20 SIR WILLIAM CROOKES ON SCANDIUM. 



Scandium carbonate holds carbonic acid very weakly, and concordant analyses are 

 not easy to get. Drying at 100 drives off water and some of the carbon dioxide, 

 leaving a basic carbonate. When freshly precipitated and dried in a current of air 

 at the ordinary temperature, the following formula best agrees with the figures 



obtained : 



Sc 2 (C0 3 ) 3 ,12H 2 0. 



At a temperature of 100 this salt loses carbon dioxide and water, and becomes a 

 basic salt of uncertain composition. 



Strong ignition drives off all water and carbon dioxide, leaving Sc 2 3 . 



HYDRATED SCANDIUM CHLORIDE, 



Sc 2 CU2H 2 O. 



The hydrated salt is prepared by dissolving the earth in hydrochloric acid and 

 evaporating on a water-bath. It crystallises from a strong solution as a felt-like mass 

 of fine white needles. The crystals should be pressed many times between filter-paper 

 frequently renewed, and put to dry for a few hours in a desiccator over sulphuric 

 acid. They are somewhat deliquescent, but not so much so as the nitrate, and are 

 readily soluble in alcohol. They have the following composition : 



Sc 2 01 6 ,12H 2 = Sc 2 3 ,GHCl,9H 2 0. 



Analysis. 



(1) G'087 grs. of the pressed chloride left on ignition T620 grs. of scandia. 

 ("2} 5'9GO grs. of the pressed chloride lost T83G grs. after remaining in the water- 

 oven at 100 for six hours. 



Theory. Experiment. 



Sc 2 3 .... 

 GHC1 .... 

 9H 2 O .... 



517-092 100-00 100-00 



When heated for six hours to a temperature of 100, the 9 molecules of water go 

 off, leaving a clear, colourless, and oily liquid, which on cooling solidifies to a white 

 crystalline mass of the composition . 



Sc a Cl 6 ,3H 3 = Sc 2 3 ,6HCl. 



When this salt is gradually heated to redness it gives off 6 molecules of hydrochloric 

 acid with much intumescence, leaving a bulky residue of scandia. 



