672 Mr. Ludwig Mond [June 3, 



heated to incandescence in the flame. If we pass the gas through a 

 freezing mixture, you will observe that a colourless liquid is con- 

 densed, of which I have a larger quantity standing in this tube. In 

 passing the gas issuing from our tube through a glass tube heated to 

 about 200° C, we obtain a metallic mirror of pure nickel, because at 

 this temperature the nickel carbonyl is again completely resolved 

 into its components, nickel and carbonic oxide. We will by-and-by 

 show you that this mirror consists of pure nickel. This liquid is 

 pure nickel carbonyl, and has the formula Ni(C0)4. It has a 

 specific gravity at ordinary temperature of 1*3185, and boils under 

 atmospheric pressure at the low temperature of 43° C. 



It has a very high vapour tension at ordinary temperature and 

 possesses a very high rate of expansion. If cooled to — 25° C. it 

 solidifies, forming needle-shaped crystals. A mixture of the vapour 

 with air explodes readily, sometimes at ordinary temperature, but 

 without violence, as we will show you. The liquid itself in the pure 

 state does not explode, but decomposes into its constitutents when 

 heated sufficiently. The vapour of nickel carbonyl possesses a 

 characteristic odour and is poisonous, but not more so than carbonic 

 oxide gas. Prof. McKeudrick has studied the physiological action 

 of this liquid, and has found that, when injected subcutaneously in 

 extremely small doses in rabbits, it produces an extraordinary reduc- 

 tion of temperature, in some cases as much as 12°. 



The liquid can be completely distilled without decomposition, 

 but from its solution in liquids of a higher boiling point it cannot be 

 obtained by rectification. On heating such a solution the compound 

 is decomposed, nickel being separated in the liquid, while carbonic 

 oxide gas escapes. I will try to demonstrate this by an experiment. 



We have here a solution of the substance in heavy petroleum oil, 

 which you will, in a few minutes, see turns completely black on heat- 

 ing by the separation of nickel, while a gas escapes which is pure 

 carbonic oxide. 



In a similar way, when the nickel carbonyl is attacked by oxidising 

 agents, such as nitric acid, chlorine, or bromine, it is readily broken 

 up, nickel salts being formed, and carbonic oxide being liberated. 

 Sulphur acts in a similar way. Metals, even potassium, alkalies, and 

 acids, which have no oxidizing power, will not act upon the liquid at 

 all, nor do the salts of other metals react upon it. The substance 

 behaves therefore, chemically, in an entirely diflerent manner from 

 potassium carbonyl, and does not lead, as the other docs, by easy 

 methods to complicated organic compounds. It does not show any 

 one of the reactions which are so characteristic for organic bodies 

 containing jarbonyl, such as the Ketones and Quinones ; and we have 

 not been able, in spite of very numerous experiments, either to substi- 

 tute the carbonic oxide in this compound by other bivalent groups, or 

 to introduce the carbonic oxide by means of this compound into 

 organic substances. 



By exposing the liquid to atmospheric air a precipitate of carbo- 



