There are many ways for producing phosphotungstic acid has, such as making sodium tungstate (NaWO4 • 2H2O) and phosphoric acid to react while adding hydrochloric acid during the reaction and then obtained by ether extraction.
The producing processes of phosphotungstic acid are as follows:
1. Making 1000g sodium tungstate and 16g of diammonium phosphate dissolved in boiling water 1500ml, with constant stirring, 800ml concentrated hydrochloric acid was added dropwise in it.
2.When adding half of concentrated hydrochloric acid there has some phosphotungstic acid began with isolated, wait until the solution was cooled, added without reducing agent ether about 600ml, shaking until it was divided into three layers.
3. Then through the dust-free air into ether layer, so that it can evaporation and crystallization.
4. After filter, let crystals spread evenly in the air, but never contact with dust, until they no longer have the smell of ether.

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In the tungsten dart game, the scoreboard starts as a blank sheet of paper which is usually hung on the wall about 50 cm or 1.5 feet to the left of the dartboard and at about the same height as the dartboard itself. The sequence below shows how a game is scored and how the scorecard takes form. The score shown in red is the last score thrown.

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Phosphotungstic acid catalysts are widely used in catalyst, biological staining and reagent of various alkaloids, a nitrogenous base, phenol, protein and carbohydrate and other films.
Phosphotungstic acid having acidic and redox properties, is a versatile new catalyst has high catalytic activity, while its stability is good can do homogeneous and heterogeneous reactions, even as transfer catalyst. What’s more it is kind of green and pollution-free catalyst.
In the biological sample dyeing, phosphotungstic acid used for dyeing cell samples, often used in conjunction with hematoxylin and called phosphotungstic acid-hematoxylin dye. Some three-color staining reagents will also use with phosphotungstic acid.
At the same time it as biochemical reagents and chromatography reagents mainly in separate and identification drug, chemical toxicant and toxicology analysis, forensic identification and biological material analysis. Besides it is widely used as a precipitating agent, oxidizing agent and a color agent.

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Phosphotungstic acid is a pale yellow or gray fine crystal chemical which is the heteropolyacids of H3PW12O40 and it will usually appears in hydrate. Phosphotungstic acid structure generally called Keggin structure, this ion has a complete full tetrahedral symmetry, 12 tungsten atoms and oxygen atoms connected to form a cage in the middle is a phosphorus atom. Its physical properties are as follows: chemical formula: H3O40PW12.xH2O, molecular weight: 2880.05, molar mass: 2880.2g / mol, melting point: 89 ℃, soluble in alcohol, ether and water, and no significant toxicity, but it is slightly acidic with irritants.
Phosphotungstic acid chemical properties are as follows: an aqueous solution of phosphotungstic acid is a strong oxidant and the free acid is a strong acid. It is unstable when it contact with alkali metal, most common metals, metal oxides, strong reducing agents, carbonates and cyanide exposure. Besides it cannot compatibility with ammonia, aliphatic amines, alkanolamines, aromatic amines, amino compound, an organic acid anhydride, isocyanates, alkylene oxide, and epichlorohydrin.

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In recent years, study new catalytic materials are highly valued, and many researchers have tried to develop multi-functional catalyst to replace the conventional catalysts. The study found that the supported tungsten phosphide catalyst has excellent desulfurization and denitrification activity, especially for larger molecules organic sulfides and tungsten nitride has a higher denitrification and desulfurization activity.
Tungsten phosphide catalyst producing processes are as follow:
1. Making a certain amount of (NH4) 2W4O13 • 18H2O and (NH4) 2HPO (W and P atomic ratio of 1) to react to produce phosphorus tungstate which is the precursors of tungsten phosphide.
2. Putting the amount of tungstate solution into a certain amount of r-Al2O3, after impregnation, drying and calcination to give a white WP / r-Al2O3 catalyst precursor.
3. After heating and hydrogen reduction obtain phosphide catalyst.

