Zinc white ZnO

The pigment zinc white (ZnO) turns bright yellow when heated, but the white color returns when the sample is cooled. Does the band gap increase or decrease when the sample is heated ... 

Zinc Oxide n (1849) (Chinese white, flowers of zinc, zinc white) ZnO. Pigment White 4 (77947) An amorphous white or yellowish powder, used as a pigment in inks, rubber, paint and plastics for mildew resistance and film reinforcing properties. It is said to have the greatest power to absorb ultraviolet light of all commercially available pigments. 

Zinc oxide is an example of zinc(Il) combining with a —2 anion. (Zn + O —> ZnO). Zinc oxide is also added to paints as a pigment and mold inhibitor and is known as zinc white when it is used as an oil paint by artists. It is used for cosmetics (ointment to protect nose and bps from ultraviolet sunlight), as a seed treatment, and as a dietary supplement. 

Several people in the 18th and 19th centuries attempted to produce a pure form of zinc oxide for medical purposes. They were unaware that their samples contained cadmium, which at that time was an unknown element. In 1817 Friedrich Strohmeyer (1776—1835), a German chemist, analyzed a zinc compound (calamine) he believed contained zinc oxide (ZnO). However, what he really found was zinc carbonate (ZnCO ), which, though at first unknown to him, contained some cadmium. Strohmeyer then treated his sample with acids until all the zinc was dissolved and thus removed. He then heated the residue with carbon black, resulting in a small ingot of soft, bluish-white metal that proved to be a new element—cadmium. Strohmeyer is given credit for the discovery of cadmium. 

Zinc oxide (ZnO) is widely used as an active filler in rubber and as a weatherability improver in polyolefins and polyesters. Titanium dioxide (TiOj) is widely used as a white pigment and as a weatherability improver in many polymers. Ground barites (BaS04) yield x-ray-opaque plastics with controlled densities. The addition of finely divided calcined alumina or silicon carbide produces abrasive composites. Zirconia, zirconium silicate, and iron oxide, which have specific gravities greater than 4.5, are used to produce plastics with controlled high densities. 

Zinc oxide [1314-33-2], ZnO, Mr 81.38, was formerly used only as a white pigment, and was named zinc white (C.I. Pigment White 4), Chinese white, or flowers of zinc. The term zinc white now denotes zinc oxide produced by the combustion of zinc metal according to the indirect or French process. 

CUT SLIVER OF ZINC. HOLD IT IN FLAME. IT BURNS WITH BLUISH-GREEN FLAME TO ZINC OXIDE. ZnO IS YELLOW WHEN HOT, WHITE WHEN COOL. 

Zinc oxide (ZnO), which is produced by burning zinc vapor in atmospheric oxygen, is by far the most important compound of zinc. Under the name of zinc white, the oxide is used as a paint pigment. It is also used as a base in the manufacture of enamels and glass, and as a ruler in the fabrication of automobile tires and other kinds of rubber goods. Zinc sulfide (ZnS) is also an important white paint pigment which is used either as such or in the form of lithopone, which is a mixture of zinc sulfide and barium sulfate. This widely used pigment is prepared by the metathetical reaction between zinc sulfate and barium sulfide, a reaction in which both of the products are insoluble ... 

Uses Zinc (Zn) is one of the most common elements in the Earth s crust. Metal zinc was first produced in India and China during the Middle Ages. Industrially important compounds of zinc are zinc chloride (ZnCl2), zinc oxide (ZnO), zinc stearate (Zn (Ci6H3502)2), and zinc sulfide (sphalerite, ZnS). It is found in air, soil, and water, and is present in all foods. Pure zinc is a bluish-white shiny metal. Zinc has many commercial uses, as coatings to prevent rust, in dry cell batteries, and mixed with other metals to make alloys like brass and bronze. Zinc combines with other elements to form zinc compounds. Zinc compounds are widely used in industry to make paint, rubber, dye, wood preservatives, and ointments.109-112... 

Zinc oxide (ZnO, wurtzite structure) eliminates oxygen on heating to form nonstoichio-metric colored phases, Zni+xO with x < 70 ppm. ZnO is almost transparent and is used as white pigment, polymer stabilizer, emollient in zinc ointments, creams and lotions, as well as in the production of Zu2Si04 for TV screens. A major application is in the rubber industry to lower the temperatures and to raise the rate of vulcanization. Furthermore, it is an n-type semiconductor (band gap 3.37 eV) and shows piezoelectric properties, making zinc oxide useful for microsensor devices and micromachined actuators. Other applications include gas sensors , solar cell windows and surface acoustic devices. ZnO has also been considered for spintronic application because of theoretical predictions of room-temperature ferromagnetism . 

