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Amorphous Selenium Red

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Element Selenium Radiochemistry

Selenium can be prepared with either an amorphous or crystalline structure. The color of amorphous selenium is either red, in powder form, or black, in vitreous form. Crystalline monoclinic selenium is a deep red crystalline hexagonal selenium, the most stable variety, is a metallic gray.

4 Chemical And Physical Information

amorphous selenium, which exists in black and red forms. Black amorphous selenium is vitreous and is formed by the rapid cooling of liquid selenium. Red amorphous selenium is colloidal and is formed in reduction reactions (Hoffmann and King 1997). Important selenium oxidation states are -2, 0, 4, and 6.

Amorphous Selenium Flat Panel Xray Imager For

JP-5781717-B2 chemical patent summary.

Reade Advanced Materials Selenium Se Metal Selenium

Amorphous selenium is either a reddish powder or a black, vitreous solid crystalline selenium is either red or gray, depending on the crystal structure. This element resembles sulfur in its various forms and in its compounds. Selenium has many electrical properties, being both photovoltaic, where light converts to electricity, and ...

Selenium Element Uses Properties Facts Discovery

Oct 01, 2021 Amorphous selenium powder lends a red color to glasses and enamels when mixed into them. Lesson Summary Selenium (Se) is a chemical element that was discovered by Jons Jacob Berzelius in 1817.

What Are The Properties And Applicatiosn Of Seleniummis

Nov 15, 2021 The gray hexagonal crystal system is the most stable with a density of 4.81g/cm3. It also exists in three amorphous solid forms two amorphous glassy forms of selenium, red and black. The former is brittle and has a density of 4.26g/cm3. The latter density is 4.28g/cm3, the other is colloidal selenium. Selenium is brittle and toxic.

Xray Imaging Research Group Amorphous Selenium Ase

Amorphous Selenium (a-Se) Many of the detector systems being developed in our lab use a photoconductor called amorphous Selenium (a-Se) as the X-ray detector material, i.e. the material which catches the X-rays, and converts them to either charge or lower energy photons.

Selenium And Selenoproteins Its Role In Regulation Of

Mar 06, 2020 Selenium originates from Sulfide ore which partially replaces the Sulphur in certain reactions since it possesses similar physical and chemical properties of Sulphur (Meija et al. 2016). Selenium is an amorphous brick red powder and when it reaches its melting point, it tends to turn into its black vitreous form.

Optical Properties Of Selenium Researchgate

Measurements have been made of the refractive index of amorphous selenium in the red and near infra-red spectral region. The absorption coefficient of amorphous selenium has been measured in the ...

The Difference Between Amorphous Selenium And Amorphous

The amorphous selenium flat panel detector is mainly composed of an amorphous selenium layer TFT. The incident X-rays make the selenium layer generate electron-hole pairs. Under the action of an externally biased electric field, the electrons and holes move in opposite directions to form a current, and the current forms a stored charge in the ...

Electroded Avalanche Amorphous Selenium Ase

Electroded avalanche amorphous selenium (a-Se) photosensor. By lupi 210 Be the first to comment. Electroded avalanche amorphous selenium (a-Se) photosensor

1 Stephen Jasinske Selenium From Mineral

The red amorphous selenium, harvested from the scrubber system, is coked with hot water and steam to convert it to a gray crystalline form. Coked selenium is used for preparation of commercial grade selenium without further purification. Commercial selenium is produced by drying coked selenium, grinding, and sizing by screening.

Selenium Element Facts

Crystalline monoclinic selenium is a deep red color. Amorphous selenium is red in powder form and is black in vitreous form. Gray crystalline metallic selenium conducts electricity better in the light than in the dark (photoconductive) and it can convert light directly into electricity (photovoltaic).

Selenium Physical And Chemical Properties Uses

Selenium occurs in numerous allotropic forms, but is typically in an amorphous or crystalline structure. Selenium in an amorphous form is either a brick -red powder or in a black vitreous form. These arrangements of selenium do not have definite melting points.

Us3954951a Preparation Of Red Amorphous Selenium

Red amorphous selenium is obtained by precipitating selenium from a solution of selenious acid in methanol or ethanol with hydrazine or a soluble salt thereof at a temperature between about -20C....

Preparation Of Red Amorphous Selenium Xerox Corporation

Red amorphous selenium is obtained by precipitating selenium from a solution of selenious acid in methanol or ethanol with hydrazine or a soluble salt thereof at a temperature between about -20 C. and the freezing point of the solution. Furthermore, the stable red

Preparation Of Red Amorphous Selenium Xerox Corporation

A process for producing stable red amorphous selenium in particles of less than about 5 microns which comprises precipitating selenious acid with hydrazine from a solution thereof in methanol or ethanol containing not more than about 50% by weight water at a temperature between about -20C. and the freezing point of the solution and maintaining the resulting precipitate at a temperature of about -13 to

4 Chemical And Physical Information

formed by the rapid cooling of liquid selenium. Red amorphous selenium is colloidal and is formed in reduction reactions (Hoffmann and King 1997). Important selenium oxidation states are -2, 0, 4, and 6. The chemical properties of selenium are similar to sulfur. Selenium combines with metals and many nonmetals directly or in aqueous solution.

