Halides of the Type

The chloride compound is obtained by electric discharge in a mixture of PC13 and H2. Preparation of P2I4 can be carried out by the reaction of I2 with a carbon disulfide solution of white phosphorus. 

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Rearrangement is especially prevalent with primary alkyl halides of the type RCH2CH2X and R2CHCH2X Aluminum chloride induces ionization with rearrangement to give a more stable carbocation Benzylic halides and acyl halides do not rearrange... 

Imido chalcogen halides of the type RNEC12 (E=S, Se, Te) provide an interesting illustration of the reluctance of the heavier chalcogens to form -N=E< double bonds. The sulfur derivatives RNSX2 (X=F, Cl) are stable, monomeric compounds. 

For instance, the halides of the type MXn which crystallize with layer... 

This synthetic method is of great importance in the synthesis of silicon amides. Halides of the type R SiCL,. (x = 0, 1, 2, 3) react with ammonia or primary and secondary amines to give the corresponding amides.17"24 Again, with sterically demanding amines only partial halide displacement is possible (equations 6 and 7).22,23... 

A number of oxides and halides of the type AB2 and AB3 form such polymeric compounds. 

All of the binary tetrahalides of carbon, silicon, germanium, and tin have been made, and many mixed halides (of the type SiCl2F2) have also been characterized. Except for SnF4 (the most saltlike of the group), all of the tetrahalides are volatile. It is interesting (and not easily explained) that aside from CF4 and SiF4, the tetrahalides of silicon boil at lower temperatures than those of carbon. 

Aluminum alkyl halides of the types R2A1X and RA1X2 are halide-bridged dimers in which, unlike Al2Me6, Al is surrounded by an electron octet. They are stronger Lewis acids than the trialkyls. The sterically very crowded compounds mes MX2 are monomeric they fail to give complexes with Et20 (M = Al, Ga, In X = Cl, Br).27... 

The smallest and perhaps the most important ones are the cyclotrisilanes,103 -germanes,104 -stannanes,105 and their mixed compounds.106 These are normally prepared by reaction of halides of the type R2EX2 with sodium or lithium naphthalenide, as in... 

Cyclooctatetraenyl lanthanide(III) halides of the type [(COT)Ln(/x-Cl)(THF)2]2 (Figure 77a) are the most important precursors for the preparation of other half-sandwich (see Half-sandwich Complexes) and mixed sandwich complexes with cyclooctatetraenyl ligands. These complexes are readily accessible by reacting anhydrons lanthanide trichlorides with K2[C0T] in a molar ratio of 1 1. The compounds consist of centrosyimnetric, chloro-bridged dimers with... 

The yields of dialkylacetates are 74-82% when R and R are combinations of n-, iso-, and s-butyl groups. This interesting cleavage has been used to prepare ethoxy esters from ethoxy halides of the type CjHjOfCHjl jX as well as a-methyladipic ester from the corresponding cyclic /3-keto ester (83%). ... 

Phenob. Organomcrcury halides of the type ArHgX react with diborane in THF under normal hydroboration procedures to give intermediate organoboranes which are not isolated but oxidized with alkaline hydrogen peroxide to give phenols in good yield. 

Structural Data of Chalcogen Halides of the Types XYj and X2Y2... 

Mercury di-isobutyl and di-isoamyl react with halogens to form halides of the type RHgX, and mercury diethyl gives similar results... 

Many polyhalides of alkali metals are known, the most important being the tri-iodides and the very stable mixed halides of the type MICl. Lithium... 

The linear connection [3] between the reduction potential of N,N-dimethylhydra-zones and their rate of cleavage [vide infra] supports the analogy with the reduction of vinylic halides. The analogy is further substantiated by the fact that vinyl halides of the type RCH=CR"Y form acetylenic compounds RC=CR" by a base-induced elimination on reduction in aprotic medium [2], analogously to the formation of nitriles from RCH= NY under similar conditions [4]. 

The principal valence of Group IV elements is 4, each element of the group except lead forming its principal series of compounds in the quadrivalent state. Valences of 2 are common, and 3 occasional. The quadrivalent halogen compounds of most of the elements form characteristic double derivatives with the alkali halides, of the type M12MlTX. These compounds, especially the fluorides, are of much importance. 

Pentacovalent Antimony Halides and Related Compounds. Antimony halides of the types RSbX4, R2SbX3, R3SbX2, and R4SbX, where X is a halogen, are known, but compounds of the first type have only been isolated and characterized where R is aryl. Tetrachloromethylantimony has been prepared at — 70°C, but not isolated (167) ... 

Haloarsoranes. Halides of the types RAsX R AsX R AsX, and R4AsX are known. The R4AsX compounds are ionic in nature and are discussed under arsonium salts. The tetrahalides are unstable compounds which frequently decompose on standing and are readily hydrolyzed in moist air to form arsonic acids. Aryltetrachloroarsoranes are readily prepared from aryldichloroarsines in an atmosphere of dry chlorine (142). Tetrafluorophenylarsorane [650-44-2], C6H5AsF4, has been prepared from phenylarsonic acid and sulfur tetrafluofide (143) ... 

Halides of the type AX6, where A is P, As, Sb, or Bi, and X is F, Cl, Br, or I, may generally be obtained by interaction of the elements. It is also possible to react AX3-type compounds with the corresponding halogen, and this is particularly useful when X = F. The halides SbF6 and BiF6 are made in this way. The compounds SbBr6 (cf. Section II,A,2), Sbl6, and arsenic(V) and bismuth(V) halides other than the fluorides are unknown. 

All halides of the type AX6 are very hygroscopic and are hydrolyzed by water. Bismuth pentafluoride, a white solid, becomes yellow with the least trace of water and readily fluorinates other substances, with reversion to BiF3. 

The group of halides of the type AX 3 includes some which have been known for 300 years. Antimony trichloride was described by Glauber in 1648 and bismuth trichloride by Boyle in 1664 (1j)5). The other halides were also discovered many years ago. Although they have since been widely studied, their properties are not known in every detail. The physical properties recorded in the literature show some discrepancies. 

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