106 Mixter — Formation of Trisodium Orthopliosphate, etc. 



Heat observed 17,660° 17,766° 



" of oxidation of sulphur..— 5,271° — 5,271 c 



" " " " iron — 48° — 48 c 



" " oxygen absorbed —60° — 72 c 



12,281° 12,375° 



The mean result for 240*4 grams of antimony is 296,300°. 

 As an excess of sodium oxide was present in the fusions 

 Na s Sb0 4 must have been formed, hence we have 



5Na 2 2 + 2Sb + 2^a 3 Sb0 4 + 2Na„0 + 296,300° 



5Na 2 + 50 = ._/. 97,000° 



3Na 2 + 2Sb + 50 = 2Na,Sb0 4 + --- 393,300° 



Antimony Pentoxide. 



The preparation of the pentoxide was made as follows : 

 antimony was completely oxidized by prolonged digestion with 

 hot concentrated nitric acid, and the antimonic acid obtained 

 was washed to remove soluble impurities. It was converted 

 into oxide by heating in an electric furnace until the weight 

 remained constant at about 400°. The product was allowed to 

 cool in a closed tube, as antimony pentoxide absorbs water 

 from the air. It was free from a lower oxide and 1*7662 

 grams yielded 1*6784 grams of Sb 2 4 , which is equivalent to 

 1*7662 grams of Sb 2 5 . For the following experiments anti- 

 mony pentoxide was weighed in a stoppered bottle and mixed 

 with the sulphur and sodium peroxide in a closed bomb. 



Antimony pentoxide 



Sul phur 



Sodium peroxide 



Water equivalent of system 

 Temperature interval 



Heat observed _ 



" of oxidation of sulphur 

 " " " " iron . . . 

 " " oxygen evolved 



For 1 gram of Sb 2 5 



The result of 4 should not be included in the final value as 

 the oxygen evolved was lost. The mean of the other two is 

 511 and for 320*4 grams it is 163,700°. 



Antimony Trioxide. 

 Antimony trioxide was made by treating the trichloride with 

 dilute ammonia, washing the product thoroughly and then 



3 



4 



5 



10*059 gr 



. 10-007 gr 



10-673 gr. 



2*000 " 



2*000 " 



2-000 " 



21 " 



23 



21 " 



00 



1,028 " 



1,034 " 



3*789° 



3-834° 



3-900° 



15,535° 



15,444° 



15,733° 



-10,542° 



— 10,542° 



— 10,542° 



— 48° 



— 48° 



— 48° 



+ 151° 





+ 359° 



5,096° 



4,854° 



5,502° 



507° 



485° 



515° 



