Zinc sulfide properties

Ethers, esters, amides and imidazolidines containing an epithio group are said to be effective in enhancing the antiwear and extreme pressure peiformance of lubricants. Other uses of thiiranes are as follows fuel gas odorant (2-methylthiirane), improvement of antistatic and wetting properties of fibers and films [poly(ethyleneglycol) ethers of 2-hydroxymethyl thiirane], inhibition of alkene metathesis (2-methylthiirane), stabilizers for poly(thiirane) (halogen adducts of thiiranes), enhancement of respiration of tobacco leaves (thiirane), tobacco additives to reduce nicotine and to reduce phenol levels in smoke [2-(methoxymethyl)thiirane], stabilizers for trichloroethylene and 1,1,1-trichloroethane (2-methylthiirane, 2-hydroxymethylthiirane) and stabilizers for organic compounds (0,0-dialkyldithiophosphate esters of 2-mercaptomethylthiirane). The product of the reaction of aniline with thiirane is reported to be useful in the flotation of zinc sulfide. 

Note Zinc sulfide (ZnS) has higher mechanical properties and better erosion resistance than zinc selenide but its optical transmission is not as good. ... 

Dhas NA, Zaban A, Gedanken A (1999) Surface synthesis of zinc sulfide nanoparticles on silica microspheres sonochemical preparation, characterization, and optical properties. Chem Mater 11(3) 806-813... 

Polycrystalline GaN UV detectors have been realized with 15% quantum efficiency [4], This is about 1 /4 of the quantum efficiency obtained by crystalline devices. Available at a fixed price, however, their increased detection range may well compensate their lack in sensitivity. Furthermore, new semiconductor materials with a matching band gap appear as promising candidates for UV detection if the presumption of the crystallinity is given up. Titanium dioxide, zinc sulfide and zinc oxide have to be mentioned. The opto-electronic properties and also low-cost production processes for these compound semiconductors have already been investigated to some extent for solar cell applications [5]. 

Table 3.4 Comparison of the properties of alkaline earth aluminate and zinc sulfide phosphorescent pigments...

White zinc sulfide pigments maintain their market position in areas of use where not only their good light scattering ability but other properties such as low abrasion, low oil number, and low Mohs hardness are required. 

Table 19. Properties of the components of zinc sulfide pigments...

Production. The raw material for the production of cadmium yellow pigments is high-purity cadmium metal (99.99 %), cadmium oxide, or cadmium carbonate. If the metal is used it is first dissolved in mineral acid. A zinc salt is then added to the solution the amount added depends on the desired shade. The zinc salt is followed by addition of sodium sulfide solution. An extremely finely divided cadmium sulfide or cadmium zinc sulfide precipitate is formed, which does not possess any pigment properties. This intermediate product can also be obtained by mixing the cadmium or cadmium-zinc salt solution with sodium carbonate solution. An alkaline cadmium carbonate or cadmium zinc carbonate precipitate is formed which reacts in suspension with added sodium sulfide solution. 

The luminescent properties can be influenced by the nature of the activators and coactivators, their concentrations, the composition of the flux, and the firing conditions. In addition, specific substitution of zinc or sulfur in the host lattice by cadmium or selenium is possible, which also influences the luminescent properties. Zinc sulfide is dimorphic and crystallizes below 1020 °C in the cubic zinc-blende structure and above that temperature in the hexagonal wurtzite lattice. When the zinc is replaced by cadmium, the transition temperature is lowered so that the hexagonal modification predominates. Substitution of sulfur by selenium, on the other hand, stabilizes the zinc-blende lattice. 

Since the first synthesis of mesoporous materials MCM-41 at Mobile Coporation,1 most work carried out in this area has focused on the preparation, characterization and applications of silica-based compounds. Recently, the synthesis of metal oxide-based mesostructured materials has attracted research attention due to their catalytic, electric, magnetic and optical properties.2 5 Although metal sulfides have found widespread applications as semiconductors, electro-optical materials and catalysts, to just name a few, only a few attempts have been reported on the synthesis of metal sulfide-based mesostructured materials. Thus far, mesostructured tin sulfides have proven to be most synthetically accessible in aqueous solution at ambient temperatures.6-7 Physical property studies showed that such materials may have potential to be used as semiconducting liquid crystals in electro-optical displays and chemical sensing applications. In addition, mesostructured thiogermanates8-10 and zinc sulfide with textured mesoporosity after surfactant removal11 have been prepared under hydrothermal conditions. 