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Phosphorus and tungsten with different reaction condition can produce produces such as tungsten phosphide, tungsten diphosphide and so on.
Tungsten phosphide chemical formula is PW and the molecular weight is 214.8138, which is stable at room temperature and atmospheric pressure, but avoid to storage with oxide and other materials. Tungsten phosphide is general store at a closed place with room temperature, while dry and ventilated. There are some related system numbers which are as follows: CAS number: 12037-70-6, EINECS number: 234-864-7.
Tungsten phosphide produce processes are shown below:
1. Putting he amount of (NH4) 2W4O13 • 18H2O and (NH4) 2HPO in deionized water to dissolved, evaporated to dryness at 90 ℃, to obtain a viscous material.
2. Drying viscous material at 120 ℃, and then calcined at 500 ℃ for 5 hours to obtain a gray solid amorphous phosphorus tungstate.
3. Take 1.5ml phosphorus tungstate particles which are 20-40 mesh in hydrogen to heat to a certain temperature making phosphide reduction for four hours.
4. Passivation at room temperature in nitrogen stream which contain 0.5% oxygen for 12 hours.

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Nitrogen elements are widely presence in the air and the nature. And it also plays great effect in biological body, which is one of the basic elements of amino acids. Nitrogen content in the crust is small, most of the nitrogen in nature in the form of single molecules, nitrogen accounted for the volume of air about 78%. The most important mineral of nitrogen is nitrate. Tungsten and nitrogen at 2500 ℃low-pressure environment react to form tungsten dinitride.
Tungsten dinitride is a hexagonal crystal, its physical properties are as follows: chemical formula: WN2, molecular weight: 211.31, density: 7.7g•cm3, melting point: 600℃. On the other hand tungsten dinitride can decompose in water and its CAS No. is 60922-26-1.
There are two ways to produce tungsten dinitride which are shown below:
1. tungsten filament and low pressure nitrogen reacts at 2500 ℃ to obtain tungsten dinitride.
2. Using Li3N or LiNH2 as a catalyst, normal-pressure nitrogen and tungsten can be reacted at 550 ~ 600 ℃ to produce WN2.

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Tungsten nitride is a brown cubic crystal, hard texture, which β- phase and γ- phase are known. Its physical properties are as follows: chemical formula: W2N, molecular weight: 381.7, soluble in water and organic solvents. Tungsten nitride system numbers are as follows: CAS number: 12033-72-6, EINECS number: 234-792-6.
Tungsten nitride can be produced by heated tungsten in NH3, H2 and N2 atmosphere.
Tungsten nitride is a new type of catalytic materials, the surface properties and catalytic properties of it is similar to precious metals, using tungsten nitride as the catalyst can be avoided sulfur pollution which caused by using industrial catalysts, so it is as a catalyst has a broad application prospects. At the same time, tungsten nitride as a ceramic material has excellent mechanical and thermal stability. And on these two applications, nanoscale tungsten nitride is better than normal particle tungsten nitride. Nano tungsten nitride can be produced in nitrogen and hydrogen mixed atmosphere. With relevant reports, producing nano tungsten nitride can also be used pure ammonia-based method, because ammonia can break down the nitrogen and hydrogen mixed gas at elevated temperature to provide a similar atmosphere to produce tungsten nitride. Besides the ammonia production is more convenient and cheaper.

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Ditungstenpentaboride also known as tungsten boride is a black powder. Its physical properties are shown below: chemical formula: B5W2, molecular weight: 421.74, monoisotopic mass: 422.947998046875 Da. There are some related systems numbers of ditungstenpentaboride which are shown below: CAS number: 12007-98-6, EINECS number: 234-524-8, InChI: 1SV5B.2W, PubChem: 6336862. To avoid the eyes, skin and clothing in direct contact with ditungstenpentaboride, during the operations to wear the appropriate protective gear, such as gloves, goggles and masks, because careless exposure may cause skin irritation and burns. If ingested, it may cause physical harm, so to avoid inhaling ditungstenpentaboride powder, and workers need to operate at an environment where is adequate ventilated, after the end of the operation to thoroughly clean the body and mouth.

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