556 Litellige7tce and Miscellaneous Articles. 



intensity of this colour increases ; the liquor soon becomes opake, and 

 iodine is precipitated in a pulverulent state. If the operation be 

 stopped when this deposit ceases to be formed, all the iodine is 

 separated, no sensible quantity of chloride of iodine is formed, and 

 the liquor contains chloride of potassium ; if the operation be con- 

 tinued, the iodine redissolves, and the liquor assumes a fine golden 

 colour. Sometimes a little chloriodate of potash precipitates ; this 

 happens especially if the iodide is not perfectly neutral, and it is easy 

 to account for it. When all the iodine is dissolved, it is proper to 

 continue the disengagement of the chlorine : fine golden coloured 

 needles soon appear in the liquor, and the quantity increases as the 

 saturation with the chlorine proceeds. When a saturated solution 

 of the iodide is employed, the liquor submitted to the action of the 

 chlorine, is eventually converted into a yellow needle-formed mass 

 of a beautiful appearance ; in order that the reaction may be per- 

 fect, it is well to heat the liquor slightly, that the tube which con- 

 veys the chlorine may not be obstructed. 



When the chlorine ceases to be sensibly absorbed, the operation 

 is to be stopped, and then, in order to obtain finer crystals, the bottle 

 may be immersed in water heated from 105° to 125° Fahr. ; by this the 

 crystals are redissolved, and recrystallization takes place slowly. The 

 crystals are similar to those obtained by the action of hydrochloric 

 acid on iodate of potash ; but the process now described is very con- 

 venient for obtaining considerable quantities of this salt. 



It appears to be composed of 



One equivalent of bichloride of iodine SS^ 



One . „ chloride of potassium 76 — 310 



and when it is heated the perchloride of iodine is expelled and the 

 chloride of potassium remains. 



The iodides of ammonium and of magnesium furnished results 

 corresponding to the above ; but the iodides of sodium and barium 

 did not yield chlorosalts. Biniodide of mercury was treated in the 

 same manner, and a fine golden-coloured solution was obtained which 

 did not yield crystals. 



It will be observed that chlorine acts upon the iodides as it does 

 upon the sulphurets ; but the chloride of sulphur combines readily 

 with acid chlorides, whilst the chloride of iodine combines better 

 with the alkaline chlorides. 



It ought to be observed, that the salt obtained by the process 

 above described, if it be required very pure, ought to be very quickly 

 separated from the watery liquid, in which it is formed ; for if the 

 chloride of iodine is decomposed in iodic and hydrochloric acids, 

 which may happen, as is well known, with great readiness, it may 

 occur that the less solubility of the iodate of potash may determine 

 the decomposition of the alkaline chloride, and the precipitation of a 

 little iodate, for there does exist sufficient hydrochloric acid to pre- 

 vent the formation of the iodate which occurs rapidly ; the salt there- 

 fore intended for analysis ought to be separated as soon as it is 

 formed. 



