THE CHEMICAL BEHAVIOR OF ZIRCONIUM 

 By F. p. Venable 



Any discussion of the chemical relations and behavior of an ele- 

 ment forms necessarily an unfinished chapter in the present state of 

 knowledge. This is particularly true of zirconium, which has been 

 so imperfectly studied, where comphcations are many and their 

 unraveling presents unusual difficulties. It is only by the apphca- 

 tion of the most modern chemical and physical methods that a solu- 

 tion can be hoped for; hence it is not strange that many of the earlier 

 observations were faulty and misleading, and that only partial knowl- 

 edge has been attained as yet. 



Since there is no positive evidence that the valence of zirconium 

 is ever other than four, there is at least a helpful simplicity in this 

 regard. In the ionization of its compounds two varieties of ions are 

 definitely known, namely, the quadrivalent zirconium Zr and the bi- 

 valent zirconium monoxide ZrO, which has no independent existence. 

 It has been reported that the sesquioxide ion (also bivalent), Zr2 03, has 

 been found under certain conditions, but this has been brought into 

 question by later work. Recently it has been suggested that both 

 the quadrivalent elementary ion and the bivalent zirconyl ion may 

 be present in the same compound. While this is not impossible, it 

 does not appear to be the only explanation of the results obtained. 

 The complex ions have been found by various investigators to migrate 

 with the negative stream as well as with the positive. This, of 

 course, is to be expected in true chemical compounds where one is 

 dealing with an amphoteric element. Sometimes it is doubtless to 

 be attributed to the colloidal nature of the product under examina- 

 tion. 



Zirconium forms binary compounds with a number of the ele- 

 ments. The evidence is against the existence of a hydride ZrH4. 

 The hydride reported as ZrH2 may contain only absorbed hydrogen. 

 This hydrogen is lost at a higher temperature. Nitrogen combines 

 with the heated element, forming various compounds. This nitrogen 

 is also driven off below 1000°. Compounds with the halogens are 

 stable up to high temperatures and the oxide is dissociated only at 

 the temperature reached in an electric furnace. 



The oxide Zr02 forms at least two hydroxides. The normal hy- 

 droxide, or zirconium hydroxide Zr(0H)4, is easily hydrolyzed in the 



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