Legend The pnictogens[1] (/ˈpnɪktədʒən/ or /ˈnɪktədʒən/; from Ancient Greek: πνῑ́γω "to choke" and -gen, "generator") are the chemical elements in group 15 of the periodic table.

Group 15 consists of the elements nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi), and moscovium (Mc).

In semiconductor physics, it is still usually called Group V.[3] The "five" ("V") in the historical names comes from the "pentavalency" of nitrogen, reflected by the stoichiometry of compounds such as N2O5.

Like other groups, the members of this family manifest similar patterns in electron configuration, notably in their valence shells, resulting in trends in chemical behavior.

Magnetic properties of pnictide compounds span the cases of diamagnetic systems (such as BN or GaN) and magnetically ordered systems (MnSb is paramagnetic at elevated temperatures and ferromagnetic at room temperature); the former compounds are usually transparent and the latter metallic.

When these substances react with various chemicals of the body, they create strong free radicals that are not easily processed by the liver, where they accumulate.

When a pnictogen forms only three single bonds, effects of the lone pair typically results in trigonal pyramidal molecular geometry.

The light pnictogens (nitrogen, phosphorus, and arsenic) tend to form −3 charges when reduced, completing their octet.

However heavier pnictogens are more likely to form the +3 oxidation state than lighter ones due to the s-shell electrons becoming more stabilized.

Crystal solids featuring pnictogens fully reduced include yttrium nitride, calcium phosphide, sodium arsenide, indium antimonide, and even double salts like aluminum gallium indium phosphide.

Nitrogen(III) oxide can only be isolated at low temperatures, and nitrous acid is unstable.

Phosphorus forms a +III oxide which is stable at room temperature, phosphorous acid, and several trihalides, although the triiodide is unstable.

They also form related fluoride-anions, hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate, that function as non-coordinating anions.

However, for bismuth, the +5 oxidation state becomes rare due to the relativistic stabilization of the 6s orbitals known as the inert-pair effect, so that the 6s electrons are reluctant to bond chemically.

The pnictogens exemplify the transition from nonmetal to metal going down the periodic table: a gaseous diatomic nonmetal (N), two elements displaying many allotropes of varying conductivities and structures (P and As), and then at least two elements that only form metallic structures in bulk (Sb and Bi; probably Mc as well).

For instance, at STP nitrogen is a transparent non-metallic gas, while bismuth is a silvery-white metal.

The nitrogen compound sal ammoniac (ammonium chloride) has been known since the time of the Ancient Egyptians.

In the 1760s two scientists, Henry Cavendish and Joseph Priestley, isolated nitrogen from air, but neither realized the presence of an undiscovered element.

Brandt produced the element by heating evaporated urine and condensing the resulting phosphorus vapor in water.

Brandt initially thought that he had discovered the Philosopher's Stone, but eventually realized that this was not the case.

[15] It can also be used as a mnemonic for the two most common members, P and N. The term "pnictogen" was suggested by the Dutch chemist Anton Eduard van Arkel in the early 1950s.

[14] Phosphorus occurs in minerals of the apatite family, which are the main components of the phosphate rocks.

Arsenic constitutes 1.5 parts per million of the Earth's crust, making it the 53rd most abundant element.

[17] The principal method for producing phosphorus is to reduce phosphates with carbon in an electric arc furnace.

[21] Moscovium is produced a few atoms at a time in particle accelerators by firing a beam of calcium-48 ions at americium-243 until the nuclei fuse.

[22] Nitrogen is a component of molecules critical to life on earth, such as DNA and amino acids.

[14] Phosphorus in the form of phosphates occur in compounds important to life, such as DNA and ATP.

[23] The build-up of nitrogen bubbles in the blood, such as those that may occur during scuba diving, can cause a condition known as the "bends" (decompression sickness).

Breathing in phosphorus in its gaseous form can cause an industrial disease called "phossy jaw", which eats away the jawbone.

[12] The lethal dose of arsenic for a typical adult is 200 mg and can cause diarrhea, vomiting, colic, dehydration, and coma.