Phosphorus vs Phosphate
The phosphorus cycle is a biogeochemical cycle, which describes how different forms of phosphorus circulate within the earth. It is mainly restricted to the lithosphere, because phosphorus doesn’t have a gaseous phase. Phosphorus is largely found as phosphates, stored in soil, fossils, animal and plant bodies and in water systems.
Phosphorus is the 15th element in the periodic table with the symbol P. It is also in the group 15 along with nitrogen and has a molecular weight of 31 g mol-1. The electron configuration of phosphorus is 1s2 2s2 2p6 3s2 3p3. It is a multivalent atom and can form +3, +5 cations. Phosphorus has several isotopes, but P-31 is common with 100% abundance. P-32 and P-33 isotopes are radioactive, and can emit pure beta particles. Phosphorus is very reactive, therefore, can’t present as a single atom. There are two major forms of phosphorus present in the nature as white phosphorus and red phosphorus. White phosphorus has four P atoms arranged in tetrahedral geometry. White phosphorus is a pale yellow color transparent solid. It is highly reactive as well as highly toxic. Red phosphorus exists as a polymer and upon heating white phosphorus, this can be obtained. Other than white and red phosphorus, there is another type, known as black phosphorus and it has a structure similar to graphite.
Phosphate is the common inorganic form of phosphorus, which is present in the natural environment. They exist as deposits/ rocks and these are mined to get required phosphorous. One phosphorus atom is bonded with four oxygens to form a -3 polyatomic anion. Because of the single bonds and double bond, between P and O, phosphorus has a +5 oxidation state in here. It has a tetrahedral geometry. Following is the structure of phosphate anion.
Phosphate anion can combine with different cations to form numerous ionic compounds. When there are three hydrogen atoms connected, it is known as the phosphoric acid. Phosphorus is an abundant mineral in the body, especially as phosphates. For example, there are phosphate groups in DNA, RNA, ATP, phospholipids, in bones etc. Low phosphate levels in bones and blood may cause several diseases to human. It is essential to include phosphate sources into our diet. Phosphorus can be taken into our body as phosphates from dairy products, fish, meat, eggs, grains, etc.
Phosphorus is also an essential macro element for plants. Therefore, fertilizers contain phosphates in large amounts. However, if these phosphates are washed away and accumulated in water bodies, they can cause water pollution. This condition is known as eutrophication. What happens in this case is, when there is a high nutrient content in water bodies phytoplankton will grow rapidly because they also require nutrients like phosphates for their growth. When this happens, the dissolved oxygen in the water will be absorbed by phytoplanktons largely, where the other living organisms will die without oxygen.
What is the difference between Phosphorus and Phosphate?
- Phosphorus is a single atom and phosphate is a polyatomic anion.
- Phosphorus is not stable as an element, but phosphate is stable.
- Phosphorus has the capability to form cations, but phosphate is an anion.
- We take phosphorus into our bodies in the form of phosphates.