Mercury arsenides

Mercury Arsenides.—Arsenic does not dissolve in mercury even at the boiling point,2 nor has an amalgam been obtained by the action of sodium amalgam on moist arsenious oxide 3 or by electrolysis of a solution of arsenic trichloride using a mercury cathode 4 in the latter case arsenic is deposited on the surface of the mercury but does not dissolve. Nevertheless, two arsenides of mercury, which appear to be definite compounds, have been prepared. 

Mercury-chloride impregnated As 300 ppt Mercury arsenide deposit [26]... 

As mentioned in Chapter II, many metallic arsenides are found in Nature. Arsenic combines directly with most metals to form stable compounds, those of the heavy metals being the most stable. The latter may be obtained by allowing an aqueous solution of a salt of the appropriate metal to drop into an atmosphere of arsine, air being completely absent, and the vessel continually shaken.1 Precipitation by passing arsine into the salt solution is not satisfactory as, in the case of copper, silver, gold, mercury and lead, a secondary reaction with the excess of metallic ions occurs ... 

Mercuric arsenide forms microscopic mamellated crystals. When dry it oxidises readily in the air to arsenious oxide and mercury. On heating it volatilises without melting, forming a sublimate of arsenic and mercury and a little arsenious oxide. The arsenide is therefore dried under diminished pressure. When heated with an alkyl iodide, a diarsonium mercuriodide of the type As2R6I2.2HgI2 is formed.8... 

Mercurous Arsenide, Hg3As, was obtained by Brukl9 as a black precipitate by dropping an aqueous solution of a mercurous salt into an atmosphere of arsine in complete absence of air. It is readily oxidised, and on keeping in air it yields mercury and arsenious oxide. It dissolves in nitric acid. 

The reaction commences at a temperature above 400° C., before the melting temperature is reached, and the fused product therefore always contains some arsenious oxide.1 When heated in hydrogen, the pentoxide is reduced first to arsenious oxide and then to free arsenic. Similar reduction occurs when it is heated with carbon or phosphorus with sulphur, arsenious sulphide is formed. Arsenic and metallic arsenides result when the pentoxide is heated with alkali metals,2 zinc, lead, iron or most other heavy metals mercury and silver react only at high temperature gold and platinum do not react. 

Neurotoxic chemicals and motor neuropathy Chlorpyrifos, dichlorvos (DDVP), EPN, n-hexane, 2-hexanone, lead, lead chromate, lead II thiocyanate, leptophos, methamidophos, mipafox, omethoate, parathion, trichlor-fon, trichloronate, triorthocresyl phosphate Neurotoxic chemicals and sensorimotor neuropathy acrylamide, allyl chloride, arsenic and compounds, arsenic trichloride, calcium arsenate, carbon disulfide, dichloroacetylene, ethylene oxide, gallium arsenide, lead arsenate, mercuric chloride, mercuric nitrate, mercurous nitrate, mercury, nitrous oxide, phenyl arsine oxide, thallium and soluble compounds, thallous nitrate... 

Hydrogen arsenide is an endothermic compound which is slowly destroyed at room temperature, and which under atmospheric pressure does not become detonating at any temperature, not even that developed by the electric spark if one detonates in hydrogen arsenide a fulminate-of-mercury cap, the gas undergoes not only a great rise in temperature, but also an energetic compression, and it decomposes with explosion. ... 

There is a problem with the widespread use of arsenic, cadmium, and selenium in electronic and photovoltaic devices. Cadmium mercury telluride is used in infrared-sensing night goggles. Cadmium sulfide, cadmium selenide, gallium arsenide, and analogues, are used in solar cells. If their use becomes widespread, then an efficient system of collecting used cells for reprocessing will be needed. Some workers feel that it will be better to use nontoxic silicon cells wherever possible. (Solar cells are discussed in Chap. 15.)... 

Alkyl iodides also react with metal arsenides on heating. Thus tetra-methyldiarsine, trimethylarsine, and tetramethylarsonium iodide are obtained from methyl iodide and sodium arsenide 168). Alkyl iodides and the arsenides of zinc, cadmium, or mercury give mainly compounds of the type (R4As)2Znl4 and R4AsHgl3 219, 220). These reactions are related to those described in Section II, A, 2 and probably to those in Section II, A, 5. 

Among a large number of minerals analysed by H. Rose (often in connexion with mineralogical investigations of his brother Gustav, but published independently) were micas," zeolites, spinels, aluminates, selenium minerals from the Harz,ii mercury selenide from Mexico, arsenides, antimonides, and... 

Phases formed on semiconductor surfaces can change the electrical properties in an uncontrolled, deleterious fashion. Oxide passivation layers on compound semiconductors (e.g., mercury cadmium telluride IR detectors or gallium arsenide solar cells) can be grown to impart protection to the surfaces and to stabilize electrical properties by preventing uncontrolled reactions. 

Detector. The radiation is detected by infrared-sensitive semiconductors, such as indium gallium arsenide (InGaAs) or mercury cadmium telluride (HgCdTe, but often abbreviated MCT). Infrared light striking these materials can promote electrons into conduction, allowing the radiation to be detected as an electrical current. 

While group III-V (e.g., gallium phosphide and gallium arsenide) and group II-VI (e.g., mercury cadmium tellurium) semiconductor devices are far less common than silicon semiconductors, CVD operations for them have certain chemistries unique in semiconductor manufacturing.[4 l-[43] Halide CVD processes used in the manufacture of some III-V devices utilize arsenic trichloride and phosphoms trichloride as source chemicals.[ 2][ l... 

The material composition of the FPAs determines the detectable IR-spectral frequency range. Many types of detectors are available, ranging from the commonly used indium antimonide (InSb) for near IR and mercury cadmium telluride (HgCdTe, MCT) for the mid IR to the more exotic silicon arsenide (Si As) [10] and uncooled barium strontium titanium (BST) [11]. Mid-IR imaging using MCT FPAs [12] has been the most popular in terms of the number of studies performed, due to its ability to provide access to the molecular-fingerprint region. 

Operating wavelength of the detector should be as close to the cutoff wavelength (Ico = hc/Eg) as possible. This requirement is easiest to meet in three-compound semiconductor materials with continually adjustable bandgap, e.g., mercury cadmium telluride (Hgi- cCd cTe) [8], mercury zinc telluride (Hgi- cZn cTe) [69-71], lead tin telluride Pbi Sn Te [72, 73], and indium arsenide antimonide (Ini - cAS cSb) [74] which for x = 0 reduces to indium antimonide, InSb. 

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