Mercuric iodide, preparation

Potassium mercuric iodide.—Prepare the reagent by adding to a few drops of a solution of mercuric chloride a solution of potassium iodide until the precipitate first formed is dissolved. Add to 2 cc. of egg-white solution a drop of dilute hydrochloric acid and a drop of the reagent. 

Mercuric chloride is widely used for the preparation of red and yellow mercuric oxide, ammoniated mercury/7(9/USP, mercuric iodide, and as an intermediate in organic synthesis. It has been used as a component of agricultural fungicides. It is used in conjunction with sodium chloride in photography (qv) and in batteries (qv), and has some medicinal uses as an antiseptic. 

Mercurous Iodide. Mercurous iodide [7783-30 ] Hg2l2, is a bright yellow amorphous powder, extremely insoluble in water and very sensitive to light. It has no commercial importance but may be prepared by precipitation, using mercurous nirate and potassium iodide. Care must be taken to exclude mercuric nitrate, which may cause the formulation of the water-insoluble mercuric iodide. 

The range of uses of mercuric iodide has increased because of its abiUty to detect nuclear particles. Various metals such as Pd, Cu, Al, Tri, Sn, Ag, and Ta affect the photoluminescence of Hgl2, which is of importance in the preparation of high quaUty photodetectors (qv). Hgl2 has also been mentioned as a catalyst in group transfer polymerization of methacrylates or acrylates (8). 

The reaction with mercury gave as the initial product trifluoromethyl mercuric iodide, CFsHgl, a white crystalline solid very similar to methyl mercuric iodide. From it, the free base, CFjHgOH, and a number of salts were prepared. 

Mercuric bromide and mercuric iodide yield the same type of compounds. The stability of these, however, is less than that of the chlorides. The fluorine analogue to fusible precipitate has been prepared,7 to which the composition Hg(NHs)F is given. Dimercuric fluoramide, (HgF)2NH.H20, has also been prepared. 

Di-iodo-diethylenediamino -chromic Salts are derived from di-iodo-diethylenediamino-ehromiciodide mercuric iodide, [Cr en2I2]I.HgI2, which is prepared by decomposing bromo-bisaquo-salts with hydriodic acid and mercuric iodide. It crystallises in very green leaflets, and is almost insoluble in water. The double salt is decomposed by hydrogen sulphide. The iodide is unstable, and in solution very readily decomposes.3... 

Hydrates are merely one form of a double salt, and it often happens that other double salts as well as hydrates exhibit transition or decomposition points. Salts, whether simple or double, that have transition points at which color changes occur are of special interest. Mercuric iodide is a striking example of such a simple salt and is easily prepared by double decomposition. The preparation of a few other examples will be described. 

Many other methods of preparation have been employed. For example, the triiodide is formed when arsenious oxide,5 or a mixture of this oxide with sulphur,6 is heated in iodine vapour or when arsenious oxide is heated with iodine,7 hydriodic acid,8 a mixture of potassium iodide and acetic acid,9 or a mixture of potassium iodide and potassium hydrogen sulphate.10 When arsenic disulphide and iodine, in the proportions 1 As Ss 3la, are heated together, arsenic triiodide is formed.11 When arsenic trisulphide is fused with an excess of iodine, the product is soluble in carbon disulphide and the solution on evaporation deposits arsenic triiodide, then a sulphiodide and finally sulphur with excess of sulphide the product is the sulphiodide, AsS2I. If a solution of iodine in carbon disulphide is added to arsenic di- or tri-sulphide, the triiodide and sulphur are formed. The triiodide is also produced when a mixture of the trisulphide and mercuric iodide is heated 12. when hydriodic... 

Prepared by reaction (I) of iodine and mercuric oxide (see also Mercury) suspension in water, mercuric iodide being simultaneously formed. (2) of sodium hypoiodite and an acid, excess acid yielding iodine. 

P. Lemoult obtained phosphorus trisiodomercuriate, P(HgI)8, by the action of phosphine, diluted with hydrogen or carbon dioxide, on a dil, soln. of potassium iodomercuriate. The product is washed and dried in vacuo. It is slowly decomposed by warm water and rapidly by alkali-lye. Nitric acid and aqua regia decompose it violently. F. Venturoli prepared "yellow phosphorus iodobisiodo-mercuriate, I.P (Hgl)2, by the action of phosphorus on an alcoholic soln. of potassium iodide. The product is decomposed by heat into phosphorus, and mercurous and mercuric iodides. 

