Phosphorus

P	15
Phosphorus

Abundance: 0.3%

Phosphorous, periodic table P, is a light metal. It's most common isotope is P_{31 ,}with 16 neutrons.

Phosphorous is one of the "CHNOPS" elements (Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, & Sulfur). All life is 99% composed of these elements. Of all the CHNOPS elements, phosphorus is the rarest one. Fortunately, Mars seems to be fairly rich in phosphates, the common mineral form of Phosphorus (PO4-). It is normally combined with other elements forming more complex minerals.

Availability

Phosphorous is available on Mars as phosphates. The Martian mantle is richer in potassium and phosphorus than Earth's, so the resource should be widely available, although concentrated ores need to be identified by exploration. The Columbia hills in Gusev crater have been shown by the Spirit rover to contain Phosphorus.

Applications

• Phosphorous, with nitrogen, is one of the limiting factors of plant growth.
• The human body contains, on average, 1.5 kg of phosphorus, mostly in bones, but also in DNA and soft tissues.
• Phosphorous is a plant fertilizer, required for DNA, energy storage and a number of functions in plants. The form usually used for agriculture is Calcium Phosphate, an oxide and calcium compound, with the chemical formulae CaH2(PO4)2. Calcium Phosphate is obtained on Earth using Sulfuric_acid treatment of phosphatic minerals. It is the main industrial use of sulfuric acid. Sulfuric acid should be a by product of many industrial processes on Mars.

Pathfinder gave P concentrations that ranged from 0.4 to 0.7 weight percent for rocks and from 0.3 to 1.2 weight percent for soils. This is about 5 times greater than Earth. Phosphorous is a volatile element, so Mars (which formed farther from the sun) was expected to have a greater proportion than Earth.