Zinc Oxide (Flowers of Zinc, Zinc White, Zinc Bloom, Philosopher s Wool, Chinese White, Zincite). ZnO, mw 81.38, white or yellowish-white amorph odorless powd with a bitter taste, mp 1975° (subl and decomps), d 5.47—5.606 g/cc. V si sol in w, sol in mineral acids, dil acet acid and NH4PH. Coml prepn is from Zn or ores such as Franklinite or Zinc Blende by vapzn in a CO atm with subsequent oxidation of the vapors with preheated air. Lab, prepn is by converting anhyd zinc oxalate to ZnO by heating at... 

Other white pigments. The range of available white pigment is wide and includes white lead (basic lead carbonate, 2PbC03 Pb(OH)2) lithopone (mixed ZnS/BaS04) zinc oxide (ZnO) antimony oxide (Sb203) and titanium dioxide (Ti02). 

Zinc oxide, ZnO, is a white powder (yellow when hot) rnade by burning zinc vapor or by roasting zinc ores. It is used as a pigment (zinc white), as a filler in automobile tires, adhesive tape, and other articles, and as an antiseptic (zinc oxide ointment). 

The white paste that lifeguards rub on their nose to prevent sunburn contains zinc oxide, ZnO(5), as an active ingredient. Zinc oxide is produced by burning zinc sulfide. 

In the manufacture of zinc white by the French process, metallic zinc is melted, evaporated and oxidized in the vapor state to zinc oxide with air. If the starting material is insufficiently pure, the zinc has to be purified by evaporation and condensation prior to the oxidation step. The size and shape of the zinc oxide crystals can be controlled by the oxidation conditions. After combustion the ZnO is precipitated from the ZnO/air mixture in settling chambers, in which classification of the zinc oxide particles takes place according to their size. 

Barium and strontium sulfate are used as weighting agents in oil wells to preserve the structural integrity of the walls of a well. Barium sulfate, together with zinc sulfide (ZnS) and zinc oxide (ZnO), is a pigment for white paints. 

Zinc oxide 4117 ZnO Distilled zinc flowers of zinc peroxide of zinc red zinc ore tutty zincite zinc white. 

Zinc Oxide. Rowers of zinc philosopher s wool zinc white C.l. Pigment White 4 C.l. 77947. OZn mol wt 81.38. Zn 80.34%, O 19.66%. ZnO. Occurs as the mineral zincite. Prepd by vaporization of metallic zinc and oxidation of the vapors with preheated air (French process) also from franklinite, (American process) or from zinc sulfide Faith, Keyes Clark s Industrial Chemicals. F. A. Lowenheim. M. K. Moran, Eds. (Wiley-In terscience. New York, 4th ed 1975) pp 882-888. Purification Depew, U.S. pat. 2,372,367 (1945 to American Zinc, Lead Smelting). The medicinal grade contains 99.5% or more ZnO technical grades contain 90-99% ZnO and a few tenths of 1% of lead. See also Colour Index vol, 4 (3rd ed., 1971) p 4687. 

Zinc oxide (ZnO) occurs naturally as the mineral zincite. Chemically pure ZnO is white. Zincite is red because it contains up to 10% Mn traces of FeO are usually also present. Naturally occurring sources of zincite are not commercially important. There are two production methods for forming zinc oxide ... 

CAS 1314-13-2 EINECS/ELINCS 215-222-5 Synonyms Chinese white Cl 77947 Flowers of zinc Permanent white Philosopher s wool Pigment white 4 Zincite Zinc monoxide Zincoid Zinc white Classification Inorganic oxide Empin cal OZn Formula ZnO... 

Commercial sunscreen products are rated according to their sun protection factor (SPF), which is defined as the minimum effective dose of UV radiation that produces a delayed sunburn on protected skin compared with unprotected skin. Two types of active ingredients are found in commercial sunblocks and sunscreens.The most common sunblock agent is zinc oxide, ZnO, a white crystalline substance that reflects and scatters UV radiation. 

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