We repeated and extended a part of Boyd s experiments using modem techniques and instrumentation facilities. We used two different potentized drugs, namely Mercuric chloride 30 and Mercuric iodide 30, and prepared them both in double distilled water and the usual medium of 90% ethanol. The purpose was to see whether the metal ion or the halide ion could play any individual role in altering the enzyme activity. The efficacy of the two media, water and aqueous ethanol, was also tested by these experiments. It is the experience of homeopathic physicians and pharmacists that potentized homeopathic drags prepared in aqueous ethanol keep their activity for a pretty long time. We wanted to test whether the pure aqueous preparation of a homeopathic potency could keep its activity as long as the hydrated... 

This procedure is a modification of one described by Cortese.4 Allyl chloride is employed rather than allyl bromide because of its low cost. Biallyl has been prepared by the action of sodium 6 or aluminum 6 on allyl iodide from allyl mercuric iodide by dry distillation 7 or by the action of potassium cyanide solution 8 and by the action of magnesium on allyl bromide,4-9 on allyl chloride,4-10 on allyl iodide,11 or on 1,2,3-tribromopropane.12... 

Incidentally it may also be mentioned that Sand and Singer 4 have prepared alcohols electrolytieally by reducing the mercuric-iodide compounds of alcohols. The cathode is a large sheet of platinum which is immersed in the solution of... 

Mercury diphenyl has been prepared in a number of ways. The most important methods are by the action of sodium on a mixture of bromobcnzene and mercuric chloride 1 from sodium amalgam and phenyl mercuric iodide 2 by the interaction of phenyl mercuric bromide and potassium sulfide2 or phenyl mercuric acetate and sodium stannite 3 from phenyl magnesium bromide and mercuric chloride 4 by the action of phenyl hydrazine on mercury compounds 5 from mercuric chloride and phenyl arsenious oxide 6 and from diphenyl mercuric ammonium acetate and sulfur compounds.7... 

Halogen-substituted mercuracarborands can be prepared from their halogenated substituted carborands <2001AGE2124>. f/oro-9,12-l2-l,2-C2B8Hio 22 can be deprotonated and treated with mercuric iodide to give the bis-iodo-tetramer 23 in 78% yield (Equation 3). The starting bis-iodo-carborane 22 is prepared by electrophilic iodinaton of the 9,12-vertices of 1,2-carborane. 

Silver iodide is only slightly soluble in ammonia, but dissolves in sodium thiosulphate, concentrated hydriodic acid, and saturated solutions of potassium iodide.7 It forms a series of double salts with silver bromide,8 with mercuric iodide, and with the iodides of the alkali-metals.10 Double compounds of silver iodide and ammonia of the formulae AgI,8NH3 (6-92) AgI,l NH3 (7-25) AgI,NHs (8-56) AgI,2NHs (7-05) and AgI, NH3 (11-59) have also been prepared,11 the figures in parentheses indicating the calculated heats of formation in large calories. 

The reagent is prepared by dissolving 10 gm. potassium iodide in 70 ml. water and adding 14 gm. mercuric iodide. 

Iodide,—Combination takes place between ethyl iodide and metallic mercury when exposed to diffused daylight, with formation of ethyl mercuric iodide.This may also be obtained by the addition of an alcoholic solution of iodine to ethyl mercuric hydroxide, or from mercury diethyl by boiling for one or two days with allyl iodide. iVnother preparation from mercury diethyl is to heat for several days at 120° C. with iodoform, when the iodide, ethyl iodide, ethylene, and acetylene are formed. ... 

Propargyl mercuric iodide forms a yellow mass it is prepared in a similar way to the allyl compound. ... 

Butene mercuric iodide, C H Hgl.—When potassium iodide is used in the above preparation, Sand and Hofmann state that a butanol compound is not obtained, but the butene derivative. It crystallises in spears from ether, and prisms from benzene or carbon disulphide. All the above substances with 20 per cent, hydrocliloric acid give a quantitative yield of olefine and mercuric salt. 

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