Dictionary of Chemistry [6th Ed.]

2,4,6-trinitrophenol 536

t

b.p. 130°C. Like other aluminium

alkyls it may be prepared by reacting

a Grignard reagent with aluminium

trichloride. Aluminium alkyls are

used in the *Ziegler process for the

manufacture of high-density poly-

ethene (polythene).

2,4,6-trinitrophenol See picric

acid.

trinitrotoluene (TNT)A yellow

highly explosive crystalline solid,

CH 3 C 6 H 2 (NO 2 ) 3 ; r.d. 1.65; m.p. 82°C. It

is made by nitrating toluene (methyl-

benzene), the systematic name being

1-methyl-2,4,6-trinitrobenzene.

triol(trihydric alcohol)An *alcohol

containing three hydroxyl groups per

molecule.

trioseA sugar molecule that con-

tains three carbon atoms. See mono-

saccharide.

trioxoboric(III) acidSee boric

acid.

trioxosulphuric(IV) acidSee sul-

phurous acid.

trioxygenSee ozone.

triphenylmethylAn unusual aro-

matic compound that can exist as

an anion, cation or free radical,

(C 6 H 5 ) 3 C. Treatment of triphenyl-

carbinol in alcoholic solution with

mineral acids produces triphenyl-

methyl salts, containing the cation

(C 6 H 5 ) 3 C+, which crystallize as or-

ange-red solids. The action of sodium

on a solution of triphenylmethyl

chloride in ether produces the yellow

(C 6 H 5 ) 3 C–anion. The free radical

form is made by treating triphenyl-

methyl chloride with mercury or

zinc in the absence of oxygen.

triple bondSee chemical bond.

triple pointThe temperature and

pressure at which the vapour, liquid,

and solid phases of a substance are in

equilibrium. For water the triple

point occurs at 273.16 K and 611.2 Pa.

This value forms the basis of the

deÜnition of the *kelvin and the

thermodynamic *temperature scale.

tripletAn atomic state in which

two spin angular momenta of elec-

trons combine together to give a

total nonzero spin. A triplet state

solid

ice line

triple point

hoarfrost

line

steam

line

vapour

611.2

liquid

temperature / K

pressure / Pa

273.16

Triple point