1811.] On Palladium and Rhodium. 2fl 



Article VII. 

 Memoir on Palladium and Rhodium. By M. Vauquelin. 



(Concluded from p. 222.) 



IV. 



Propei lies of the neutral Ammonio-muriate of Palladium, or of 

 Sulmuriate of Palladium. 



This salt has a very fine rose colour. In this point of vievr 

 palladium is better entitled to the name of rhodium than the metal 

 which bears it. When we examine this salt we find that it is 

 composed of very delicate, flexible, and brilliant needles, which 

 form a spongy mass, very soft to the touch. 



Reduction. — Twenty grammes (308-88 grains) of the dry salt 

 heated strongly in the heat of a forge in an earthen crucible fur- 

 nished eight grammes ( 1 L2J4- grains), or 40 per cent, of a metal 

 having the colour of unpolished silver. Its parts were united 

 together, but incompletely melted. 



This metal might be hammered or passed between rollers without 

 breaking. 



To see better what takes place during the decomposition of this 

 salt of palladium by heat, I exposed it to the blow-pipe. It melted, 

 diminished much in volume, and exhaled vapours of sal ammoniac 

 and oxymuriatic acid. It is the melting and the diminution of 

 volume of this salt which, bringing the particles of metal "nearer 

 each other, renders them susceptible of being hammered and rolled 

 out into plates. 



Solubililij. — The red salt of palladium is very little soluble in 

 water. It merely gives it by long contact a slight tint of yellow. 

 It is but litlle soluble in diluted muriatic acid, when not assisted by 

 heat ; but at a boiling temperature the acid dissolves it in consider- 

 able quantity. The solution is of a yellowish brown colour. When 

 the excess Of acid of the solution is satuiated with ammonia, the 

 salt precipitates with its rose colour, and all its other properties. If 

 an excess of alkali be added, the liquid assumes a slightly yellowish 

 colour. 



If instead of ammonia, potash be employed to saturate the excess 

 of muriatic acid, the salt precipitates in vellow flocks ; but if we 

 -Kid ammonia, they become red, showing that they again unite with 

 ItnmoaUl and form the triple salt. 



V. 



Some Properties of Palladium. 



Thij metal bai tome resemblance to platinum in its colour, 

 malleability, hardness, and fusibility. 



I !k/ heat of our furnace* does not melt it completely. I have 



