in the figure , a schematic view of the process is given by way of example . a purification station 1 is provided with liquid halides 2 , through which a stream of gas or gas mixture to be purified enters at feed conduit 3 , leaving the purification station via outlet conduit 4 and is purified by adduct formation . the liquid halides 2 containing the adducts formed are continuously and cyclically introduced into a separate regeneration station 6 via outlet duct 5 . there , the adducts are decomposed , and the impurities set free can leave the regeneration station 6 by outlet tube 7 and can be directed to a trapping station , ( not shown ). the regenerated halides are reintroduced into the purification station 1 via conduit 8 and can again purify the streams of gas by adduct formation . the invention will now be explained more fully in a number of examples which are , however , only given by way of illustration and not of limitation . liquid hexachlorodisilane or hexachlorodisilane / silicon tetrachloride mixtures were supplied in a quantity of approximately 100 ml to a purification station designed as a temperature - controlled gas washer . the temperatures and mixture ratios established are shown in the table . a stream of hydrogen which contained various fractions of phosphorus hydride or phosphine ( ph 3 ) and which corresponded in its composition to the gas mixtures encountered in producing silicon after separating off the chlorosilanes and the hydrogen chloride present was passed through the gas washer . the ph 3 content of the gas stream was determined before and after the passage through the purification station with the aid of gaschromatographic methods . from this difference and the flow rate established in each case , it was possible to estimate the time necessary for reaching an adduct formation level of about 75 % of the maximum value determined in preliminary experiments . the values measured under these circumstances are set forth in the table . the liquid contained in the gas washer was now introduced via a supply line into the regeneration station . a receiving container was provided with a condenser and its temperature was controlled to the temperature specified in the table . at the same time , the corresponding quantity of regenerated liquid was returned to the purification station from the regeneration station so that the purification process could be continued in an analogous manner using this charge . both streams of liquid were passed in opposite directions through a counter flow heat exchanger so that they were able to mutually precool or preheat each other . table__________________________________________________________________________removal of phosphine from hydrogen containing phosphine ph . sub . 3 content ph . sub . 3 content temperature of temperature maximally before puri - after puri - regenerationhalide of purifica - bound ph . sub . 3 fication fication stationsupplied tion station (° c .) ( mole / l ) ( ppm ) ( ppm ) (° c . ) __________________________________________________________________________si . sub . 2 cl . sub . 6 20 1 . 3 × 10 . sup .- 3 5 , 000 & lt ; 1 7590 wt . % si . sub . 2 cl . sub . 6 - 20 4 . 0 × 10 . sup .- 3 10 , 000 & lt ; 1 6510 wt . % sicl . sub . 470 wt . % si . sub . 2 cl . sub . 6 - 40 5 . 7 × 10 . sup .- 3 5 , 000 & lt ; 1 6530 wt . % sicl . sub . 4__________________________________________________________________________ approximately 200 ml of liquid tin tetrachloride were introduced into a temperature - controlled gas washer and adjusted to a temperature of approximately 0 ° c . a gas stream of hydrogen containing approximately 4 . 7 % by volume of trichlorosilane and about 20 , 000 ppm of phosphorus hydride to be purified was bubbled through the liquid via a gas inlet tube with a frit plate . the residence time was approximately 1 sec in the liquid and approximately 10 sec in the gas phase of the purification station . the gas stream was then passed through a dry - ice condenser ( condensing temperature approximately - 78 ° c . ), and also an absorber charged with sodium hydroxide pellets and an absorber charged with phosphorus pentoxide . the gas stream was then supplied to a gas chromatograph to detect the phosphorus hydride left behind . it was no longer possible to detect any phosphorus hydride with the gas chromatograph , i . e . the content was below the limit of detection of approximately 1 ppm . in the purification station , a solid , yellowish - orange adduct began to form which dispersed itself in the liquid phase . this adduct formation was continued until it was possible to detect an increase in the phosphorus hydride level in the gas chromatograph . the supply of the gas to be purified was now shut off and instead , a gentle stream of nitrogen was blown in which was then passed through a washer charged with sodium hypochlorite solution . on raising the temperature to about 90 ° c . in the purification station , now functioning as a regeneration station , the yellowish - orange precipitate that had formed gradually began to disappear and the phosphorus hydride thus liberated was discharged with the gas stream and eliminated in the downstream trapping station . after it was no longer possible to detect any yellowish - orange color in the liquid , the stream of nitrogen was shut off , the temperature was reduced to 0 ° c . and the gas stream to be purified was reintroduced . after a short time the adduct formation , which was recognizable from the formation of an orange - red precipitate , set in ; the gas stream monitored in the gas chromatograph was free of phosphorus hydride . it was possible to repeat this cycle several times without difficulties . a quantity of 200 ml of titanium tetrachloride was introduced as the halide into the arrangement described in example 2 under otherwise identical conditions . the gas stream to be purified was hydrogen containing a fraction of 400 ppm of phosphorus hydride . a solid , reddish - brown adduct was formed in the purification station , while it was not possible to detect any phosphorus hydride in the resulting gas stream by gas chromatography . both the purification step ( temperature : 0 ° c .) and the regeneration step ( temperature : 80 ° c .) were carried out analogously to the process specified in example 2 and it was possible to repeat them several times without difficulty . liquid trichlorosilane , to which approximately 5 % by weight of a thermally untreated liquid high - boiler mixture composed mainly of silicon chlorides with 2 - 4 atoms of silicon in the molecule had been added , was introduced into a distillation column as the substance to be purified . the mixture was contaminated by passing a stream of hydrogen enriched with 0 . 5 % by volume of phosphorus hydride through it for 20 minutes . in the subsequent distillation , the trichlorosilane was removed at the column head and was introduced , with the addition of hydrogen , into a test deposition installation where it was decomposed to deposit elementary silicon on a thin silicon ingot . the silicon obtained in this process had a specific resistance of 30 ohm · cm ( n - type ) which corresponds to a phosphorus content of approximately 1 . 5 × 10 14 atoms of phosphorus / cm 3 . after the main fraction of trichlorosilane had been distilled off from the column , 3 % by weight of thermally unpretreated high boiler was added to the bottom . the temperature in the bottom was then raised to approximately 85 ° c . to regenerate the high boiler and the phosphorus hydride liberated was removed from the column by means of a stream of nitrogen . the column was then again charged with trichlorosilane through which a stream of hydrogen enriched with 0 . 5 % by volume of phosphorus hydride had previously been passed at the same flow rate as in the preliminary experiment . the high - boiler fraction was again approximately 5 % by weight . the trichlorosilane was removed in an analogous manner in the subsequent distillation and supplied for a test deposition . the silicon obtained had a specific resistance of 80 ohm · cm ( n - type ), corresponding to a phosphorus content of 5 . 2 × 10 13 atoms of phosphorus / cm 3 . this is equivalent to a reduction in the degree of contamination by about 65 %. while several embodiments and / or examples of the present invention have been described , it will be obvious that many changes and modifications may be made thereonto without departing from the spirit and scope of the invention .