MICROCHEMICAL REACTIONS OF BISMUTH 
401 
water causes a precipitate of antimonyl (or bismuthyl) chloride. 
Then very carefully add hydrochloric acid with thorough stirring, 
until the precipitate just dissolves. 
EXPERIMENTS. 
Defer until Bi is being studied. 
ANTIMONATES. 
The composition of the various antimonates commercially 
available appears to be quite uncertain. The only one of im¬ 
portance is the potassium salt sold variously as potassium anti- 
monate, metantimonate or pyroantimonate; it usually conforms 
fairly closely to the formula H2K2Sb207 • 6 H2O. It is difficultly 
soluble even in boiling water. 
Sodium salts in neutral solution yield, with antimonates of this 
type, very insoluble sodium pyroantimonate, separating as tiny 
lenticular grains or larger fusiform crystals singly or uniting in 
more or less globular masses. From dilute solutions what appear 
to be tetrahedra, octahedra or rectangular prisms are formed. 
Although appearing to be isometric the crystals are to be referred 
to the tetragonal system. 
Magnesium salts in neutral solution yield H2MgSb207 • 9 H2O 
first as an amorphous precipitate, later crystallizing in thin 
transparent colorless hexagonal plates, and as small, irregular 
spherulites. Occasionally stars or rosettes or short hexagonal 
prisms are obtained. The magnesium salt is dimorphic, being 
either hexagonal or monoclinic according to conditions. 
Of the two tests that with sodium is the more satisfactory. 
If it is necessary to neutralize a test drop in testing for anti¬ 
monates use potassium carbonate. 
Ammonium salts interfere with the sodium and magnesium 
tests. 
BISMUTH. 
Crystal Forms and Optical Properties of Common Salts 
of Bismuth. 
A. ISOTROPIC. 
