The theory wasÜnally demolished
by Antoine Lavoisier, who showed by
careful experiments with reactions
in closed containers that there was
no absolute gain in mass – the gain
in mass of the substance was
matched by a corresponding loss in
mass of the air used in combustion.
After experiments with Priestley’s de-
phlogisticated air, Lavoisier realized
that this gas, which he named oxy-
gen, was taken up to form a calx
(now called an oxide). The role of
oxygen in the new theory was almost
exactly the opposite of phlogiston’s
role in the old. In combustion and
corrosion phlogiston was released; in
the modern theory, oxygen is taken
up to form an oxide.phonochemistryThe use of high-
frequency sound (ultrasound, with a
frequency greater than about 20 kHz)
to induce or accelerate certain types
of chemical reaction.phosgeneSee carbonyl chloride.
phosphagenA compound found
in animal tissues that provides a re-
serve of chemical energy in the form
of high-energy phosphate bonds. The
most common phosphagens are
creatine phosphate, occurring in ver-
tebrate muscle and nerves, and argi-
nine phosphate, found in most
invertebrates. During tissue activity
(e.g. muscle contraction) phospha-
gens give up their phosphate groups,
thereby generating *ATP from ADP.
The phosphagens are then reformed
when ATP is available.phosphatesSalts based formally
on phosphorus(V) oxoacids and in
particular salts of *phosphoric(V)
acid, H 3 PO 4. A large number of poly-
meric phosphates also exist, contain-
ing P–O–P bridges. These are formed
by heating the free acid and its salts
under a variety of conditions; as well
as linear polyphosphates, cyclicpolyphosphates and cross-linked
polyphosphates or ultraphosphates
are known.phosphatidesSee phospholipids.phosphideA binary compound of
phosphorus with a more electroposi-
tive element. Phosphides show a
wide range of properties. Alkali and
alkaline earth metals form ionic
phosphides, such as Na 3 P and Ca 3 P 2 ,
which are readily hydrolysed by
water. The other transition-metal
phosphides are inert metallic-looking
solids with high melting points and
electrical conductivities.phosphineA colourless highly
toxic gas, PH 3 ; m.p. –133°C; b.p.
–87.7°C; slightly soluble in water.
Phosphine may be prepared by react-
ing water or dilute acids with cal-
cium phosphide or by reaction
between yellow phosphorus and con-
centrated alkali. Solutions of phos-
phine are neutral but phosphine
does react with some acids to give
phosphonium salts containing PH 4 +
ions, analogous to the ammonium
ions. Phosphine prepared in the labo-
ratory is usually contaminated with
diphosphine and is spontaneously
Ûammable but the pure compound is
not so. Phosphine can function as a
ligand in binding to transition-metal
ions. Dilute gas mixtures of very pure
phosphine and the rare gases are
used for doping semiconductors.phosphinic acid (hypophosphorus
acid)A white crystalline solid,
H 3 PO 2 ; r.d. 1.493; m.p. 26.5°C; decom-
poses above 130°C. It is soluble in
water, ethanol, and ethoxyethane.
Salts of phosphinic acid may be pre-
pared by boiling white phosphorus
with the hydroxides of group I or
group II metals. The free acid is made
by the oxidation of phosphine with
iodine. It is a weak monobasic acid in
which it is the –O–H group that isphonochemistry 410p