Single Crystals of Transition-metal Dioxides

Several high-temperature procedures have been described in the literature for the preparation of the transition-metal dioxides. Direct oxidation of the metals, lower oxides, chlorides, or nitrate precursors provides a convenient route to the dioxides of several metals Ti, Mn, Ru, Rh, Os, Ir, and Pt.1,3-5 (Syntheses of the rutile forms of rhodium and platinum dioxides by direct oxidation requires application of high pressures.5) Reduction of higher oxides is the most common method of synthesis for these dioxides V02, Nb02, Mo02, W02, and /3-Re02.4,6-8 Stoichiometry in these reactions is most readily controlled by use of the respective metal or a lower oxide as reductant. Chromium dioxide is normally synthesized by hydrothermal reduction of the trioxide.9 

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In spite of the fact that it is unsuitable for efficient photoelectrolysis, titanium dioxide continues to attract considerable attention as a model oxide system. Attempts to dope the oxide with transition metals have met with little success, and it is clear that care must be taken to distinguish between the introduction of localized and delocalized states (see references 99 and 100). The electrochemical properties of single-crystal rutile are still being characterized in... 

Knoop single crystal, 83 temperature effect, 78 Vickers single crystal, 93 toughness, 187 Titanium nitride (TiN), 297 hardness of thin film, 50 Titanium dioxide, TiOj, 124 Tolerance factor, 287 Topotaxy in ZrOj transformations, 272 Toughness, 145 mechanisms in Z1O2, 27 Transformation toughening, 273 Transition metal carbides, anisotropy in, 75 Transition metal nitrides, anisotropy in, 75 Trichloroborazine, 231 Tridymite, 236... 

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