A Manual of the Chemistry of the Carbon Compounds

THE CARBON COMPOUNDS. 13
The monad group Uranyl UO exists in a number of uranium
compounds:—
Uranyl Chloride UO Cl
Uranyl Nitrate UO NO8
Uranyl Sulphate , uo{ SO *
Uranyl Sulphide UO { S
Such compound radicals are nothing but groups of atoms which
remain unchanged in a great number of reactions, and so far act like
a single atom ; it is therefore quite a matter of indifference whether
compound radicals can exist m the free state or not Thus the
monad and triad alcohol radicals cannot be isolated, but dyad and
tetrad radicals exist in the free state, as for example the hydrocarbons
of the ethene and ethine series.
Whilst in a great number of metamorphoses the compound radicals
remain unaltered, they undergo by other reactions manifold changes.
In some of these the carbon group is left intact: thus ethyl alcohol
yields by oxidation acetic aoid, the radical ethyl C2H6 being con*
verted into acefcyl C2H8O :~
O + O8 = °» H 8g J-0 + H.O
When we act with chlorine upon propyl chloride, the monad radical
propyl is changed into dyad propene:—
HC1
The dyad radical ethene combines with hydroiodio acid, the iodide
of monad ethyl being formed :—
But in many other chemical changes the group of carbon atoms
is broken up into two or more fragments: thm by heating acetic
aoid with an excess of caustio soda, it splits up into carbon dioxide
and methane s—<
C 4 4
By the action of the galvanic cvinent, succinio acid is decomposed
into ethene, carbon dioxide, and hydrogen:—
CaH< + 2CO4 + Ha
Such a breaking up of groups of carbon atoms takes place most
easily in those derivatives of hydrocarbons in which hydrogen has
been displaced by oxygen.
On the other hand, by joining two carbon atoms together, we are
able to bxiild up more complicated compounds from simple ones.
By heating methyl iodide with ziuc, the iodine combines with the