2. (Chem.) A poisonous nonmetallic element of the nitrogen
group, obtained as a white, or yellowish, translucent waxy
substance, having a characteristic disagreeable smell. It
is very active chemically, must be preserved under water,
and unites with oxygen even at ordinary temperatures,
giving a faint glow, -- whence its name. It always occurs
compined, usually in phosphates, as in the mineral
apatite, in bones, etc. It is used in the composition on
the tips of friction matches, and for many other purposes.
The molecule contains four atoms. Symbol P. Atomic weight
31.0.
3. (Chem.) Hence, any substance which shines in the dark like
phosphorus, as certain phosphorescent bodies.
{Bologna phosphorus} (Chem.), sulphide of barium, which
shines in the dark after exposure to light; -- so called
because this property was discovered by a resident of
Bologna. The term is sometimes applied to other compounds
having similar properties.
{Metallic phosphorus} (Chem.), an allotropic modification of
phosphorus, obtained as a gray metallic crystalline
substance, having very inert chemical properties. It is
obtained by heating ordinary phosphorus in a closed vessel
at a high temperature.
{Phosphorus disease} (Med.), a disease common among workers
in phosphorus, giving rise to necrosis of the jawbone, and
other symptoms.
{Red, or Amorphous}, {phosphorus} (Chem.), an allotropic
modification of phosphorus, obtained as a dark red powder
by heating ordinary phosphorus in closed vessels. It is
not poisonous, is not phosphorescent, and is only
moderately active chemically. It is valuable as a chemical
reagent, and is used in the composition of the friction
surface on which safety matches are ignited.
{Solar phosphori} (Chem.), phosphorescent substances which
shine in the dark after exposure to the sunlight or other
intense light.