Arsenic trifluoride

Arsenic pentafluoride can be prepared by reaction of fluorine and arsenic trifluoride or arsenic from the reaction of NF O and As (16) from the reaction of Ca(FS02)2 and H AsO (17) or by reaction of alkaH metal or alkaline-earth metal fluorides or fluorosulfonates with H AsO or H2ASO2F (18). 

Arsenic trifluoride (arsenic(III) fluoride), AsF, can be prepared by reaction of arsenic trioxide with a mixture of sulfuric acid and calcium fluoride or even better with fluorosulfonic acid. Chlorine reacts with ice-cold arsenic trifluoride to produce a hygroscopic soHd compound, arsenic dichloride trifluoride [14933-43-8] ASCI2F35 consisting of AsQ. and AsF ions (21). Arsenic trifluoride forms a stable adduct, 2AsF2 SSO, with sulfur trioxide and reacts with nitrosyl fluoride to give nitrosonium hexafluoroarsenate(V) [18535-07-4] [NO][AsFg]. 

Arsenic pentafluoride (arsenic(V) fluoride), AsF, is a colorless gas that condenses to a yellow Hquid its dielectric constant is 12.8 at 20 °C. It is formed by reaction of a mixture of bromine and antimony pentafluoride with arsenic trifluoride. The molecule is a trigonal bipyramid and is somewhat dissociated as indicated by vapor density measurements. 

Carbon disulfide gives an essentially quantitative yield of carbon tetralluoride and sulfur on reaction with sulfur tetrafluoride at 450 C in the presence of arsenic trifluoride as a catalyst. At lower temperature, bis(fnfiuoromethyl) polysulfides are formed [//] (equation 15). 

C09-0090. Sulfur trioxide has no dipole moment, but arsenic trifluoride has [i — 2.59D. Use Lewis structures to account for this difference in dipole moments. 

Fluorination of ClsP NMe-BCls (Section 2) by arsenic trifluoride results in the formation the well-characterized dimeric phosphazene (23) ... 

Last, but not least, there is to be mentioned, that in some cases a direct transformation of dichlorophosphates (see section 3.4.) into difluorophosphates by fluorination with elementary fluorine (In(P02p2)3, F (P02F2)3 40)) or with arsenic trifluoride at elevated temperature is possible 41). ... 

The oxide ignites immediately with ethanol at ambient temperature [1]. The liquid oxide (above 24°C) reacts very violently with methanol, dimethylformamide, dimethyl sulfite or dimethyl sulfoxide (also with arsenic trifluoride) and charring may occur [2],... 

ARSENIC TRI BROMIDE ARSENIC TRICHLORIDE ARSENIC TRIFLUORIDE ARSENIC PENTAFLUORIDE ARSINE... 

When heated in air at 800°C AS4S4 vapors begin to dissociate to AS2S2 which then ignites to form arsenic oxides. Ignition in chlorine produces arsenic chloride. Reaction with fluorine forms arsenic trifluoride. It is stable in water and also in the air at ambient temperatures. It does not react with hot concentrated HCl but is decomposed by nitric acid. It forms thioarsenite ion, AsS3 and elemental arsenic when warmed with caustic soda solution. Similar reaction occurs with sodium sulfide. 

Arsenic trifluoride is hydrolyzed by water. It reacts with chlorine gas at ice-cold temperature to form arsenic dichloride trifluoride, AsCbFs, a solid hygroscopic product that consists of the ions AsCh and AsFe. 

Reactions with fluorine and chlorine give arsenic trifluoride AsFs and arsenic trichloride AsCls, respectively. 

Heating phosphorus pentachloride with arsenic trifluoride ... 

Moissan reasoned that if he were trying to liberate chlorine he would not choose a stable solid like sodium chloride, but a volatile compound like hydrochloric acid or phosphorus pentachloride. His preliminary experiments with silicon fluoride convinced him that this was a very stable compound, and that, if he should ever succeed in isolating fluorine, it would unite with silicon with incandescence, and that therefore he might use silicon in testing for the new halogen. After many unsuccessful attempts to electrolyze phosphorus trifluoride and arsenic trifluoride, and after four interruptions caused by serious poisoning, he finally obtained powdered arsenic at the cathode and some gas bubbles at the anode. However, before these fluorine bubbles could reach the surface, they were absorbed by the arsenic trifluoride to form pentafluoride (18, 23). 

