A Manual of the Chemistry of the Carbon Compounds

102 TEE CHEMI8THY OF
in sealed tubes for forty-eight hours. It is also readily formed by
heating bromoform -with bromine and iodine. Tetrabromomethane
crystallizes in white shining plates, melting at 91°, and boiling with
slight decomposition at 189-5°.
lodofom., Tri-wdomethane CHIy—This compound is formed by
acting with potash or potassium carbonate and iodine upon ethyl
alcohol, aldehyde, acetone, and many other carbon compounds, but
pure methyl alcohol yields no iodoform. It crystallizes in yellow
scales, emells like saffron, melts at 120°, and is decomposed at a
higher temperature, but may be volatilized in a current of steam.
On heating it in a closed tube for some time to 150°, methene diiodide
or di-iodmnetlianc CH2I2 is formed, a compound which can also
be obtained by heating chloroform with fuming hydriodic acid:—
CHCls + 4HI = CH2Ig + 3HC1 + I3
This compound is a yellowish heavy liquid, which boils at 181° and
at — 2° solidifies to a crystalline mass.
Nitroehioroform, Nitrotrkhloivmetlmne, or CJdoi-opicrin C(NO2)C1S is
formed when methyl- or ethyl alcohol are distilled with salt, saltpetre,
and sulphuric aeid, and also by the distillation of many nitro-compounds
with a solution of bleaching powder.
It is best prepared by mixing in a still, ten parts of bleaching
powder with water to form a paste, and adding one part of picric
acid CaH2(N02)sOH; a violent reaction sets in and the chloropicrin
distils over. It is a colourless liquid, possessing a most irritating
smell, and boiling at 112°. On distilling it with acetic"acid and ironfilings
it is reduced to methylamine:—
61fa = CH^NH, + SHC1 4 2fla0
Nitroform, Trinilromctlianc, CHtNO^g.—This body is produced by
decomposing trijiitroacetonilriU C2(NO3)3N (see Fulminates) with
water :—
Nitroform .is a weak acid; the product of the reaction consists
therefore of the ammonium salt. On acting on trinitroacetonitrile with
caustic potash, tbe potassium salt CKfNO^g is obtained, which forms
yellow crystals. On adding concentrated sulphuric acid to one of
these salts, nitroform separates out as a light oily layer, which on
cooling solidifies, forming colourless, cubical crystals. It has an unpleasant
smell and bitter taste, and is highly inflammable, In water
it dissolves with a yellow colour. On quickly heating it or oue of its
salts, it decomposes with a violent explosion.
Tetranitromthane (/(NO^.—-By passing a current of air through a
solution of nitroform in a mixture of concentrated nitric and sulphuric
adds, tetranitromethane distils over:—