RUTILE

Updated 04-May-2020.

Mondo shtuff from around the internet, all about RUTILE!

<img src='https://ui.adsabs.harvard.edu/styles/img/transparent_logo.svg' alt='Abnormal grain growth of rutile TiO₂ induced by ZrSiO₄”>Abnormal grain growth of rutile TiO₂ induced by ZrSiO₄: Abnormal grain growth (AGG) was observed in rutile TiO₂ formed by the thermal treatment of anatase TiO₂ in the presence of zirconium silicate. This morphological behaviour was seen to occur in sintered powder compacts and thin films with solid state zircon dopants and in TiO₂ coatings on grains of zircon sand. In order to clarify the mechanism of AGG in this system, various doping methods were employed and the morphological consequences of these doping methods were investigated. It was found that doping by Zr and Si does not give rise to abnormal grain growth. The observed phenomena were discussed in terms of morphological and energetic considerations. It is likely that a distinct orientation relationship between rutile TiO₂ and ZrSiO₄ and possible grain boundary liquid formation play a role in giving rise to the rapid growth of faceted prismatic rutile.

The surface science of titanium dioxide: Titanium dioxide is the most investigated single-crystalline system in the surface science of metal oxides, and the literature on rutile (1 1 0), (1 0 0), (0 0 1), and anatase surfaces is reviewed. This paper starts with a summary of the wide variety of technical fields where TiO ₂ is of importance. The bulk structure and bulk defects (as far as relevant to the surface properties) are briefly reviewed. Rules to predict stable oxide surfaces are exemplified on rutile (1 1 0). The surface structure of rutile (1 1 0) is discussed in some detail. Theoretically predicted and experimentally determined relaxations of surface geometries are compared, and defects (step edge orientations, point and line defects, impurities, surface manifestations of crystallographic shear planes—CSPs) are discussed, as well as the image contrast in scanning tunneling microscopy (STM). The controversy about the correct model for the (1×2) reconstruction appears to be settled. Different surface preparation methods, such as reoxidation of reduced crystals, can cause a drastic effect on surface geometries and morphology, and recommendations for preparing different TiO ₂(1 1 0) surfaces are given. The structure of the TiO ₂(1 0 0)-(1×1) surface is discussed and the proposed models for the (1×3) reconstruction are critically reviewed. Very recent results on anatase (1 0 0) and (1 0 1) surfaces are included. The electronic structure of stoichiometric TiO ₂ surfaces is now well understood. Surface defects can be detected with a variety of surface spectroscopies. The vibrational structure is dominated by strong Fuchs-Kliewer phonons, and high-resolution electron energy loss spectra often need to be deconvoluted in order to render useful information about adsorbed molecules. The growth of metals (Li, Na, K, Cs, Ca, Al, Ti, V, Nb, Cr, Mo, Mn, Fe, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au) as well as some metal oxides on TiO ₂ is reviewed. The tendency to ‘wet’ the overlayer, the growth morphology, the epitaxial relationship, and the strength of the interfacial oxidation/reduction reaction all follow clear trends across the periodic table, with the reactivity of the overlayer metal towards oxygen being the most decisive factor. Alkali atoms form ordered superstructures at low coverages. Recent progress in understanding the surface structure of metals in the ‘strong-metal support interaction’ (SMSI) state is summarized. Literature is reviewed on the adsorption and reaction of a wide variety of inorganic molecules (H ₂, O ₂, H ₂O, CO, CO ₂, N ₂, NH ₃, NO _x, sulfur- and halogen-containing molecules, rare gases) as well as organic molecules (carboxylic acids, alcohols, aldehydes and ketones, alkynes, pyridine and its derivates, silanes, methyl halides). The application of TiO ₂-based systems in photo-active devices is discussed, and the results on UHV-based photocatalytic studies are summarized. The review ends with a brief conclusion and outlook of TiO ₂-based surface science for the future.

<img src='https://ui.adsabs.harvard.edu/styles/img/transparent_logo.svg' alt='Ab initio study of phase stability in doped TiO₂”>Ab initio study of phase stability in doped TiO₂: Ab initio density functional theory calculations of the relative stability of the anatase and rutile polymorphs of TiO₂ were carried out using all-electron atomic orbitals methods with local density approximation. The rutile phase exhibited a moderate margin of stability of ~ 3 meV relative to the anatase phase in pristine material. From computational analysis of the formation energies of Si, Al, Fe and F dopants of various charge states across different Fermi level energies in anatase and in rutile, it was found that the cationic dopants are most stable in Ti substitutional lattice positions while formation energy is minimised for F^– doping in interstitial positions. All dopants were found to considerably stabilise anatase relative to the rutile phase, suggesting the anatase to rutile phase transformation is inhibited in such systems with the dopants ranked F > Si > Fe > Al in order of anatase stabilisation strength. Al and Fe dopants were found to act as shallow acceptors with charge compensation achieved through the formation of mobile carriers rather than the formation of anion vacancies.

My botty best at summarizing from Wikipedia: Rutile is a mineral composed primarily of titanium dioxide (TiO2), and is the most common natural form of TiO2 . Rutile has one of the highest refractive indices at visible wavelengths of thermodynamically, rutile is the most stable polymorph of TiO2 at all temperatures . it is generally the primary titanium bearing phase in most high-pressure metamorphic rocks . rutile is found as an accessory mineral in some altered igneous rocks . it is frequently seen penetrating quartz as in the fléches d’amour from Graubünden, Switzerland . in 2005 the Republic of Sierra Leone in west africa had a production capacity of 23% of the world’s annual rutile supply . the production capacity rose to approximately 30% in 2008 . Rutile crystals are most commonly the c-axis oriented growth of rutile appears clearly in nanorods, nanowires and abnormal grain growth phenomena of this phase . miners extract and separate the valuable minerals – e.g., nanoparticles of rutile are transparent to visible light but highly effective in the absorption of ultraviolet radiation . they are used in sunscreens to protect against UV-induced skin damage . small needles present in gems are star sapphires, star rubies, and other “star” gems are highly sought after . Rutile is widely used as a welding electrode covering . research efforts typically utilize small quantities of synthetic rutile . synthetic rutile is transparent and almost colorless, being slightly yellow, in large pieces . the high refractive index gives an adamantine luster and strong refraction that leads to a diamond-like appearance rutile is rarely used in jewellery because it is not very hard (scratch-resistant), measuring only about 6 on the Mohs hardness scale . the physical properties are often modified using dopants to impart improved 1920. 1920. 1930. 1920 . 1920 1920.