Alkali-Metal-Mercury Compounds

Alkali-metal-mercury compounds decompose rapidly in O2 or moisture and must be prepared in melt atmospheres or under vacuum. To prepare NaHg, NaHg2 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. ... 

The alkali metal-graphite compounds are extremely reactive. They ignite in air and may react explosively with water. In the controlled reaction with water or alcohol only alkali hydroxide and hydrogen result there is no acetylene or any other hydrocarbon. Fredenhagen concluded from this that the compounds could not be carbides. Mercury dissolves the alkali metal out of the lattice. When treated with liquid ammonia, CgMe gives up only a third of the alkali metal and takes in its place two molecules of ammonia (see Section IIIA4). 

Neta.1 Ama.lga.ms. Alkali metal amalgams function in a manner similar to a mercury cathode in an electrochemical reaction (63). However, it is more difficult to control the reducing power of an amalgam. In the reduction of nitro compounds with an NH4(Hg) amalgam, a variety of products are possible. Aliphatic nitro compounds are reduced to the hydroxylamines, whereas aromatic nitro compounds can give amino, hydra2o, a2o, or a2oxy compounds. 

Reductive dehalogenation cannot be completely controlled, and mostly complicated mixtures were formed which are difficult to separate. Salt elimination opens the possibility of a reaction aimed at polysilane formation. Some examples are shown in Fig. 2. The key compounds are the alkali metal cyclosilanes, which we have isolated via the mercury compounds by the action of sodium/potassium alloy and used for the first time [13]. 

The lack of homopolyatomic anions for elements to the left of group IV In Table I is noteworthy. Zlntl reported no success with reactions of alkali metal alloys of the copper and zinc family elements and of thallium with liquid ammonia, and the generally stabilizing effect of crypt has not been evident In our own Investigations of alloys of mercury and thallium. On the other hand. It is possible to Isolate a white crypt-potassium gold compound from ammonia solutions at low temperatures which decomposes to elemental gold (+ ) above about -10°C (30). 

All the allylic compounds were prepared by reacting the appropriate mercury allyl compounds with either a film of the alkali metal, or finely divided lithium, in an evacuated apparatus fitted with breakseals, a glass filter, and a nmr tube. The solvent was THF except where noted. 

In the present study, the Jg g values in the allyl alkali metal compounds are near 60 hz for the K and Cs compounds, and a little lower for the Li compound, table I. Allyl mercury is not a delocalized system, and if any exchange occurs between the two ends of the allyl radical it is slow on the NMR time scale. Consequently and Jg Y are measurable and are h2 and 69 hz... 

Again several alkyls add—molybdenum, chromium, iron, cobalt, nickel, the alkali metal alkyls and aluminum alkyls react. A tin alkoxide has recently been studied by Russian workers and found to add to acetylenes. Mercury chloride, of course, adds and two cobalt—cobalt bonded compounds add to acetylene. The second is questionable because it dissociates in solution and the reaction may be a radical reaction, one cobalt adding to each end of the triple bond. 

Rubidium metal alloys with the other alkali metals, the alkaline-earth metals, antimony, bismuth, gold, and mercury. Rubidium forms double halide salts with antimony, bismuth, cadmium, cobalt, copper, iron, lead, manganese, mercury, nickel, thorium, and zinc. These complexes are generally water insoluble and not hygroscopic. The soluble rubidium compounds are acetate, bromide, carbonate, chloride, chromate, fluoride, formate, hydroxide, iodide,... 

Nonpolar molecular compounds dissolve in nonpolar solvents. Polar molecular compounds and ionic compounds may dissolve in polar solvents. Metals dissolve in other molten metals. These can range from copper, silver, gold, alkali metals dissolving in mercury at room temperature, to chromium, molybdenum, and tungsten dissolving in molten iron. 

Hg(CNO)2 is decomposed by heat (equation 8).4 It crystallizes in the orthorhombic form and contains linearly coordinated mercury.21 It reacts with alkali metal fulminate solutions to form the highly explosive compounds M2Hg(CNO)4 (M = K, Rb, Cs) with larger cations such as Ph4As+ more stable complexes are formed.219,220 Besides the homogeneous anionic mercury(II) fulminato complexes there are a few mixed species with unknown structures, e.g. Na Hg(CNO)2X (X = Cl, Br) or Na2S203-2Hg(CNO).221... 

CARBIDES. A binary solid compound of carbon and another element. The most familiar carbides are those of calcium, tungsten, silicon, boron, and iron (cemcntitc) Two factors have an important bearing on the properties of carbides (1) the difference in electronegativity between carbon and the second elemenl. and (2) whether the second element is a transition metal. Saltlike carbides of alkali metals are obtained by reaction with acetylene. Those ohlained from silver, copper, and mercury sails are explosive. See also Carbon and Iron Metals, Alloys, and Steels. 

Linearly connected polycyclic silanes are usually made by salt elimination reactions, whenever the cyclosilanyl alkali metal compound involved is stable enough. Otherwise, the photochemical cleavage of bis(cyclosilanyl)mercury compounds may be employed. An... 

As an alternative to condensation of dichlorosilanes by alkali metals, it is possible to synthesize poly silanes by the reaction of preformed dilithio compounds with dichlorosilanes. An early synthesis of a copolymer by this route is illustrated in equation (19).10 (see also Section 5.9.2). Finally, poly(phenylmethylsilylene) has been made by thermal decomposition of a silyl-mercury polymer36 (equation (20)). 

The chemistry of a class of organometallic compounds that contain a linkage between two different metallic and/or metalloidal elements has recently been the subject of considerable study (195, 207), but only very little interest has been shown in such compounds with the silicon-silicon-metal bond. Only a few derivatives of mercury and alkali metals are known. 

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