362 On a New Metal, Pelopium, 
pelopate of soda formed dissolves entirely in water. 
When the three acids are fused with carbonate of potash, they 
be separated in any manner. 
. The combinations of tantalic acid with the alkalies, are char- 
acterized by their passing on all occasions into insoluble acid 
salts, especially on boiling and evaporating their solutions. The 
solutions of the alkaline pelopates exhibit this property in a far 
less degree, those of the niobates not at all. Insoluble acid mio- 
bates of potash or soda can only be produced by not fusing the 
acid a sufficient time with the carbonates. 
Tantalic acid is soon and entirely precipitated from. its alka- 
line solutions by carbonic acid as an acid salt; the same is the 
case with pelopic acid, but with greater difficulty and far more 
slowly. It is owing to this that the neutral solution of tantalite 
of soda becomes turbid even by exposure to the air, while that of 
the pelopate of soda does not become turbid even after long ex- 
posure, which is characteristic of it. Carbonic acid produces @ 
precipitate in the solution of alkaline niobate only after a consid- 
erable length of time, which, however, is again dissolved by mv 
water. - 
When the solutions of the alkaline tantalates and pelopates are 
treated with an excess of hydrochloric acid, the eliminated acids 
dissolve to faintly opaline liquids. Sulphuric acid produces 
these solutions precipitates, and separates the acids on boiling; 
however, only the pelopic acid entirely, and but partly the tantalic 
acid. Hydrochloric acid precipitates the acid from the solutions 
of the alkaline niobates in the cold, and still more so on boiling ; 
an excess of hydrochloric acid merely dissolves slight traces. 
This behavior is interesting, since we have seen that unr 
der other circumstances niobic acid may be wholly soluble n hy- 
drochloric acid. Sulphuric acid precipitates niobic acid from 1's 
alkaline solutions even in the cold. He 
> From the solutions of the alkaline tantalates the acid is entire” 
Jy precipitated, without the assistance of heat, by chlorid of 
ammonium, pelopi¢ acid less perfectly, and niobic acid still less. 
