[ 433 ] 



LXIX. Kole upon tfie Comhinaimi. of Sulphur uiih Chrome^ 

 and 7ipnn a new Process for obtaining the Oxide of that Me- 

 tal. £j/ J, L. Lassaigne *. 



An making latelv «ome experiments upon the oxide of clirome, 

 I endeavoured without success to decompo'^e it by sulphur, in 

 order to obtain a combination of metal with this combustible 

 body, both by melting tlie mixture of the two bodies in a cruci- 

 ble, and by making the vapour of the sulphur pass over the oxide 

 of chrome heated white red in a porcelain tube. I despaired of 

 succeeding; when, reflecting upon the property which the greater 

 part of the metallic cliloruiets possess of being decomposed by 

 sulphur and converted into chlorurets, the idea occurred to me 

 of submitting the muriate of chrome in a dried state (which I 

 consider as a chlorurct) to the action of sulphur. 



After having prepared some chloruret from pure chrome, by 

 boiling together chromic acid and hydrochloric acid in excess, 

 1 evaporated it to dryness in a porcelain vessel : in this state it 

 was of a hortensia-rose colour in the form of a mass very slightly 

 puffed up : being reduced to powder and mixed with five times 

 its weight of flour of sulphur, it was put into a bent tube of glass 

 and brought gradually to a white heat. 



At the commencement of this operation a little hydrosulphuric 

 gas became disengaged ; afterwards some hydrochloric gas ; then 

 the excess of sulphur sublimated with a small quantity of chlo- 

 ruret of rose chrome ; lastly, very thick white vapours of a dis- 

 agreeable smart odour, which I recognised to be the chloruret of 

 sulphur, were emitted during the rest of the calcination. 



The lower part of the tube inclosed a blackish gray matter, 

 which was very friable, the slightest shock reducing it easily to 

 powder, and several experiments convinced me that it was a 

 true sulphuret of chrome. 



Proper lies of this Sulphuret. 



1. It is blackish gray, unctuous to the touch ; it makes on 

 any hard substance a blackish mark as brilliant as plumbago. 



2. Heated to a wax red in a small crucible of platina, it 

 burns like pyrophorus, exhaling a smart odour of sulphurous 

 acid, and produces an oxide of chrome of a deep green. 



.'3. Nitric acid has no sensible effect on this sulphuret even with 

 the assistance of heat, but aqua regia converts it into sulphuric 

 acid and into chloruret of green chrome. 



Being desirous of ascertaining the proportion in which these 



• Frotij the Annates ilti Cklmie ci de Pk\js\q\ie, for July 1820. 

 Vol. 5G. No. 272. Dec. 1820. 3 I two 



