ELISHA MITCHELL SCIENTIFIC SOCIETY. 79 



AX EXAMINATION OF THE CHLORIDES OF 

 ZIRCONIUM. 



BY F. P. VENABLE. 



A chloride of zirconium of definite composition would 

 prove a v^aluable compound for determining* the atomic 

 Aveig'ht of the element. There are several difficulties 

 in the way of securing- such a result: 



1. The tendency to form basic chlorides. 



2. The ease with which h3^drochloric acid is lost 

 throug-h the action of heat and of dehydrating- ag-ents. 



3. The presence of free hvdrochloric acid. 



4. The deliquescent nature of the chlorides. 



It is particularly desirable that the conditions under 

 which a definite chloride can be formed should be dis- 

 covered, as zirconium seems to yield no very satisfac- 

 tor}^ compounds for the determination of the atomic 

 weig-ht. There have been many efforts at finding- out 

 these exact conditions. 



Most text-books state that anhydrous, pure zirco- 

 nium tetra-chloride can be prepared by passing- drv chlo- 

 rine over a mixture of charcoal and zirconia heated to a 

 hig-h temperature. Hermann used this sublimed zirco- 

 nium chloride for the determination of the atomic 

 weig-ht. As Clarke says, however, little confidence 

 can be placed in his results. Bailey'"' has recorded that 

 even with g-reat care to avoid the presence of moisture, 

 he was unable to prevent the formation of ox3xhlorides. 

 He also says that in no case was it found possible to 

 prepare the chloride free from iron and silica. The 



*Chem. News. EX.. 17. 



