of rutile. (C) 200
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