90 P. T. CL EVE, 



G. Ammoniacal compounds of Osmium. 



Mr Frémy l ) observed that sal-ammoniac with the osmite of potassium gives a 

 yellow crystalline precipitate, the coraposition of which he expresses by the formula 

 2NH 4 Cl + 2NH 2 . Os £ . Mrss Gentii and Gibbs 2 ) found that this compound with tetra- 

 chloride of platinum gives a double chloride, and that its chlorine can be exchanged 

 by double decomposition, for which reason they assign to it the formula Os . 4NH 3 . Cl.. 

 + 2H 2 0. This view is confirmed by Mr Claus 3 ), and the compound may be regarded 

 as the chloride of osmiodiammine. 



Tetra-atomic osmium also seems to unite with ammonia. Chloro-osmiate of po- 

 tassium mixed with ammonia, yields a brown compound (the »osmiumsesquioxidul- 

 amoniak» of Berzelius). Its formula is Os . 2NH 3 . 0., + PLO according to Claus 3 ), and 

 with hydrochloric acid it gives a chloride, probably of the formula Os . 2NH 3 . Cl 4 

 +xH 2 0, which has a great tendency to form basic compounds. 



The interesting compound found by Fritsciie and Stkuve *) the osman-osmic acid, 

 which is formed by the action of ammonia upon hyperosmic acicl is not a true com- 

 pound of ammonia. Its formula is IT 2 • 2 . (Os_> N 2 3 ) and may possibly be written 

 atomically in the following manner: 



2N.(Os— Os)0 8 .20H 



Nitrogen seems to be direetly united to osmium, as in some compounds of mer- 

 cery called mcrcuri-nitrilo-compounds in the following. Still our knowledge of this 

 interesting acid is very small, and on this account the formula is rather doubtful. 



H. Ammoniacal compounds of silver. 5 ) 



The salts of silver have a great affinity with ammonia, but the ammoniacal com- 

 pounds of silver are easily destroyed. 



All the known ammoniacal compound of silver appear to belong to three diffe- 

 rent radicles. 



Ag t .6NH,j Ag,.4NH 3 ; A gi . 2NH 3 . 



With ammonia the iodide of silver seems to give a compound Ag.. . NH 3 . I 2 6 ), 

 which would then belong to a fourth radicle Ag 2 NH 2 , but this iodide very easily löses 

 its ammonia and its composition is therefore very doubtful. There can scarcely be any 

 uncertainty about the atomical formulas for the two rirst radicles. They are certainly 



i f 3NH 3 i i- • » |2NH, rm , . , .. . 



argent-triammme Agyj ; > XIL and argent-aiammine Ag 2 \2NH. i " e third radicle may be 



• 1 A f NH 3 A J 2NH 3> 1 , T ■ • i 1 ^XTTT 



either Agvj NII or Ag 2 | or else the compounds containmg Ag.. and 2rv'rl : , are do- 



x ) Frémy Ann. de Chera. et de Phys. (3) 12. 521. 



'-) Genth and Gibbs Sillim., Am. Journ. (2) 25 p. 248. 



:! ) Claus Bullet. de l'académ. Imp. des sciences de St Petersbourg T. A T I 1863. p. 17G. 1858. 



4 ) Fritsche and Struve Journ. f. Pr. Cli., 11, 97. 



•') Silver is generally supposed to be a monatomic element, but in my oppiuion it is more correct to regard 



it as a two-atomic raetal, wberefore I have followed the exemple of Wislicenus (Berichte d. Deutsch. 



Chem. Gesellsh. zu Berlin 1871. N:o 1. j>. G3), in designating the chloride of silver: Ag 2 CU (Ag=108). 

 8 ) Rammelsbeug, Pogg. Ann. 48 p. 169. 1839. 



