of Molybdenum and some of its Compounds. 431 



have always obtained the neutral salt only, and are therefore 

 led to doubt the existence of this basic salt. 



Trimolybdate of Baryta, BaO, 3Mo0 3 + 3HO.— A solution 

 of the trimolybdate of potash was mixed with chloride of ba- 

 rium, when a flocculent precipitate subsided. It is somewhat 

 soluble in pure water. After washing and drying, it forms 

 a yellowish white horny mass, which adheres very firmly to 

 the filter and is brittle. On ignition it parts with water, fuses, 

 and solidifies on cooling to a yellowish crystalline mass. 



Analysis. — 0*9854? grm. salt lost on ignition 0*0829, and gave 

 0*347 sulphate of baryta = 0*2261 baryta. 



The hydrated salt has, according to theory and analysis, the 

 following composition : — 



a. Calc. b. Calc. Found. 



1 at. Baryta 955290 24-125 955-290 24-368 22-946 



3 at. Molybdic acid 2666966 67-353 2627*487 67*024 68-641 

 3 at. Water 337*437 8522 337*437 8-608 8-413 



3959-693 100000 3920214 100000 100-000 

 and the anhydous salt 



a. Calc. b. Calc. Found. 



1 at. Baryta 955-290 26373 955-290 26-663 25054 



3 at. Molybdic acid 2666-966 73-627 2627-487 73-337 74-946 



3622 256 100000 3582-777 100000 100000 

 Double salt of Baryta, BaO, 2M0O 3 + BaO, 3M0O 3 + 6 HO. 

 — This salt is obtained by decomposing the corresponding am- 

 monia salt with chloride of barium as a flocculent white pre- 

 cipitate. It is amorphous and somewhat easily soluble in 

 water ; on ignition it parts with its water with traces of am- 

 monia, fuses, and solidifies into a crystalline mass on cooling. 

 Analysis. — 0*872 grm. salt lost by ignition 0*0793, and gave 

 0*3575 sulphate of baryta = 0*233 baryta. Theory and ana- 

 lysis give the following composition for the hydrated salt. 



a. Calc. b. Calc. Found. 



2 at. Baryta 1910-580 27176 1910-580 27*433 26714 



5 at. Molybdic acid 4444-830 63-224 4379-145 62-877 64-192 



6 at. Water 674-874 9-600 674*874 9-690 9094 



7030-284 100000 6964-599 100000 100000 

 and for the anhydrous salt — 



a. Calc. b. Calc. Found. 



2at.Baryta 191058 30-062 1910-580 30376 29393 



5 at. Molybdic acid 4444-83 69938 4379-145 69-624 70607 



635541 100000 6289725 100-000 100-000 

 On attempting to decompose the above-described double 

 salt of potash, in order to obtain the corresponding baryta salt, 

 by adding the dry potash salt gradually and with constant agi- 

 tation to a dilute solution of chloride of barium, a bulky pre- 



