tincture A solution with alcohol as
the solvent (e.g. tincture of iodine).
tin(IV) hydride (stannane)A
highly reactive and volatile gas (b.p.
–53°), SnH 4 , which decomposes on
moderate heating (150°C). It is pre-
pared by the reduction of tin chlo-
rides using lithium tetrahydrido-
aluminate(III) and is used in the
synthesis of some organo-tin com-
pounds. The compound has reducing
properties.
tin(IV) oxide (tin dioxide)A white
solid, SnO 2 , insoluble in water; tetra-
hedral; r.d. 6.95; m.p. 1127°C; sub-
limes between 1800°C and 1900°C.
Tin(IV) oxide is trimorphic: the com-
mon form, which occurs naturally as
the ore cassiterite, has a rutile lat-
tice but hexagonal and rhombic
forms are also known. There are also
two so-called dihydrates, SnO 2 .2H 2 O,
known as α- and β-stannic acid.
These are essentially tin hydroxides.
Tin(IV) oxide is amphoteric, dissolv-
ing in molten alkalis to form stan-
nates; in the presence of sulphur,
thiostannates are produced.
tin plague See tin.
tin(II) sulphideA grey-black cubic
or monoclinic solid, SnS, virtually in-
soluble in water; r.d. 5.22; m.p.
882 °C; b.p. 1230°C. It has a layer
structure similar to that of black
phosphorus. Its heat of formation is
low and it can be made by heating
the elements together. Above 265°C
it slowly decomposes (disproportion-
ates) to tin(IV) sulphide and tin
metal. The compound reacts with hy-
drochloric acid to give tin(II) chloride
and hydrogen sulphide.
tin(IV) sulphide (mosaic gold)A
bronze or golden yellow crystalline
compound, SnS 2 , insoluble in water
and in ethanol; hexagonal; r.d. 4.5;
decomposes at 600°C. It is prepared
by the reaction of hydrogen sulphide
with a soluble tin(IV) salt or by the
action of heat on thiostannic acid,
H 2 SnS 3. The golden-yellow form used
for producing a gilded effect on wood
is prepared by heating tin, sulphur,
and ammonium chloride.TIPSee temperature-independent
paramagnetism.
titaniaSee titanium(iv) oxide.titanic chlorideSee titanium(iv)
chloride.
titanic tetrachlorideSee tita-
nium(iv) chloride.titaniumSymbol Ti. A white metal-
lic *transition element; a.n. 22; r.a.m.
47.9; r.d. 4.5; m.p. 1660± 10 °C; b.p.
3287 °C. The main sources are rutile
(TiO 2 ) and, to a lesser extent, il-
menite (FeTiO 3 ). The element also oc-
curs in numerous other minerals. It
is obtained by heating the oxide with
carbon and chlorine to give TiCl 4 ,
which is reduced by the *Kroll
process. The main use is in a large
number of strong light corrosion-
resistant alloys for aircraft, ships,
chemical plant, etc. The element
forms a passive oxide coating in air.
At higher temperatures it reacts with
oxygen, nitrogen, chlorine, and other
nonmetals. It dissolves in dilute
acids. The main compounds are tita-
nium(IV) salts and complexes; tita-
nium(II) and titanium(III) compounds
are also known. The element was
Ürst discovered by William Gregor
(1761–1817) in 1789.
A- Information from the WebElements site
titanium(IV) chloride (titanic chlo-
ride; titanium tetrachloride)A
colourless volatile liquid, TiCl 4 , made
by strongly heating titanium(IV)
oxide and carbon in a stream of dry
chorine gas. It fumes in moist air to
produce titanium oxychlorides. It is529 titanium(IV) chloride
t