RHODIUM. 465 



was ill all probability formed by the change of 

 the integrant particle of muriate of soda into 

 chloride of sodium. 



5. The preceding analysis, when compared 

 with the preliminary experiment, leaves no 

 doubt that the weight of an atom of rhodium is Atom of 



. - , _ rhodium. 



5%5, and that the yellow oxide is a compound of 

 1 atom rhodium and 2 atoms oxygen. 



This oxide of rhodium is described by Ber- oxides of 

 zelius as brown ; but when obtained by precipi- r 

 tation from the soda-muriate of rhodium, it is 

 always yellow. When exposed to heat it be- 

 comes slowly brown, and at last black. During 

 this change of colour, I could detect no escape 

 of moisture, to induce me to suppose that the 

 yellow coloured powder is a hydrate, and the 

 brown the anhydrous oxide. Whether the brown 

 oxide be the same, or different from the yellow, 

 I have not ascertained ; most probably it is a 

 mixture of the yellow and the black oxides. 

 The black oxide is undoubtedly the protoxide of 

 rhodium, and a compound of 1 atom rhodium 

 and 1 atom oxygen ; so that its atomic weight is 

 6-5. 



If the brown powder should appear, upon far- 

 ther examination^ to be a peculiar oxide, it is 

 obvious that it must be a compound of 1 atom 

 rhodium and li atom oxygen ; and that its ato- 

 mic weight must be 7 I did not succeed in my 

 attempts to dissolve it in acids ; but this insolu- 



Vot. I. G g 



