456 M. Buff and Wohler on new Silicon Compounds. 



of this remarkable body without the aid of the galvanic current, 

 have described more fully* the series of new silicon compounds, 

 of which a short notice has already appeared in this Journal. 



Hydrochlorate of Protochloride of Silicon, Si^CF + 2HCl. — 

 This is prepared by passing dry hydrochloric acid gas over cry- 

 stallized silicon heated in a glass tube just below redness. To 

 the anterior part of the tube a U-shaped tube-receiver is attached, 

 which is placed in a freezing mixture of ice and salt, and with 

 which is connected a gas-delivery tube dipping in ice-cold 

 water. The tube must not be heated too high, otherwise ordi- 

 nai'y chloride of silicon would be formed. The hydrochloric acid 

 is readily decomposed, and inflammable siliciuretted hydrogen 

 continually bubbles through the condensing water ; at the same 

 time some uncondensed protochloride is carried away in the 

 sti'eam of gas, which, decomposing with the water, forms a new 

 oxide of silicon. In order to prevent the latter from decompo- 

 sing, it is necessary to keep down the temperature of the water. 



After the operation is concluded, the protochloride is found in 

 the U-tube. It is turbid, and contains several substances. On 

 distilling it, it begins to boil at 28^ — 30° C, and the tempera- 

 ture gradually rises to 60°, the greater part passing over at 40° 

 — 43° C. This is the new substance. 



The protochloride of silicon is a colourless mobile liquid, of an 

 irritating odour, fuming strongly in the air, and covering every- 

 thing with a white incrustation. It boils at 42° C, and its 

 specific gravity is 1*65. It does not conduct the galvanic cur- 

 rent. Its vapour is as inflammable as that of sether, and it 

 burns with a feeble greenish flame, emitting vapours of silica and 

 hydrochloric acid. When mixed with excess of oxygen in a eudio- 

 meter, and the electric spark passed through the mixture, it ex- 

 plodes with great violence, covering the inside of the tube with 

 silica. The residual gas fumes strongly, and contains chloride 

 of silicon and hydrochloi'ic acid. When its vapour is passed 

 through a red-hot tube, it is decomposed into ordinai'y chloride 

 of silicon and hydrochloric acid. With water it decomposes in- 

 stantaneously into hydrochloric acid and into a new oxide of 

 silicon, very difierent in appearance from ordinary silicon. The 

 gaseous protochloride is also readily absorbed by alcohol and 

 aether without separation of the oxide. 



The numbers obtained in the analyses show that the substance 

 contained some ordinary chloride, from which indeed it is ex- 

 ceedingly difficult to free the protochloride, as their boiling- 

 points only diff"er by 17 degrees. Bufi^ and Wohler supposed at 

 first that the formula of the body was Si^ CP, as the two equiva- 

 lents of hydrogen, which only amount to 0'9 per cent., scarcely 

 * Liebig's Annalen, October 1857. 



