Mercury arsenites

Mercury Arsenites.—Mercurous Orthoarsenite, Hg3As03, may be obtained by treating a solution of mercurous nitrate with one of sodium orthoarsenite6 or with a solution of arsenious oxide in 50 per cent, alcohol 6 in the latter case the mercurous nitrate solution should be acidified with nitric acid and sufficient alcohol added to produce a slight turbidity. The precipitate is pale yellow, but rapidly turns brown on exposure to air. It is slightly soluble in water, being slowly decomposed with separation of mercury. It is also decomposed by hydroxides and carbonates of alkali metals and of barium, and by ammonia. It dissolves in acids, but when these are dilute, basic salts gradually separate. 

Incompatibles.— Lime-water alkalies, and their carbonates the acetate of lead sulphates of iron, zinc, and copper perchloride of mercury arsenites of potash and soda and all vegetable astringents. 

Blakley BR, Sisodia CS, Mukkur TK. 1980. The effect of methyl mercury, tetraethyl lead, and sodium arsenite on the humoral immune response in mice. Toxicol Appl Pharmacol 52 245-254. 

In spite of the fact that ISEs for more than 60 ions have been described so far, recent findings imply that these ISEs should be re-characterized and re-optimized for trace level applications [19]. The list of ISEs with low-level LODs needs to be expanded either by re-characterization of existing ionophores or by synthesis of new ones. Important ions for which low LODs have yet to be demonstrated are, for example, mercury, chromium, nickel, arsenate and arsenite ions. Hopefully, synthetic chemists will rise to the challenge and new, selective ionophores will be developed that will achieve this goal. 

The impact of some metals is strongly related to their chemical form rather than to their total concentration. For instance, arsenic is generally toxic in both its As(III) arsenite and As(V) arsenate forms, but is nontoxic in its organic forms, such as arsenocholine. Mercury, on the other hand, is toxic in all forms but is substantially more toxic as methyl mercury than it is in the elemental state. Chromium in the Cr(III) oxidation state is less toxic and less soluble than it is in the Cr(VI) state. 

Shumilla JA, Wetterhahn KE, and Barchowsky A. 1998. Inhibition of NF-kB binding to DNA by chromium, cadmium, mercury, zinc, and arsenite in vitro Evidence of a thiol mechanism. Arch Biochem Biophys 349(2) 356-362. 

Attention is directed to the fact that arsenites are reduced in alkaline solution by aluminium, Devarda s alloy, etc., to arsine, which blackens mercury(I) nitrate paper and also gives a positive tannic acid-silver nitrate test. Hence neither the mercury(I) nitrate test nor the tannic acid-silver nitrate test for ammonia is applicable if arsenites are present. 

It must be emphasized that the mercury(I) nitrate paper test for ammonia is not applicable in the presence of arsenite. Arsenite is reduced by alkaline reducing agents to arsine, which blackens mercury(l) nitrate paper. The tannic acid-silver nitrate test (Section 111.38, reaction 7) may also be used this test is likewise not applicable in the presence of arsenite. 

The carbonates, sulphates, and borates are decomposed. The sulphides of the alkalies and alkaline earths are decomposed while the sulphides of arsenic, antimony, molybdenum, zinc, cadmium, tin, iron, lead, copper, mercury, and palladium are not attacked. Cobalt sulphate is not attacked, while the sulphates of the alkalies and alkaline earths are attacked and dissolved. Alkali tungstates, ammonium arsenite and arsenate, copper arsenite, ammonium magnesium arsenate, ammonium molybdate and vanadate, potassium cyanide and ferrocyanide are decomposed. Paraffin is not attacked shellac, gum arabic, gum tragacanth, copal, etc., are decomposed. Celluloid is slowly attacked. Silk paper, gun cotton, gelatin, parchment are dissolved. M. Meslans 22 has studied the esterification of alcohol by hydrofluoric acid. 

Many chemicals can also exist as various species or states of ionization. For example, nitrogen can exist as nitrate, nitrite, or ammonia, arsenic can exist as arsenate or arsenite, and lead can exist as lead nitrate or lead chloride. The species or ionization state may depend upon abiotic variables such as soil or water pH, amount of dissolved oxygen in the water, and presence of other chemicals. Alternatively, bacteria and fungi may change the species or ionization state of a chemical. For example, bacteria can convert arsenite to arsenate, and add methyl groups to ionic mercury to produce methylmercury. 

ARSENIOUS ACID or ARSENIOUS OXIDE or ARSENITE (1327-53-3) AsjOj Noncombustible solid. Reacts, possibly violently, with acids, aluminum, aluminum chloride, chlorine trifluoride, chromic oxide, fluorine, fluorides, halogens, hydrogen fluoride, mercury, oxygen fluoride, phosphorus pentoxide, rubidium acetylide, sodium chlorate, sodium hydroxide, sulfuric... 

BROME (French) (7726-95-6) A powerful oxidizer. Violent reaction with reducing agents. Can cause fire and explosions in contact with organic or other readily oxidizable materials. Contact with water or steam forms hydrobromic acid and oxygen. Contact with aqueous ammonia, acetaldehyde, acetylene, acrylonitrile, hydrogen may cause violent reactions. Anhydrous material reacts violently with aluminum, titanium, mercury, or potassium wet material reacts with other metals. Incompatible with many materials, including alcohols, antimony, alkali hydroxides, arsenites, azides, boron, calcium nitrite, cesium monoxide, carbonyls, dimethyl formamide, ethyl phosphine, fluorine, ferrous and mercurous salts, metals. 

---