Crystal mercury compounds

Alkali-mctal-mercury compounds decompose rapidly in O2 or moisture and must be prepared in melt atmospheres or under vacuum. To prepare NaHg, NaHgj and Na,Hg2, known amounts of Hg and Na are flushed with N2. The reaction is exothermic, and mixing is carried out slowly, homogeneity being achieved by shaking. An excess of Na or Hg is necessary for crystal formation. ... 

Similarly, dilithiation of 2-(4-bromophenoxy(ethanol in the presence of magnesium 2-ethoxyethoxide followed by reaction with 0.5 equiv. of HgCl2 afforded the corresponding diarylmercury compound 4-(H0(CH2)20)-C6H4)2Hg 26 whose crystal structure has been determined (Equation (12)).47 In addition to these alcohol and ether derivatives, thio- and phosphinoaryl mercury compounds have also been prepared. Thus, the dilithium salt... 

There are a number of books and articles on general aspects of the coordination compounds of mercury annual surveys are published in Coordination Chemistry Reviews5 and the Annual Reports on the Progress of Chemistry, Section A (Inorganic Chemistry—Mercury).6 McAuliffe s book The Chemistry of Mercury covers the literature up to May 1975.7 The coordination chemistry of mercury(II) halides has been summarized by Dean, covering papers up to 1977.8 A review of dimercury(I) coordination compounds was published by Brodersen in 1981,9 and in the same year Grdeni6 reviewed bonding in the crystal structures of mercury compounds.10... 

There are mercury compounds with mercury oxidation numbers lower than +1, e.g. +0.5,16,21 +0.6713,15,27 or +0.35.18,20 Yellow crystals of Hg3(AsF6)2 have been formed by the reaction of metallic mercury with AsFs in liquid S02.13 X-Ray structure determination showed a linear polycation Hg+—Hg—Hg+ with Hg—Hg distances of 255 pm.15 Metallic mercury and SbF5 react in liquid S02 to form Hg3(Sb2Fu)2.15,23 The Hg—Hg distances in the complex Hg3(AlCU)2 are 256 pm 14 the Hg—Cl distances are 251 and 256 pm the Hg—Hg—Hg angle is 174°. Dark red crystals of Hg4(AsF6)2 were obtained in liquid S02. This coordination compound contains centrosymmetric Hg4+ ions, which are connected to chains (see l).21... 

The colorless zinc compound, Zn(CisH6)2, which sublimes at 160° under partial decomposition, is obtained in small yield from zinc chloride and cyclopentadienyl sodium in diethyl ether however, the less stable cadmium compound decomposes, with separation of cadmium, under these conditions (55). The mercury compound, Hg(CsH5)2, is produced in 20% yield by the action of the sodium derivative on mercuric chloride in tetrahydrofuran (215). The action of cyclopentadiene on the complex K2(HgI ) in aqueous alkaline solution results in the precipitation of a mixture of CsHsHgl and Hg(CsH6)2, from which the latter compound may be obtained in good yield by extraction with a mixture of tetrahydrofuran and petroleum ether (62). It forms pale yellow crystals which begin to decompose at about 60° and which melt at 83-85°. The compound is readily soluble in most solvents it decomposes slowly even when kept in the dark at room temperature it is insoluble in water and reacts with neither water nor bases. On the other hand, decomposition occurs in dilute hydrochloric acid. It converts ferric chloride to ferrocene quantitatively, and it yields an adduct with maleic anhydride (215). 

Macrocyclic mercury compounds have also been investigated by Shur et al. (98). Receptor 35 was proven to complex halide ions by, 99Hg NMR studies but complex isolation failed. On fluorination of the benzene rings yielding receptor 36, complex isolation became possible (99). As seen from the crystal structure of 36 (Fig. 3), each bromide ion is coordinated to six mercury atoms and is sandwiched between two mercuiy macrocycles. The Hg—Br distances are 3.07-3.39 A, shorter than the van der Waals contact but longer than a covalent bond. Receptor 37 was also crystallographically proven to coordinate chloride ions (100). The crystal structure indicated one chloride ion bound above the plane of the macrocycle and one below it, both coordinated by all five mercury atoms (rHg C = 3.09-3.39 A). The chloride-chloride distance was short (3.25 A), probably only tolerated due to the presence of the mercury sandwich filling. ... 

Inorganic mercury compounds occur when mercury combines with elements such as chlorine, sulfur, or oxygen. These mercury compounds are also called mercury salts. Most inorganic mercury compounds are white powders or crystals, except for mercuric sulfide (also known as cinnabar) which is red and turns black after exposure to light. 

Mercury compounds prepared in this way (Table VIII) are strongly refractive liquids which crystallize in favorable cases. They dissolve readily in organic solvents and are stable to water. Since the mercury compounds can be obtained in a pure form (by distillation, recrystallization) they are actually isolated as an intermediate step in carbosilane synthesis. This results in the removal of all the impurities arising from the various steps in the synthesis, a factor which is particularly important in making carbosilanes of higher molecular weights, where purification becomes more difficult as the molecular weight increases and by-products tend to have an unfavorable effect on the synthesis. 

Crystallization bp Sublimation.—Volatile solids, as iodine, camphor, several metallic chlorides and mercurial compounds, arsenic, benzoic acid, iodide of lead, etc., when heated as directed in st(bHma/ton. yield vapors which, in cooling, take the form of crystals. 

Drefahl, Seeboth, and Degen dissolved 4/-ureido-4-stilbenecarbaldehyde diethyl mercaptal in aqueous acetone and stirred the solution with HgCl2 and HgO at room temperature. The mercury compounds were filtered off after 1 h. On addition of water, 4 -ureido-4-stiIbene-carbaldehyde crystallized in 89 % yield.98... 

PHYSICAL PROPERTIES most inorganic mercury compounds are white powders or crystals mercuric sulfide (cinnabar) is red and turns black when exposed to light insoluble in hydrochloric or similar acids soluble in nitric acid and hot concentrated sulfuric acid water soluble salts include mercuric chlorate, cyanide, chloride and aeetate oxides, sulfates and most other common salts, including mercurous chloride, are sparingly soluble or deeomposed in water appearances vary from eolorless crystals to yellow, red (oxide, sulfide, iodide), and brown or black (sulfide) MP (-39°C, -38°F) BP (357 C, 674 F) DN (13.534 gW at 25°C) SG (13.5) VD (not applicable) VP (0.0012 mitiHg at 20°C). 

The zinc and cadmium organosilyl compounds are about equally unstable, in sharp contrast to the mercury compounds. The reaction of lithium tetrakis(trimethylsilyl) aluminate with zinc acetate in diethyl ether yields (25 %) bis(trimethylsilyl) zinc [435]. This compound can be kept for about three weeks under an inert gas at — 20 °C. The reaction of lithium tetrakis(trimethylsilyl) aluminate with cadmium acetate forms bis(trimethylsilyl) cadmium [435] (27%, very unstable, sensitive to light). Bis(tri-t-butylsilyl) cadmium [436] (m. p. 140 °C, slightly yellowish crystals which turn greenish black on exposure to air) can be obtained from tri-r-butylsilane and diethylcadmium (Eq. 3.230) ... 

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