二氧化硫

Sulphur \Sul"phur\, n. [L., better sulfur: cf. F. soufre.]
1. (Chem.) A nonmetallic element occurring naturally in large
quantities, either combined as in the sulphides (as
pyrites) and sulphates (as gypsum), or native in volcanic
regions, in vast beds mixed with gypsum and various earthy
materials, from which it is melted out. Symbol S. Atomic
weight 32. The specific gravity of ordinary octohedral
sulphur is 2.05; of prismatic sulphur, 1.96.

Note: It is purified by distillation, and is obtained as a
lemon-yellow powder (by sublimation), called flour, or
flowers, of sulphur, or in cast sticks called roll
sulphur, or brimstone. It burns with a blue flame and a
peculiar suffocating odor. It is an ingredient of
gunpowder, is used on friction matches, and in medicine
(as a laxative and insecticide), but its chief use is
in the manufacture of sulphuric acid. Sulphur can be
obtained in two crystalline modifications, in
orthorhombic octahedra, or in monoclinic prisms, the
former of which is the more stable at ordinary
temperatures. Sulphur is the type, in its chemical
relations, of a group of elements, including selenium
and tellurium, called collectively the sulphur group,
or family. In many respects sulphur resembles oxygen.

2. (Zo["o]l.) Any one of numerous species of yellow or orange
butterflies of the subfamily {Pierin[ae]}; as, the clouded
sulphur ({Eurymus philodice} syn. {Colias philodice}),
which is the common yellow butterfly of the Eastern United
States.

{Amorphous sulphur} (Chem.), an elastic variety of sulphur of
a resinous appearance, obtained by pouring melted sulphur
into water. On standing, it passes back into a brittle
crystalline modification.

{Liver of sulphur}. (Old Chem.) See {Hepar}.

{Sulphur acid}. (Chem.) See {Sulphacid}.

{Sulphur alcohol}. (Chem.) See {Mercaptan}.

{Sulphur auratum} [L.] (Old Chem.), a golden yellow powder,
consisting of antimonic sulphide, {Sb2S5}, -- formerly a
famous nostrum.

{Sulphur base} (Chem.), an alkaline sulphide capable of
acting as a base in the formation of sulphur salts
according to the old dual theory of salts. [Archaic]

{Sulphur dioxide} (Chem.), a colorless gas, {SO2}, of a
pungent, suffocating odor, produced by the burning of
sulphur. It is employed chiefly in the production of
sulphuric acid, and as a reagent in bleaching; -- called
also {sulphurous anhydride}, and formerly {sulphurous
acid}.

{Sulphur ether} (Chem.), a sulphide of hydrocarbon radicals,
formed like the ordinary ethers, which are oxides, but
with sulphur in the place of oxygen.

{Sulphur salt} (Chem.), a salt of a sulphacid; a sulphosalt.


{Sulphur showers}, showers of yellow pollen, resembling
sulphur in appearance, often carried from pine forests by
the wind to a great distance.

{Sulphur trioxide} (Chem.), a white crystalline solid, {SO3},
obtained by oxidation of sulphur dioxide. It dissolves in
water with a hissing noise and the production of heat,
forming sulphuric acid, and is employed as a dehydrating
agent. Called also {sulphuric anhydride}, and formerly
{sulphuric acid}.

{Sulphur whale}. (Zo["o]l.) See {Sulphur-bottom}.

{Vegetable sulphur} (Bot.), lycopodium powder. See under
{Lycopodium}.


Sulphuryl \Sul"phur*yl\, n. [Sulphur + -yl.] (Chem.)
The hypothetical radical {SO2}; -- called also {sulphon}.

{Sulphuryl chloride}, a chloride, pungent, fuming liquid,
{SO2.Cl2}, obtained by the action of phosphorus
pentachloride on sulphur trioxide. On treatment with water
it decomposes into sulphuric and hydrochloric acids, and
is hence called also {sulphuric chloranhydride}.