PHOSPHORUS CYCLE
BY: ALYSSE RIGGS, ALYSSA MCCARTT, JENNA
MCCARTY, JULIE DAVIS
The Chemical Reactions Involved

Reaction of phosphorus with air: White phosphorus
glows in the dark when exposed to damp air in a
process known as chemuluminescence. White
phosphorus must be handled with great care. It
spontaneously ignites in air at about room
tetraphosphorus decaoxide.
P4 (s)+502 (g)
P4010(s)
Reactions Cont.

Reaction of phosphorus with the halogens: white
phosphorus, P4, reacts vigorously with all the halogens
at room temperature to form phosphorus trihalides. So,
it reacts with fluorine, chlorine, bromine, and iodine, to
form respectively phosphorus (III) fluoride, phosphorus
(III) chloride, phosphorus (III) bromide, and phosphorus
(III) iodide.
P4(s) + 6F2(g)
P4(s) + 6Cl2(g)
P4(s) + 6Br2(g)
P4(s) + 6I2(g)
4PF3(g)
4PCl3(I)
4PBr3(I)
4PI3(g)
Reactions Cont.
The reactions involving Phosphorus are:





Substitution reactions: one group on phosphorus is replaced by
another group; has two possiblities.
Oxidation reactions: oxidation state of phosphorus increases after
the reaction; the reverse is Reduction reaction.
Addition reactions: another molecule adds to phosphorus; the
reverse is dissociation/elimination reaction.
Elimination reactions: one molecule leads to two molecules.
Oxidative addition: the reaction combines both Oxidation and
Addition reactions.
Inorganic and Organic Reservoirs


Organic phosphorus sources are the guano hills
before the coast of Peru that developed by
accumulation of bird excrements and that are
determinedly excavated since the 19th century.
Natural inorganic phosphorus deposits occur
primarily as phosphate in the mineral apatite.
Apatite is defined as a natural, variously colored
calcium fluoride phosphate, Ca5F(PO4)3, with
chlorine, hydroxyl, and carbonate sometimes
replacing the fluoride
Pathway of Movement


The phosphorus cycle is the biogeochemical cycle that
describes the movement of phosphorus through the geosphere,
hydrosphere, and biosphere. Unlike the other major
biogeochemical cycles (oxygen, carbon, nitrogen, and water),
the atmosphere does not play a significant role in the
movements of phosphorus because phosphorus and
phosphorus-based compounds are usually solids at the typical
ranges of temperature and pressure found on Earth.
The phosphorus cycle reflects the harmonious interactions
between organisms and their biotic and abiotic environments,
with phosphorus flowing through each compartment by give
and receive actions and allowing life to exist. However,
sometimes the harmony that has been built up over many years
is disrupted by human beings, who may put excessive amounts
of phosphorus into a particular ecosystem through fertilizer,
sewage, or other means.
Movement Cont.
Impacts of Human Intervention



Human influences on the cycle mainly from use of
commercial fertilizer
The concentration of phosphorus in the fertilizer
create a runoff effect when it rains, and is
deposited in lakes, rivers, streams, etc, and leads to
eutrophication.
Eutrophication: Natural process by which lakes,
streams, etc. receive excess nutrients that stimulate
excessive plant growth.
Impacts Cont.

Humans can also alter the cycle in another way by
cutting down the rain forest through the use of
agricultural fertilizer. These runoffs provide most of
the phosphate found in water, increase of
phosphate in rivers and streams, along with other
bodies of water.
Creators
Alyssa McCarrtt
Aylsse Riggs
Jenna McCarty
Julie Davis