Absorption Distribution Metabolism And Excretion Of

A suspension of nanoparticles of BSA-stabilized red amorphous elemental selenium (Se) or an aqueous solution of sodium selenite was repeatedly administered by oral gavage for 28 days at 0.05 mg kg(-1) bw per day (low dose) or at 0.5 mg kg(-1) bw per day

Selenium Se Pubchem

Amorphous is either red, in powder form or black, in vitreous form. Crystalline monoclinic selenium is deep red crystalline hexagonal form, the most stable variety, is a metallic gray. Lide, D.R. CRC Handbook of Chemistry and Physics 88TH Edition 2007-2008. CRC

Digital Radiography Using Amorphous Selenium

A new amorphous selenium (a-Se) digital radiography detector is introduced. The proposed detector generates a charge image in the a-Se layer in a conventional manner, which is stored on electrode pixels at the surface of the a-Se layer. A novel method, called photoconductively activated switch (PAS)

Selenium Elemental Other Properties

CRC Press, Taylor Francis, Boca Raton, FL 2007. 4-32. Vitreous, Black selenium dark red-brown to bluish-black solid density 4.28 softens at 50 to 60 deg C and becomes elastic at 70 deg C. Red amorphous form density 4.26. When freshly precipitated, reacts with water at 50 deg C forming selenious acid and hydrogen.

Selenium Se Thermo Fisher Scientific

Selenium Ar3d 10 4s 2 4p 4. Amorphous selenium, CAS 7782-49-2, is either a reddish powder or a black, vitreous solid crystalline selenium is either red or gray, depending on the crystal structure. This element resembles sulfur in its various forms and in its compounds. Reactive Nonmetal Salts

Amorphous Selenium Nanoparticles Improve Vascular

Jun 24, 2021 Keywords amorphous selenium nanoparticles, isocarbophos, sodium hydrogen exchanger 1, apoptosis, human umbilical vein endothelial cells, vascular dysfunction Introduction Organophosphorus(OP) belongs to phosphates-containing compounds such as phosphates or thiophosphates, which is harmful to humans in two ways, acute poisoning and chronic ...

Polyamorphism Of Vapordeposited Amorphous Selenium In

Sep 29, 2020 Amorphous selenium (a-Se) has a complicated molecular structure with overcoordinated defects and dangling bonds. This light-sensitive structure can undergo significant changes including bond breakage, reconnection, and defect formation upon illumination with above-bandgap light. Light sensitivity makes a-Se a unique system to study the role of surface structure and

Reduction Of Selenite To Red Elemental Selenium By

Amongst its various forms, the red amorphous selenium is with biological activity and effects similar to those of sodium selenite but with much lower acute toxicity 15,17. It was considered the most

Doi 101002 Please Add Manuscript Number

The deposited Se film is formed as an amorphous Se phase (a-Se), with semi-transparent dark red color and bandgap of approximately 2.10 eV (Figure 1a), showing negligible photoresponse.27 To transform the amorphous film into the desired t-Se crystalline phase, it is heated to a temperature above 150C.

Selenium Drugfuture

Properties Vitreous, black selenium dark red-brown to bluish-black solid formed when molten Se is cooled rapidly. d 4.28. Softens at 50-60 and becomes elastic at 70. Red, amorphous form formed by reduction of selenious acid in water by condensation of Se vapor on a cold surface. d 4.26.

Selenium In The Environment Metabolism And

At ordinary temperature selenium is a solid substance 6. Like sulfur, selenium takes various physical forms 5,9. The amorphous seleniuma red-brick powderis obtained by precipitation from aqueous solution. For example, it is obtained by reduction of a solution of selenious acid by hydrogen, zinc or sulfur dioxide. Its density is 4.26.

Solution Growth And Characterization Of Amorphous Selenium

Jun 08, 2001 The red, amorphous selenium has a deformed chain structure, high resistivity (10 13 10 16 cm) and upon heat treatment transforms to stable hexagonal modification. In recent years, the great interest in various allotropes of selenium and their interconversion is due to its use in electronics and solid-state technology 9 , 10 , 13 ...

Preparation Of Red And Grey Elemental Selenium For Food

Apr 13, 2021 However, inorganic red amorphous selenium nanoparticles with bigger sizes (100 nm to 100 m) in aqueous and powder form were synthesised by the reaction of low and high concentrations of sodium selenite and ascorbic acid, respectively. This method is novel, simple and rapid, and suitable to prepare large quantities of nanogranules.

Optical Properties Of Selenium Iopscience

The absorption coefficient of amorphous selenium has been measured in the ultra-violet, visible and near infra-red spectral regions. The transmission coefficients of several single crystals of selenium have been measured and an estimate made of the absorption coefficient in the wavelength range 0.68 to 2.0 .

Green Synthesis And Biotransformation Of Amorphous Se

Selenium could exist in three different allotropic forms amorphous, monoclinic and trigonal phase. 13 The trigonal selenium (t-Se) phase is one of the most thermodynamically stable forms of selenium.

Identification Of The Fundamental Vibrational Modes Of

Amorphous Selenium Raman and infra-red measurements were made using cast samples of amorphous Se. TABLE 2 Symmetry assignment for the observed first order infra-red and Raman spectra of Se8 in a -monoclinic Se based on the assign- ment for the S8 in orthorhombic S clinic Se is on the basis of a comparison with the known assignment for the S ...

Selenium Se Element 34 Of Periodic Table Periodic

Nov 09, 2020 Selenium is a non metallic chemical element exists in several allotropic forms, although three are generally recognized. In chemical activity and physical properties it resembles sulfur and tellurium. It can be prepared with either an amorphous or a crystalline structure. The color of amorphous selenium is either red (in powder form) or black (in vitreous form).