SIK WILLIAM CEOOKES ON SCANDIUM. 367 



For analysis the hydrate, dried to a constant weight, was dissolved in water and 

 the gold precipitated by the addition of metallic magnesium, the liquid being well 

 boiled. The filtrate from the gold was mixed with an excess of ammonium chloride, 

 ammonia was added, and the whole boiled. The scandia, which came down free from 

 magnesia, was filtered, washed, dried, and ignited. 



Analysis. 



19'302 gr. treated as described yielded 6'341 gr. of gold and 3'174 gr. of scandia, 



= 2 '05 54 gr. of scandium. 



Theory. Experiment. 



10-65 



32-85 



56-21 56-50 



120273 100-00 100-00 



ANHYDROUS SCANDIUM AUROCHLORIDE, 

 3ScCl s ,2AuCl s . 



The weight of the anhydrous salt obtained by continued drying of 26 "7 17 gr. of the 

 21-hydrate at 100 was 19"695. This amount of anhydrous scandium aurochloride 

 gave 7'361 gr. of gold and 3'862 gr. of scandia, = 2'5009 gr. of scandium. 



Theory. Experiment. 



12-70 

 37-37 

 49-93 



1058-60 100-00 100-00 



SCANDIUM PLATING-CYANIDE, 



Sc 2 [Pt(CN) 4 ] 3 +2lH 2 O. 



Scandium platinocyanide is formed by the metathesis in the cold of scandium 

 sulphate and barium platinocyanide. 



The barium sulphate filtered off, the clear liquid is evaporated at a moderate 

 temperature. Scandium platinocyanide crystallises out in large monoclinic prisms on 

 a rhombic base, the angles of which are 81 20' and 98 40'. The crystals frequently 

 group themselves in rosettes. They are dichroic, crimson by transmitted light, and 

 a rich metallic green by reflected light. The reflected and transmitted rays are 



