uthate, is obtained by melting bismuth trioxide with potash, or by
igniting bismuth trioxide with potash and potassium chlorate. It is
also formed by oxidizing bismuth trioxide suspended in caustic potash
with chlorine, the pentoxide being formed simultaneously; oxidation
and potassium ferricyanide simply gives the tetroxide (Hauser and
Vanino, _Zeit. Anorg. Chem_., 1904, 39, p. 381). The hydrate,
Bi2O4.2H2O, is also known. Bismuth pentoxide, Bi2C5, is obtained by
heating bismuthic acid, HBiO3, to 130 deg.C.; this acid (in the form
of its salts) being the product of the continued oxidation of an
alkaline solution of bismuth trioxide.

Bismuth forms two chlorides: BiCl2 and BiCl3. The dichloride, BiCl2,
is obtained as a brown crystalline powder by fusing the metal with the
trichloride, or in a current of chlorine, or by heating the metal with
calomel to 250 deg. Water decomposes it to metallic bismuth and the
oxychloride, BiOCl. Bismuth trichloride, BiCl3, was obtained by Robert
Boyle by heating the metal with corrosive sublimate. It is the final
product of burning bismuth in an excess of chlorine. It is a white
substance, melting at 225 deg.-230 deg. and boiling at 435 deg.-441
deg. With excess of water, it gives a white precipitate of the
oxychloride, BiOCl. Bismuth trichloride forms double compounds with
hydrochloric acid, the chlorides of the alkaline metals, ammonia,
nitric oxide and nitrosyl chloride. _Bismuth trifluoride_, BiF3, a
white powder, _bismuth tribromide_, BiBr3, golden yellow crystals,
_bismuth iodide_, BiI3, greyish-black crystals, are also known. These
compounds closely resemble the trichloride in their methods of
preparation and their properties, forming oxyhaloids with water, and
double compounds with ammonia, &c.

_Carbonates_.--The basic carbonate, 2(BiO)2CO3.H2O, obtained as a
white precipitate when an alkaline carbonate is added to a solution of
bismuth nitrate, is employed in medicine. Another basic carbonate,
3(BiO)2CO3.2Bi(OH)3.3H2O, constitutes the mineral bismutite.

_Nitrates_.--The normal nitrate, Bi(NO3)3.5H2O, is obtained in large
transparent asymmetric prisms by evaporating a solution of the metal
in nitric acid. The action of water on this solution produces a
crystalline precipitate of basic nitrate, probably Bi(OH)2NO3, though
it varies with the amount of water employed. This precipitate
constitutes the "magist