ATOMIC WEIGHTS 287 



ZIECONIUM. 



The atomic weight of zireonimn has been determined by Berzelius, 

 Hei-mann, Marignac, Weibiill, Bailey and Venable. Berzelius ' ignited' 

 the neutral sulphate, and thus ascertained the ratio in it between the 

 ZrO, and the SO3. Putting SO, at 100, he gives the following pro- 

 portional quantities of ZrO, : 



75.84 



75.92 



75.80 



75.74 



75.97 



75.85 



Mean, 75.853, ± .023 



This gives 43.134, ±.0142 as the percentage of zirconia in the sulphate. 

 Hence Zr = 89.46. 



Hermann's '^ estimate of the atomic weight of zirconium was based 

 upon analyses of the cliloride, concerning which he gives no details nor 

 weighings. From sublimed zirconium chloride he finds Zr = 831.8, when 

 = 100; and from two lots of the basic chloride 2ZrOCl,.9HoO, Zr = 

 835.65 and 851.40, respectively. The mean of all three is 839.62 ; whence, 

 with modern formula, Zr = 89.56. 



Marignac's results ^ were obtained by analyzing the double fluoride of 

 zirconium and potassium. His weights are as follows : 



1.000 grm. gave .431 grm. ZrO, and .613 grm. K^SO^. 

 2.000 " .864 " 1.232 



.654 " .282 " .399 



5.000 " 2.169 " 3.078 



These figures give us three ratios. A, the ZrOo from 100 parts of salt; 

 B, the K2SO4 from 100 parts of salt; and C, the ZrOo proportional to 

 100 parts of K^SO^ : 



A. B. G. 



43.100 61.300 70.310 



43.200 61.600 70.130 



43.119 61.000 70.677 



43.380 61.560 70.468 

 Mean, 43.200, ± .043 Mean, 61.305, ± .094 Mean, 70.396, ± .079 



Hence Zr = 90.03 91.54 90.68 



1 Poggend. Anna!., 4, 126. 1S25. 



= Journ. prakt. Chem., 31, 77. Berz. Jahresb., 25, 147. 



^ Ann. Chim. Phys. (3), 60, 270. 1S60. 



