IRON, COBALT, AND NICKEL 867 



Nickel alloys possess qualities which render them valuable for 

 technical purposes, the alloy of nickel with iron being particularly 

 remarkable. This alloy is met With in nature as meteoric iron. The, 

 Pallasoffsky mass of meteoric iron, preserved in the St. Petersburg 

 Academy, fell in Siberia in the last century ; it weighs about 15 cwt. 

 and contains 88 p.c. of iron and about 10 p.c. of nickel, with a 

 small admixture of other metals. In the arts German silver is most 

 extensively used ; it is an alloy containing nickel, copper, and zinc in 

 various proportions. It generally consists of about 50 parts of copper, 

 25 parts of zinc, and 25 parts of nickel. This alloy is characterised by 

 its white colour resembling that of silver, and, like this latter metal, it 

 does not rust, and therefore furnishes an excellent substitute for silver 

 in the majority of cases where it is used. Alloys which contain silver 

 in addition to nickel show the properties of silver to a still greater 

 extent. Alloys of nickel are used for currency, and if rich deposits of 

 nickel are discovered a wide field of application lies before it, not only 

 in a pure state (because it is a beautiful metal and does not rust) but 

 also for use in alloys. Steel vessels (pressed or forged out of sheet 

 steel) covered with nickel have such practical merits that their manu- 

 facture, which has not long commenced, will most probably be rapidly 

 developed, whilst nickel steel, which exceeds ordinary steel in its 

 tenacity, has already proved its excellent qualities for many purposes 

 (for instance, for armour plate). 



Until 1890 no compound of cobalt or nickel was known of sufficient 

 volatility to determine the molecular weights of the compounds of these 

 metals ; but in 1890 Mr, L. Mond, in conducting (together with Langer 

 and Quincke) his researches on the action of nickel upon carbonic oxide 

 (Chapter IX., Note 24 bis), observed that nickel gradually volatilises in 

 a stream of carbonic oxide ; this only takes place at low temperatures, 

 and is seen by the coloration of the flame of the carbonic oxide. This 

 observation led to the discovery of a remarkable volatile compound of 

 nickel and carbonic 'oxide, having as molecular composition Ni(CO) 4 , 38 



it is obtained by means of iodine (probably through H10), and its great resemblance 

 to Mn0 2 , leads rather, to the supposition that CoD 3 is a very feeble saline oxide. The 

 form Co0 2 is repeated in the cobaltic compounds (Note 85), and the existence of CoO<j 

 should have long ago been recognised upon this basis. 



58 This compound is known as nickel tetra-carbonyl. It appears to me yet premature 

 to judge of the structure of such an extraordinary compound as Ni(CO) 4 . , It has long 

 been known that potassium combines with CO forming K n (CO) n (Chapter IX., Note 81), 

 but this substance is apparently saline and non-volatile, and has as little in common 

 with Ni(CO) 4 as N^H has with SbH 3 . However, Berthelot observed that when NiC 4 O 4 

 is kept in air, it oxidises and gives a colourless compound, Ni 3 C 3 O 5 ,10H 8 0, having 

 apparently saline properties. We may add that Schutzenberger, on reducing NiClj by 

 heating it in a current of hydrogen, observed that a nickel compound partially volatilises 

 with the HC1 and gives metallic nickel when heated again. The platinum compound, 

 *E 



