30 JOURNAL OF THE 
of needle crystals, similar to, but much smaller than, the 
above obtained. ‘They were washed four times with cold _ 
water, dried to a powder between filter paper and anal- 
yzed :— 
Found Cale. for ZrBr(OH)3.H2,0O. 
ZrO 2 36.86 36.35 ofro1 
Br 32.49 33.33 
An investigation of the gelatinous oxybromide of zirco- 
nium showed that it was a hydrogele. On dialysis the 
small amount of crystalline oxybromide present passed 
through the membrane. At the same time the gelatinous 
compound, if it may we so termed, slowly decomposed 
into zirconium hydroxide and hydrobromic acid, the lat- 
ter gradually passing through the septum while the for- 
mer remained behind. 
ZIRCONIUM IODIDE. 
Zirconium tetraiodide has been prepared by Dennis and 
Spencer (Jour. Amer. Chem. Soc. XVIII. 673) by passing 
hydrogen iodide over heated zirconium. I: 1s singuiarly 
lifferent from the corresponding chlorine and bromine 
( 
compounds. It forms a white crystalline sublimate in- 
soluble in water and acids, not hygroscopic and showing 
no tendency to form oxyiodides with water. 
According to Melliss = zirconium oxyiodide 
is not formed by dissolving Zr(OH), in HI. Hinzberg (An- 
nalen 239. 253) secured an oxyiodide by precipitating a 
solution of Zr(SO,), with Bal, in equivalent amounts. 
The solution was evaporated oyer H,SO, and the crystals 
washed with carbon bisulphide and the analysis gave 
ZrO) 3,0. 
In our experiments we found that zirconium hydroxide 
when precipitated cold was soluble to a small extent in 
strong aqueous hydriodic acid or could be dissolved by 
passing hydrogen iodide into water in which the zirco- 
nium hydroxide was suspended. Evaporation of this 
solution over sulphuric acid or calcium chloride gave 
