114 Compounds of Ammonia with Selenium Dioxide. [Apr. 19, 



which 0*4153 gram was taken, yielded 1*1206 gram of the double 

 chloride, equivalent to 20*69 per cent, of ammonia. In a third esti- 

 mation, 0*3835 gram was evaporated down with platinum chloride, 

 but the double chloride obtained, 1*0237 gram, showed a rather 

 smaller percentage of ammonia, namely, 20*52. The mean of the 

 first two results, 20*64, is equal to 87*94 per cent, of the total 

 ammonia, and indicates that in addition to the basic nitrogen, about 

 three-fourths of the nitrogen contained in the radical of the salt is 

 precipitated by platinum chloride. 



Preparation of Acid Ammonium Selenosamate. 



A solution of the neutral salt in absolute alcohol was boiled down 

 on the water-bath until crystals were deposited. The liquid portion 

 was then drained off, and the crystals washed with alcohol, and dried 

 in a vacuum. On examination, they proved to consist of an acid 

 salt. It was also found that exposure of the neutral salt in a vacuum 

 over sulphuric acid for thirty hours was sufficient to convert it into 

 the same acid compound. A portion of the salt obtained in the 

 latter way was submitted to analysis. For estimation of the selenium, 

 0*2 gram was dissolved in water, saturated with chlorine, and pre- 

 cipitated with barium chloride. The resulting barium selenate 

 weighed 0*409 gram, equivalent to a percentage of 81*11 of selenium 

 dioxide. In a second estimation, 0*4268 gram yielded 0*8761 gram of 

 barium selenate, equivalent to 81*42 per cent, of selenium dioxide. 

 Kjeldahl's process was found to be unsuitable in this case for esti- 

 mating the ammonia, the amount yielded by it being much too low, 

 although a very high temperature was maintained for a considerable 

 time. Combustion with soda-lime also gave insufficient results, owing 

 to a portion of the substance being decomposed by the heat employed, 

 with evolution of nitrogen. Somewhat better results were obtained 

 by Dumas' process : 0"4035 gram yielded 49*9 c.c. of nitrogen at 12° 

 and 771*6 mm., equivalent to a percentage of 18*09 of ammonia. An 

 estimation of the selenium in the dried crystals was also made : 

 0*1523 gram yielded 0*3134 gram of barium selenace, equivalent to 

 81*62 per cent, of selenium dioxide. The results thus obtained agree 

 with the formula 3^H 3 ,2Se0 2 = ^H 4 ,H,(Se0 3 NH 2 ) 2 . 



Prepared in vacuum. Crystallised 



( A ^ from alcohol. Calculated. 



1. 2. 3. 4. 



Se0 2 81*42 .... 81*11 .... 81*62 .... 81*30 



KH 3 18*09 .... — .... — .... 18*70 



The salt thus obtained is deliquescent, and easily soluble in alcohol, 

 from which it separates in large prisms. 2*0270 grams of saturated 

 solution left a residue weighing 0*1191 gram, showing a solubility of 