Lithopone. Lithopone is a mixture of ZnS and BaS04. The pigmentary properties of the mixture are determined by zinc sulfide and therefore lithopone pigments are characterized by the amount of ZnS present in the mixture. The amount of ZnS in commercial lithopones varies from 15 to 60%. The most common is a 30% lithopone pigment, containing 28—30% of ZnS and 70—72% of BaS04. 

Zinc sulfide is used in applications where white color shade and low abrasivity are required In printing inks and paints it also contributes to stability and good rheological and printing properties. 

Zinc sulfide (Cleartran) 50,000-770 2.2 Reacts with strong oxidizing agents relatively inert with typical aqueous, normal acids and bases and organic solvents good thermal and mechanical shock properties low refractive index causes spectral distortions at 45° C... 

X-ray Diffraction Analysis. The inorganic components of paper are the most suitable ones for quantitative X-ray diffraction analysis. Most of these compounds are minerals and are present as fillers, coatings and pigments (often whiteners) which are added to improve the properties of the paper. Examples of compounds commonly added to paper are alumina, aluminum silicate, barium sulfate, calcium carbonate, calcium sulfate, calcium sul-foaluminate, iron oxide, magnesium silicate, silica, titanium dioxide, zinc oxide, and zinc sulfide (28). Some of these, e.g., calcium carbonate and titanium dioxide, may be present in any of... 

It should not be supposed that crystal defects enter into the picture only as nuisances which the chemist seeks to avoid or eliminate. Actually, certain optical and electrical properties of oxides, sulfides, and halides have been found to depend strongly on the nature and extent of crystal defects. Indeed, semiconductivity, fluorescence (absorption of radiation and emission of less energetic radiation), and phosphorescence (delayed fluorescence) of some salts may be spectacularly increased, not only by a small stoichiometric excess of one of the constituents, but also by addition of very tiny quantities of a foreign ion. Perhaps the best known example is the case of zinc sulfide which, when precipitated from aqueous solution and dried at low temperatures, shows negligible fluorescence upon exposure to ultraviolet light. When the sulfide is heated to... 

Zinc Sulfide and Zinc Oxides. Both materials are white but do not approach titanium dioxide for use as a tinting pigment or opacifier in plastics. Both materials can have nonpigmentary utility in plastics, such as providing whitening power at much lower abrasion levels than titanium dioxide. Zinc oxide, for instance, not only brings whitening to rubber products, but also performs as an accelerator in the vulcanization process. These products cannot compete directly with titanium dioxide when whiteness and opacity are the only criteria. However, they can play an important role when they contribute to chemical reactions and/or physical properties. 

Zinc selenide (yellow) and telluride (brown) have similar stractures to those of the sulfide, both existing in both wurtzite and zinc blende modifications. The selenide is used with zinc sulfide as a phosphor. It has the interesting property that it can act as a bine-green solid state laser bine-green laser action in solids is rare (most solid-state lasers function towards the red end, 635 nm or more, of the spectrum). At room temperature, laser action with the selenide at a wavelength of 525 nm (green) is observed and at -196°C at 495 nm (bine). Unfortunately the laser is relatively short-lived. Zinc telluride is a wide band gap semicondnctor whose electron transport properties in the form of thin films of stoichiometric and nonstoichiometric forms have been mnch studied. Its applications in optoelectronics, for example, as an optical recording material, have been reviewed. ... 

Many natural sphalerites contain substantial amounts of Fe " substituting for Zn + in the tetrahedral sites, and this system provides the opportunity to study a sulfide with increasing amounts of this transition metal. Detailed studies of the electrical and magnetic properties of iron-containing zinc sulfide by Keys et al. (1968) showed that a sphalerite with... 

Some physical and chemical properties of ZnS and BaS04 are given in Table 2.10. Tab. 2.10 Properties of the components of zinc sulfide pigments. 

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