It crystallizes in monoclinic prisms of composition Ba(103) 2 H 2 O, and is only very sparingly soluble in cold water.
The bromide and iodide crystallize from hot solutions in anhydrous cubes; from solutions at ordinary temperatures in monoclinic prisms with 2H 2 O; and at low temperatures with 5H 2 O.
This is illustrated by the hexagonal pyrargyrite 3Ag 2 S Sb 2 S 3, and proustite, 3Ag 2 S As2S3, and the monoclinic pyrostilpnite, isomeric with pyrargyrite, and xanthoconite, isomeric with proustite.
Ferric nitrate, Fe(NO3) 3, is obtained by dissolving iron in nitric acid (the cold dilute acid leads to the formation of ferrous and ammonium nitrates) and crystallizing, when cubes of Fe(NO3)3.6H20 or monoclinic crystals of Fe(N03)3.9H20 are obtained.
Evaporation of a solution at ordinary temperatures gives colourless monoclinic prisms of Th(SO 4) 2.9H 2 O, which is isomorphous with uranium sulphate, U(S04)2.9H20.
Crystals of azurite belong to the monoclinic system; they have a vitreous lustre and are translucent.
The crystals belong to the monoclinic system, and it is a curious fact that in habit and angles they closely resemble pyroxene (a silicate of calcium, magnesium and iron).
By plotting the specific volumes of these mixed crystals as ordinates, it is found that they fall on two lines, the upper corresponding to the orthorhombic crystals, the lower to the monoclinic. From this we may conclude that these salts are isodimorphous: the upper line represents isomorphous crystals of stable orthorhombic magnesium sulphate and unstable orthorhombic ferrous sulphate, the lower line isomor phous crystals of stable monoclinic ferrous sulphate and unstable monoclinic magnesium sulphate.
It is a soft, flocculent powder, which on sublimation forms transparent, monoclinic crystals.
The bicarbonate forms large monoclinic prisms, permanent in the air.