Rutile lattice

Germanium(IV) oxide occurs in two forms one has a rutile lattice and melts at 1359 K whilst the other has a quartz lattice and a melting point of 1389 K. It can be prepared by oxidation of germanium using, for example, concentrated nitric acid, or by the hydrolysis of germanium tetrachloride ... 

NakayamaS however, has suggested that, for rutile, which is tetragonal in structure, the strong bond between metal and oxide results from the favourable spacing between titanium ions in the rutile lattice and those in the metal structure. This explanation, however, does not account for the fact that other oxides of titanium, such as brookite, which is orthorhombic, and anatase, which is tetragonal, are also protective . 

B) The model of De Wolff disorder gives no explanation for the line broadening of reflections which are not affected by this type of lattice disorder. Chabre and Pannetier ascribed this effect to a micro twinning of the ramsdel-lite/rutile lattice on the planes [0 2 1] and [0 6 1], These faces are believed to be growth planes of EMD [45, 46],... 

Studies of the V20a-V204 system have confirmed that the phases V 02 i ( = 2—9) exist below 1400°C. ° The crystal structure of V4O7 has been shown to be based on the rutile lattice, the VOg octahedra being considerably distorted with V—O = 178—212 pm. The heat and entropy of formation of Vj Ojj at 1333 K have been determined as —373 kJmol and 146Jmol K respectively, by electrochemical measurements. ... 

Nickel and chromium mixed-phase rutile pigments are industrially important. When nickel and chromium are substituted into the rutile lattice, higher valency metals (e.g., antimony, niobium, or tungsten) must also be substituted to maintain an average valency of four. 

Therefore, the incorporation of other elements in the rutile lattice may substantially improve the performance of Vantimonate [43f]. This is also the case for Al3 +,... 

Fig. 8.7 presents our experimental results plotted by the data published in [128, 129] obtained for polycrystalline Ti02 (rutile) lattice doped with vanadium (IV) ions at different content. The linear dependence of V4+ amount (in spin/g) on total vanadium content (in at.%) shows that all vanadium ions in these samples are in (+4) state while the non-linear graph of Cioc allows to assume that some part of V4+ centers is distributed in the lattice not randomly. Such systems will be discussed in detail in section 8.5. One can see from Fig. 8.7 that Cloc and (r) values can be easily estimated by such a simple approximation as Eqs. (8.7) and (8.8). 

The same effect occurs in octahedral complexes containing Cu + (d/d ), covalency again requiring the use of 4d orbitals. CnF has a distorted rutile structure in which there are two F ions at 2.27 A and four at 1.93 A from the Cu + (Orgel and Dunitz, 1957). But when the metal ion has 5, 6, 7, 8, or 10 electrons, difluorides have essentially undistorted rutile lattices (Fig. 93). 

There are two main types of ionic oxides which are empirically formulated MOg. Where the metal ion is large (Th, 0.95 A Ce +, 0.92 A U, 0.89 A) the crystals are built up of fluorite-type unit cells with 8 4 co-ordination. But where the metal ion is smaller (Sn, 0.71 A Ti, 0.68 A) the structure is based on the rutile lattice with 6 3 co-ordination. Other examples of this structure are VOg, RuOg, PbOg and TeOg. The rutile lattice is slightly deformed in MoOg and WOg. 

The rutile lattice is adopted by Sn02 cassiterite, the most important tin-bearing mineral), Mn02 (pyrolnsite) and Pb02. 

Magnesium hydride possesses a rutile lattice, (a) Sketch a unit cell of rutile, (b) What are the coordination numbers and geometries of the Mg and H centres in this structure ... 

Figure 14.17 shows a unit cell of FeSb20g. (a) How is this unit cell related to the rutile lattice type (b) Why can the solid state structure of FeSb20g not be described in terms of a single unit cell of the rutile lattice (c) What is the coordination environment of each atom type (d) Confirm... 

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