Mercury II iodide

Addition of mercury(II) chloride solution to a solution of an iodide gives a scarlet precipitate of mercury(II) iodide, soluble in excess of iodide ... 

Merkuri-jodid, n. mer curic iodide, mercury (II) iodide, -nitrat, n. mercuric nitrate, mercury-(II) nitrate. -oxyd, n. mercuric oxide, mercury (II) oxide, -rhodanid, n. mercuric thiocyanate, mercury(II) thiocyanate, -salz, n. mercuric salt, mercury (II) salt, -sulfati n. mercuric sulfate, mercury (II) sulfate, -sulfidt ti. mercuric sulfide, mercury (II) sulfide. -sulfozyamd, n. mercuric thiocyanate. 

Add 3 drops of chloroform or 10mgL 1 of mercury(II) iodide these compounds improve the keeping qualities of the solution. 

Discussion. J. Nessler in 1856 first proposed an alkaline solution of mercury(II) iodide in potassium iodide as a reagent for the colorimetric determination of ammonia. Various modifications of the reagent have since been made. When Nessler s reagent is added to a dilute ammonium salt solution, the liberated ammonia reacts with the reagent fairly rapidly but not instantaneously to form an orange-brown product, which remains in colloidal solution, but flocculates on long standing. The colorimetric comparison must be made before flocculation occurs. 

The following is an alternative method of preparation. Dissolve lOOg mercury(II) iodide and 70g potassium iodide in 100mL ammonia-free water. Add slowly, and with stirring, to a cooled solution of 160 g sodium hydroxide pellets (or 224 g potassium hydroxide)in 700 mL ammonia-free water, and dilute to 1 L with ammonia-free distilled water. Allow the precipitate to settle, preferably for a few days, before using the pale yellow supernatant liquid. 

Remarkable cis diastereoselectivity occurs in the addition of l-alkoxy-l-(trialkylsilyloxy)-ethenes to y-silyloxy-substituted cyclo-2-alkenones using mercury(II) iodide as a catalyst265,266. C-C Bond formation syn to the electron-withdrawing silyloxy substituent has been attributed to the stabilization of the emerging cr -orbital at the -carbon by interaction with the ct(CH) bond at the y-carbon atom267. 

A solution of 4.5 g (19.9 mmol) 4-(fm-butyldimethylsilyloxy)-2-cyclohexenone and 452 mg (1 mmol) of mercury(II) iodide is stirred at r.t. for 15 min and then cooled to — 78 °C. 5.03 g (24.8 mmol) of 1-ethoxy-1-(tm-bulyl(iimethylsilyloxy)ethene are added dropwise during 15 min. The mixture is stirred at — 78 °C for 2 h, quenched with 302 mg (3 mmol) of triethylamine and allowed to warm to r.t. The mixture is filtered through a short (3 cm) column of silica gel (deactivated with a 5% triethylamine solution in hexane/ethyl acetate, 10 1) eluting with hexane/ethyl acetate (10 1) and concentrated in vacuo. Purification of the crude material by flash chromatography (silica gel, hcxanc/cthyl acetate 30 1) gave the adduct as a colorless oil yield 7.98 g (18.7 mmol, 94%) d.r. (cisjtrans) 95.2 4.8. 

Manganese trichloride oxide, 4141 Manganese trifluoride, 4335 Mercury(II) bromide, 0269 Mercury(I) fluoride, 4312 Mercury(II) iodide, 4602 Molybdenum hexafluoride, 4365 Molybdenum pentachloride, 4180 Neptunium hexafluoride, 4366 Osmium hexafluoride, 4370 Palladium tetrafluoride, 4347 Palladium trifluoride, 4341... 

Mercury(II) iodide is used as an analytical reagent, in Nesslers reagent for the analysis of ammonia. The compound also is used in ointments for the treatment of skin diseases. 

Mercury(II) iodide is precipitated in its yellow form by adding a stoichiometric amount of potassium iodide to an aqueous solution of mercury(II) salt (e.g., HgCb) ... 

Also, mercury (II) iodide is formed when mercury is rubbed with iodine moistened with ethanol. 

Mercury(II) iodide reacts with excess iodide ion forming complex tetraiodomercurate(II) ion, [HgG] ... 

In general, mercury(II) iodide forms neutral complexes of compositions M2(Hgl4) and MfHgls) with alkali and alkaline metal iodides. 

The bromo analog of the triruthenium-mercury cluster can be synthesized by following the identical procedure outlined in Section (B.1), by substituting mercury(II) bromide for mercury(II) iodide. Thin layer chromatography (TLC) must be used in the work-up of the bromo derivative to separate the desired product from [Ru3(CO)9(C2-f-Bu)]2Hg, which is formed to some extent. 

The symmetrical hexaruthenium-mercury cluster is synthesized using the procedure presented in Section B.1, varying only the amount of mercury(II) iodide added. 

The compound Ru3H(CO)9(C2-t-Bu) (1.243 g, 1.950 mmol) is treated with alcoholic potassium hydroxide (17.5mL of 0.128 M, 2.24 mmol) followed by mercury(II) iodide (0.444 g, 0.978 mmol) as outlined in the procedure in Section (B.l). The resulting solution is allowed to stir under a carbon monoxide atmosphere until a bright yellow precipitate forms. The reaction time is typically 30 to 45 min. Upon precipitation, the reaction mixture is evaporated to dryness under reduced pressure. The resulting residue is washed first with 50 mL of absolute ethanol and then with 25 mL of dichloromethane. The remaining yellow residue is recrystallized from hot THF. Yield 1.16-1.20 [81-84% yield based on Ru3H(CO)9(C2-t-Bu)]. 

Preparation of Mercury(II) Iodide. Prepare a 0.02 N solution of mercury(II) nitrate. Boil 2-3 ml of the solution, add an equal volume of a 0.02 N potassium iodide solution, and let the mixture stand to your next lesson. Filter off the precipitate (what is its composition ) through a paper filter, wash it with water, and dry it in a drying cabinet at 70 °C. What happens to the salt when it is kept in the air ... 

Zewail and co-workers have reported femtosecond laser experiments on the photodissociation of mercury(II) iodide (Hgl2) [151] ... 

The previous two chapters have provided several examples of reactions hydrogen reacting with oxygen to yield water, sodium reacting with chlorine to yield sodium chloride, mercury(II) nitrate reacting with potassium iodide to yield mercury(II) iodide, and so forth. We can write equations for these reactions in the following format ... 

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