ATOMIC WEIGHTS 451 



RHODIUM. 



Berzelius ' determined the atomic weight of this metal by tlie analvsis 

 of sodium and potassinm rhodiochlorides, NaoEhClg and KoEhCl.,. The 

 latter salt was dried by heating in chlorine. The compounds were analyzed 

 by reduction in hydrogen, after the usual manner. Eeduced to per- 

 centages, the analyses are as follows : 



In Na.RhCk. 



Rh. SNaCl SCI 



26.959 45.853 27.189 



27.229 45.301 27.470 



27.616 



Mean, 27.094 Mean, 45.577 Mean, 27.425 



In KMhCl,. 



Rh. 2KCI. SCI. 



28.989 41.450 29.561 



From analyses of the sodium salt we get the following values for Eh : 



From per cent, of metal Rh = 104.72 



From per cent, of NaCl " = 103.08 



From per cent, of 3C1 " = 106.10 



From ratio between 3C1 and Rh " = 104.85 



From ratio between 3NaCl and Rh " =104.27 



These are discordant figures; but the last one fits in fairly well with 

 the values calculated from the potassium compound, which are as follows: 



From per cent, of metal Rh = 104.30 



From per cent, of KCl " = 104.26 



From per cent, of CI " = 104.36 



From Rh:5Cl ratio " = 104.32 



From Rh:2KCl ratio " =104.29 



Mean Rh = 104.37 



The determinations by Jorgensen ' seem to have been preliminary, but 

 are good so far as they go. Ehodium pentamine chloride, Eh(N'H3)5Cl3, 

 was ignited in hydrogen, and the residual metal was cooled in an at- 

 mosphere of carbon dioxide. The data are as follows: 



Chloride. Rhodium. Per cent. Rh. 



3.5180 1.2310 34.991 



2.1507 .7517 34.951 



.9091 .3182 35.002 



1.9889 .6960 34.994 



Mean, 34.984, ± .0076 

 Hence Eh = 103.0G. 



1 Poggend. Annalen. 13, 435. 182S. 



= Journ. prakt. Chem. (2), 27, 486. 1S83. 



