Titanium dioxide rutile and anatase

The possibility of the existence of two forms of titanium dioxide, rutile and anatase, is evident from the identity of their Coulomb energies taking the energy of the repulsive forces and of possible deformation into account, it is seen that the choice between the two structures would depend on the thermodynamic environment during crystallization. In... 

Examples of dimorphism were known in the cases of calcite and aragonite (see p. 203), the two forms of titanium dioxide (rutile and anatase), and iron disulphide in the forms of bronze-yellow pyrites and silver-white marcasite. Mitscherlich refers to groups of isomorphous elements , such as phosphorus and arsenic. He then thought ... 

Inomata, M., Mori, K., Miyamoto, A., et al. (1983). Structures of Supported Vanadium Oxide Catalysts. 1. Vanadium)V) Oxide/Titanium Dioxide (Anatase), Vanadium(V) Oxide/Titanium Dioxide (Rutile), and Vanadium(V) Oxide/Titanium Dioxide (Mixture of Anatase with Rutile), J. Phys. Chem., 87, pp. 754-761. 

Titanium dioxide exists in nature as three different polymorphs rutile, anatase and brookite. This material has been extensively studied during the last few decades due to its interesting physical properties and numerous technological applications. Rutile and anatase (a popular white pigment) are widely used in photocataly s and as sensors. Both of them have had new structural and electronic applications suggested recently (see for a review). 

The structures of rutile and anatase, the two tetragonal forms of titanium dioxide, have been determined by rigorous methods (Figs. 1 and 2). They seem at first sight to have little in common beyond the fact... 

Three forms of titanium dioxide, Ti02, are known. Of these the crystal structures of the two tetragonal forms, rutile and anatase, have been thoroughly investigated2) in each case only one parameter is involved, and the atomic arrangement has been accurately determined. The third form, brookite, is orthorhombic, with axial ratios... 

Titanium dioxide (E171, Cl white 6) is a white, opaque mineral occurring naturally in three main forms rutile, anatase, and brookite. More than 4 million tons of titanium dioxide are produced per year and it is widely used for industrial applications (paints, inks, plastics, textiles) and in small amounts as a food colorant. ° "° Production and properties — Titanium oxide is mainly produced from ilmenite, a titaniferous ore (FeTiOj). Rutile and anatase are relatively pure titanium dioxide (Ti02) forms. Titanium oxide pigment is produced via chloride or sulfate processes via the treatment of the titanium oxide ore with chlorine gas or sulfuric acid, followed by a series of purification steps. High-purity anatase is preferred for utilization in the food industry. It may be coated with small amounts of alumina or silica to improve technological properties. 

There are three crystal structures of titanium dioxide rutile, anatase, and brookite. The most active phase is rutile, which has a tetragonal structure [133], as shown in Figure 8.5 [134],... 

The most important industrial use of titanium is in the form of the dioxide (rutile or anatase) as a white pigment in the paint industry. Its outstanding property is its capacity or covering power this, with its relative chemical inertness, has resulted in its almost complete replacement of all other white pigments. Related uses arise in the paper, plastics, rubber, textile and vitreous enamel industries. 

Titanium dioxide [13463-67-7], Ti02, Mr 79.90, occurs in nature in the modifications rutile, anatase, and brookite. Rutile and anatase are produced industrially in large quantities and are used as pigments and catalysts, and in the production of ceramic and electronic materials. 

Two major processes are used for producing raw titanium dioxide pigment (1) the sulfate process, a batch process accounting for over half of current production, introduced by European makers in die early 1930s and (2) the chloride process, a continuous process, introduced in the late 1950s and accounting for most of the new plant construction since the mid-1960s. The sulfate process can handle both rutile and anatase, but the chloride process is limited to rutile. 

Titanium dioxides The most common forms of titanium dioxide (TiCL) are rutile, anatase, and brookite. Brookite is orthorhombic, whereas rutile and anatase are tetragonal (PAflmnm and lAfamd space groups, respectively) (Klein, 2002, 383-384). Titanium dioxides may sorb both As(III) and As(V) from water. The compounds are also important photocatalysts in the oxidation of As(III), MMA(V), and DMA(V) to inorganic As(V) in water (Nakajima et al., 2005 Xu, Cai and O Shea, 2007). 

Ti02 is an important oxide with a broad range of applications in catalysis (as a catalyst or a support) (6), photocatalysis (35, 36), and sensor technology it is also used as a pigment. Of the three titanium dioxide polymorphs (rutile, anatase, and brookite), rutile and anatase have been most widely investigated they are the only ones reviewed here. 

The structure of titanium complexes affects the formation of hydrated titanium dioxide structure, since rutile and anatase lattices are composed of TiO octahedrons connected in definite manner. The formation of anatase structure occurs when two octahedral complexes form a common vertex. When two octahedrons are united via their edges, rutile structure is formed. Based on this assumption, it is considered that if titanium (IV) complexes with one reactive centre are formed during hydrolysis, anatase structure is formed if there are two reactive centres, then rutile structure is formed. 

Transparent titanium dioxide exists in both rutile and anatase forms. The average primary particle size (uncoated) ranges from 8 to 25 nm. The specific surface area has values between 80 and 200 m g h Typical applications are ... 

Titanium dioxide may occur in several different crystalline forms rutile anatase and brookite. Of these, rutile and anatase are the only forms of commercial importance. Rutile is the more thermodynamically stable and is used more frequently than the other crystalline forms. 

The refractive index of a pigment at each wavelength is determined by its crystal structure. Titanium dioxide pigments (rutile and anatase) differ from each other and from other white pigments or crystalline substances, like silicon dioxide, in the proportion of radiant energy that is transmitted, absorbed, or re-... 

Titanium dioxide is known to crystallize in three polymorphic forms, anatase, brookite, and rutile. While the rutile and anatase polymorphs are commonly encountered, the brookite phase is quite rare. The... 

The monitoring of the calcination process in the production of the rutile-structured titanium dioxide from the anatase structure is recorded as a notable success [28]. A fiber optic probe appropriately positioned in the calcination kiln monitors the composition of the powder undergoing processing. The Raman bands of the two forms of titanium dioxide are quite distinct and as a result the operating conditions of the kiln (fuel and air-flows) can be adjusted to give optimum production. 

Titanium pigments n. Titanium dioxide (Ti02), rutile, and anatase, are the best examples of white pigments. 

Vauquelin investigated cerium compounds and prepared metallic cerium, tungstates, and meteorites, which Edward Howard found to consist mainly of iron and nickel. Vauquelin showed that the minerals rutile and anatase are two varieties of titanium oxide, prepared fairly pure lead dioxide by boiling red-lead with dilute nitric acid, and determined the composition of carbon disulphide by passing the vapour over red-hot copper. ... 

In Table 2.6 we give general information about three tetragonal structures two modifications (rutile and anatase) of titanium dioxide Ti02 and lanthanum cuprate La2Cu04. 

The rutile and anatase phases of titanium dioxide have been widely studied in recent years. The rutile form is used as a white pigment and opacifier, the anatase phase finds applications in photo catalysts and nanostructured solar cells. La2Cu04 has attracted considerable research efforts as it was found to become a high-Tc superconductor (Tc = 35 K) when properly doped with Sr or Ba atoms. Both Ti02 modifications contain 6 atoms (two formula units) in the primitive cell. 

---