46 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 13, No. 3 
Author’s Abstract: Pure osmium was prepared by making use of the 
following reactions. When OsO, and constant boiling HCl, in the presence 
of a small amount of C,.H;OH, were heated in a reflux apparatus for about 
three hours, the OsO, was converted to chlorosmic acid, H:OsCls. After 
evaporation to a syrup and dilution with H,O, the osmium was precipitated 
as the brick red (NH4)sOsCl¢, with NH,Cl. The (NH4)2.OsCls was reduced 
to metal in H». The H: was completely removed by nitrogen while the 
metal was still red hot. On cooling, gray osmium sponge resulted which was 
not attacked by the oxygen of the air. 
The reagents employed in the above reactions were volatile ones which 
allowed of easy purification. The purification cycle could be repeated con- 
veniently. Spectroscopically pure osmium was thus obtained. 
The reaction between OsO, and 20 per cent HBr took place without the 
addition of C.H;OH, and was complete in about one-half hour. Bromosmic 
acid, HsOsBre, was obtained in this case from which NH,Br precipitated the 
black (NH,4)2OsBrg. 
Two sources of osmium were used for the preparation of the salts for 
analysis. (NH4)2OsCl, was made from osmium obtained from Baker and 
Company. (NH,),OsBrs was made from osmium obtained in the working 
up of some osmiridium residues recovered during refining of Russian crude 
platinum. 
The results of the analyses were as follows: 
BAKER AND Company (NH,)2OsCle, Series I 
WEIGHT OF 
WEIGHT OF ATOMIC 
1ST ES eek OSMIUM IN VACUO ee WEIGHT 
grams grams per cent 
1 1.46116 0.63688 43 .587 
2 2.80587 1.22226 43 .560 
3 2.32007 1.01021 43 .542 
4 1.93756 0.84390 43 .555 
5 2.92857 1.27597 43 .569 
43 .563 192 .074 
(NH,)20sCls:Os = 100:43.563 
Russtan (NH,)2:OsBre, Serres II anv III 
WEIGHT OF 
exrenmumsr | NHQOsBre | gg AORN | onto om 
IN VACUO , 
grams grams per cent 
1 4.17909 1.13522 27.164 
1 1.72778 0.46909 27.150 
2 0.98661 0.26783 27.146 
27.153 192.172 
(NH,4)2OsBr.5:Os = 1002 
Average of eight experiments 
Os = 192.1 
i si 