Ammino-arsenic Trifluoride.—A substance, of composition [As2(NiI3).]F0, is formed by acting upon arsenic trifluoride vapour with ammonia. It is a light white powder which is decomposed by water, with formation of an add solution.1... 

Tetrakis(phenyldifluorophosphine)nickel-(0) could also be obtained, using arsenic trifluoride in the presence of catalytic amounts of antimony pentachloride, or zinc fluoride as fluorinating agents. Yields as high as 50% could be obtained, but sizable decomposition on the process of fluorination of the chlorophosphine nickel-(0) complexes in solution could not be entirely suppressed. The marked instability of zerovalent nickel-phosphine complexes in solution in organic solvents, even under strictly anhydrous and anaerobic conditions, has been noted by several workers (16,20), but is still lacking a detailed explanation. A closer examination of the system carbon tetrachloride-tetrakis(trichlorophosphine)nickel-(0) (23) showed the main pa h of the reaction to consist in the formation of hexachloro-ethane with conversion of zerovalent into bivalent nickel, while the coordinated... 

Very little work has been done on fluoro derivatives of thiophenes. 2-Fluorothiophene was obtained in low yield from treatment of 2-iodothiophene with arsenic trifluoride. The action of fluoroboric acid on thiophenediazonium salts was unsuccessful. It may be useful for the preparation of 4-, 5-, 6- or 7-fluorobenzo[6]thiophenes from the appropriate amines. However, these are more conveniently prepared from fluorine-substituted benzenethiols by ring-closure reactions. For example 4,5,6,7-tetrafluorobenzo[6 Jthiophene was obtained by decarboxylation of the corresponding 2,3-dicarboxylic acid (equation 99) prepared by condensation of pentafluorobenzenethiol with diethyl acetylenedicarboxylate (Section 3.15.3.4.1). 2-Fluorothiophene has been prepared from 2-thienyllithium using perchloryl fluoride, and 2-fluorobenzo[ Jthiophene from the 2-lithio derivative in a similar manner (Section 3.14.3.9.1). 

Arsenic Trifluoride, AsF3, is formed when fluorine reacts with arsenic trichloride 1 or with the arsenides of the alkali or alkaline earth metals 2 by the action of anhydrous hydrofluoric acid or of acid fluorides on arsenious oxide 3 by the action of certain metallic fluorides, for example silver or lead fluoride on arsenic trichloride,4 or of ammonium fluoride on arsenic tribromide B and by the action of iodine pentafluoride on arsenic.6... 

The heat of formation of liquid arsenic trifluoride has been obtained 1 indirectly by determining the heats of dissolution of the trifluoride and of a mixture of arsenious oxide and sodium fluoride in about one litre of normal sodium hydroxide solution. The value obtained was 198,300 calories. Assuming Trouton s constant to be 21, the heat of vaporisation is about -7000 calories, so that the heat of formation of gaseous arsenic trifluoride is 191,300 calories. 

The Raman spectrum of arsenic trifluoride consists of four lines with the following frequencies aq (1)707, WaC1)34 (2) 644, and... 

Arsenic trifluoride reacts with bromine to form a crystalline substance iodine dissolves in the liquid yielding a purple-red solution the nature of these products has not been elucidated. 

Arsenic Pentafluoride, AsFs, may be prepared by the interaction of arsenic and fluorine in a platinum vessel,2 or by the action of bromine and antimony pentafluoride on arsenic trifluoride.3 The reagents should be dry, and if the reaction in the second case is carried out in a glass vessel, the apparatus should be in one piece and well dried. The bromine is added to the mixture of fluorides at - 20° C. and, after cooling in liquid air, the arsenic pentafluoride is obtained by heating on a water-bath at 55° C., the gas passing through a reflux condenser to a receiver surrounded by liquid air. The product contains bromine, which is removed by passing the gas over molten sulphur. 

---