Rutile structure oxides

YV03 and VTa04" have been prepared from the corresponding oxides by ceramic techniques The former compound has been characterized by X-ray diffraction studies and the latter by X-ray and neutron diffraction, and magnetic measurements, which have indicated that the V and Ta " atoms are distributed statistically with respect to the Ti positions of the rutile structure. Oxidation states in the spinel FeCoV04 have been characterized by Mossbauer, magnetic, and diffraction studies Co Fe V 04 is suggested as the most probable formula. ... 

Adding Teflon emulsion, conductive polymers, carbon liber, and rutile structured oxidate to PAM as adhesives can promote the transformation of a-Pb02 into p-Pb02, enhancing electrode performance. 

The dioxides of molybdenum (violet) and tungsten (brown) are the final oxide phases produced by reduction of the trioxides with hydrogen they have rutile structures sufficiently distorted to allow the formation of M-M bonds and concomitant metallic conductivity and diamagnetism. Strong heating causes disproportionation ... 

Ruthenium and osmium have no oxides comparable to those of iron and, indeed, the lowest oxidation state in which they form oxides is -t-4. RUO2 is a blue to black solid, obtained by direct action of the elements at 1000°C, and has the rutile (p. 961) structure. The intense colour has been suggested as arising from the presence of small amounts of Ru in another oxidation state, possibly - -3. 0s02 is a yellowish-brown solid, usually prepared by heating the metal at 650°C in NO. It, too, has the rutile structure. 

For iridium the position is reversed. This time it is the black dioxide, Ir02, with the rutile structure (p. 961), which is the only definitely established oxide. It is obtained by heating the metal in oxygen or by dehydrating the precipitate produced when alkali is added to an aqueous solution of [IrCl6] . Contamination either by unreacted metal or by alkali is, however, difficult to avoid. The other oxide, Ir203, is said to be... 

Ru02 can be made by high-temperature oxidation of ruthenium. It has the rutile structure (Ru—O 1.942 A and 1.984 A) and forms blue-black crystals [49b]. 

The naturally occurring form of Sn02 (cassiterite) has the rutile structure (see Chapter 7), and it is an amphoteric oxide as illustrated by the following equations ... 

Like Sn02 Pb02 has the rutile structure, but unlike Sn02 it is a strong oxidizing agent that can be produced by the reaction... 

M-M multiple bonding has long been known in metal oxide structures. The first Mo=Mo bond was seen in one crystalline form of Mo02 which has a distorted rutile structure wherein the Mo(4+) ions occupy adjacent octahedral holes throughout the lattice ( 4). The octahedra are distorted because of the short Mo-Mo distances 2.51 X. La. RejO has a fluorite type structure in which 02 is substituted for F and four of the five Ca2 sites are occupied by La3 ions. The remaining Ca2 site is occupied by an (Re=Re)8 unit with an Re-Re distance 2.259(1) A... 

As a specific example, Li can be intercalated into several oxides with the rutile structure (Murphy, DiSalvo, Caricles and Waszczak, 1978). In Li,jMo02, the structure changes from monoclinic to octahedral and back to monoclinic as x goes from 0 to 1 (Dahn and McKinnon, 1985). In both monoclinic structures. Mo atoms are shifted to form Mo-Mo pairs along the chains (Cox, Cava, McWhan and Murphy, 1982), and these pairs disappear in the octahedral structure at intermediate x (Dahn and McKinnon, 1985). The rutile LijtW02 has been considered as a replacement for metallic Li in electrochemical cells (Murphy et al, 1978). 

Finally, a number of other mixed oxides that do not have the perovskite structure have also been examined. For example, niobium titanates with the rutile structure,tetragonal tungsten bronze... 

Anhydrous RuO has a tetragonal rutile structure with a slightly distorted octahedral structure, there being two sets of Ru-0 distances at 1.917(8) and 1.999(8) A [645] and has an extensive chemistry as a heterogeneous oxidation catalyst, a topic beyond the scope of this book. It is rarely used as a precursor for Ru oxidations, the hydrated form RuO. nH O (for brevity written below simply as RuO ) being much more effective in this respect. A procedure for converting inactive RuO (presumably the anhydrous form) to the hydrated RuO used in catalytic oxidations has been described [243]. 

The oxides in Group IV do not show an octet structure Te02 has a distorted rutile structure, in which each Te atom is surrounded by six oxygens and thus resembles the more ionic oxides Ti02 and Sn02. 

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