Professor Berzelius on Thorina, 9& 



slightly. In cold nitro-muriatic acid also it suffers no change; 

 but when heated it dissolves without residue, giving off nitrous 

 acid gas. The solution contains sulphate of thorina. 



4th. Thorium and phosphorus. When thorium is heated 

 in gaseous phosphorus, they unite with the development of 

 heat and light. The phosphoret of thorium is dark-gray, has 

 the metallic lustre, and resembles graphite. It is insoluble in 

 water. When heated, it takes fire, and is converted into the 

 phosphate of thorina. 



5th. Salts of thorium. The salts which thorium gives, as 

 well with salt-formers^ as in the state of oxide with the oxy- 

 acids, are distinguished by a strong and pure astringent taste, 

 which is not accompanied by anything of sour, sweet, or bitter, 

 and which most resembles that of pure tannin. In taste they 

 also resemble nearest the salts of zirconium. Their solutions 

 are precipitated by oxalic acid, and by the cyanide of iron and 

 potassium, of a white colour, and are rendered muddy by sul- 

 phate of potash, which is dissolved by them. 



These three re-agents distinguish them from all other un- 

 mixed salts, except those of the protoxide of cerium, from 

 which salts they are distinguished by this — that the colourless 

 precipitate by caustic alkali does not become yellow in the 

 open air, as is the case with the cerium salts. The salts of 

 thorina are decomposed by a red heat, and leave the earth in 

 an isolated state, and they lose their acids more easily than 

 zirconia. 



(A.) Haloidsalts. 



Chloride of thorium is formed by mixing thorina with pure 

 sugar, charring the mixture thoroughly in a covered platinum 

 crucible, afterwards, when heated to redness in a porce- 

 lain tube, passing over it a stream of dry chlorine gas. The 

 decomposition takes place very slowly, and the chloride of 

 thorium is not particularly volatile. The most of it is deposited 

 where the tube ceases to be red ; the mass to be decomposed, 

 therefore, should not be allowed to reach so far, if we wish to 

 make a distinct separation. The chloride of thorium deposits 

 itself in the form of a white crystalline ring, and white fumes^ 



* The following are what Berzelius calls saitbilder, ta/t-buildert—cblonnef 

 iodine, bromine, cyanogen, fluorine, and sulpho-cyanogen — the base of the hydro- 

 sulpho-cyanic acid. — Translator. 



