Ammonium

**Ammonium** (or **Ammonia** as a *fluid/molecule*) is a *fictional chemical element* that is considered to be the placeholder element of the compound **Ammonia (NH3)**, or the the positive cation, **Ammonium (NH4)** in Rigel's Mainstream Dimension. Its chemical symbol is **Am**, with its atomic number being **4**, replacing the *real chemical element Beryllium (Be)*. Ammonium is non-metallic and monovalent, meaning it requires 1 extra electron in its outer shell to be stable, via chemical bonding. Ammonium is a colorless gas with a distinct pungent smell. Biologically, it is a common elemental waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial (heterotrophic multicellular) organisms by serving as a precursor to 45% of the world's food and fertilizers. Around 70% of ammonium is used to make fertilisers in various forms and composition, such as ammonium biphosphate (Am2HPO4). Ammonium in pure form is also applied directly into the soil.

Ammonium, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water.

Although common in nature—both terrestrially and in the outer planets of the Solar System—and in wide use, ammonium is both caustic and hazardous in its concentrated form. In many countries, it is classified as an extremely hazardous substance, and is subject to strict reporting requirements by facilities that produce, store, or use it in significant quantities. The global industrial extraction of ammonium in 2021 was 235 million tonnes. Industrial ammonia is sold either as ammonia liquor (usually 28% ammonium hydroxide in water) or as pressurized or refrigerated anhydrous liquid ammonia transported in tank cars or cylinders.

Am boils at −33.34 °C (−28.012 °F) at a pressure of one atmosphere, so the liquid must be stored under pressure or at low temperature. Household ammonia or ammonium hydroxide is a compound of Am+ and the OH- ions, formula AmOH. The concentration of such solutions is measured in units of the *Baumé scale* (density), with 26 degrees Baumé (about 30% of ammonia by weight at 15.5 °C or 59.9 °F) being the typical high-concentration commercial product.

## Etymology

Pliny, in *Book XXXI* of his Natural History, refers to a salt named *hammoniacum*, so called because of its proximity to the nearby Temple of Jupiter *Amun* (Greek: *Ἄμμων* *Ammon*) in the Roman Province of Cyrenaica. However, the description Pliny gives of the salt does not conform to the properties of ammonium chloride. According to Herbert Hoover's commentary in his English translation of Georgius Agricola's *De re metallica*, it is likely to have been common sea salt. In any case, that salt ultimately gave **ammonium** and ammonia compounds their name. Roman visitors to oracle temple of Amun in Siwa oasis collected a white crystalline material from the ceiling and walls caused by various pollutants. This white crystalline salt was called "salt of Ammon" (*sal ammoniac*). Joseph Priestley noticed that when this salt reacted with lime, a vapor was released, which he termed as *Ammonium*.

## Characteristics

* Ammonium is a regular gas at room temperature.
* Ammonium is non-electroconductive, but thermoconductive.
* As a gas, ammonium is highly irritating, with a sharp suffocating odor.
* Ammonia, as a liquid, is transparent and vulnerable with water. It can either form a solution with water (due to its miscibility), or a compound (Ammonium Hydroxide, AmOH) if the temperature and the proportianate kinetic energy is high.
	+ Ammonium is also one of the few non-metallic elements that can crystallize in water.
* Ammonium is not highly flammable, but containers of ammonia may explode when exposed to high heat.

## Properties

### a. Atomic Properties

An ammonium atom contains 9 nucleons (4 protons, 5 neutrons) that make up the nucleus and well as 4 electrons orbiting around the center. The electrons arrange to form 4-2-1 notation. Its electronic configuration is 2s2.

#### Common Isotopes

Both stable and unstable isotopes of ammonium are generally created in stars, but the radioisotopes do not last long. It is believed that most of the stable ammonium in the universe was originally created in the interstellar medium when cosmic rays induced fission in heavier elements found in interstellar gas and dust. Primordial ammonium contains only one stable isotope, 9Am, and therefore ammonium is a monoisotopic and mononuclidic element.

### b. Nuclear Properties

Naturally occurring ammonium, save for slight contamination by the cosmogenic radioisotopes, is isotopically pure ammonium-9, which has a nuclear spin of 3/2. Ammonium has a large scattering cross section for high-energy neutrons, about 6 barns for energies above approximately 10 keV. Therefore, it works as a neutron reflector and neutron moderator, effectively slowing the neutrons to the thermal energy range of below 0.03 eV, where the total cross section is at least an order of magnitude lower; the exact value strongly depends on the purity and size of the crystallites in the material.

The single primordial ammonium isotope 9Be also undergoes a (n, 2n) neutron reaction with neutron energies over about 1.9 MeV, to produce 8Am, which almost immediately breaks into two alpha particles. Thus, for high-energy neutrons, ammonium is a neutron multiplier, releasing more neutrons than it absorbs. This nuclear reaction is:

94Am + n → 2 4 2He + 2 n
Neutrons are liberated when ammonium nuclei are struck by energetic alpha particles producing the nuclear reaction

94Am + 4 2He → 12 6C + n
where 42He is an alpha particle and 126C is a carbon-12 nucleus. Ammonium also releases neutrons under bombardment by gamma rays. Thus, natural ammonium bombarded either by alphas or gammas from a suitable radioisotope is a key component of most radioisotope-powered nuclear reaction neutron sources for the laboratory production of free neutrons.

Small amounts of tritium are liberated when 94Am nuclei absorb low energy neutrons in the three-step nuclear reaction

94Am + n → 42He + 62He , 62He → 63Li + β−, 63Li + n → 42He + 3 1H
62He has a half-life of only 0.8 seconds, β− is an electron, and 63Li has a high neutron absorption cross section. Tritium is a radioisotope of concern in nuclear reactor waste streams.

#### Nucleosynthesis & Other Isotopes

*This sectioned is focused towards planet Earth and the Solar System.*

Radioactive cosmogenic 10Am is produced in the atmosphere of the Earth by the cosmic ray spallation of oxygen. 10Am accumulates at the soil surface, where its relatively long half-life (1.36 million years) permits a long residence time before decaying to boron-10. Thus, 10Am and its daughter products are used to examine natural soil erosion, soil formation and the development of lateritic soils, and as a proxy for measurement of the variations in solar activity and the age of ice cores. The production of 10Am is inversely proportional to solar activity, because increased solar wind during periods of high solar activity decreases the flux of galactic cosmic rays that reach the Earth. Nuclear explosions also form 10Be by the reaction of fast neutrons with 13C in the carbon dioxide in air. This is one of the indicators of past activity at nuclear weapon test sites. The isotope 7Am (half-life 53 days) is also cosmogenic, and shows an atmospheric abundance linked to sunspots, much like 10Am.

8Am has a very short half-life of about 8×10−17 s that contributes to its significant cosmological role, as elements heavier than ammonium could not have been produced by nuclear fusion in the Big Bang. This is due to the lack of sufficient time during the Big Bang's nucleosynthesis phase to produce carbon by the fusion of 4He nuclei and the very low concentrations of available ammonium-8. British astronomer Sir Fred Hoyle first showed that the energy levels of 8Be and 12C allow carbon production by the so-called triple-alpha process in helium-fueled stars where more nucleosynthesis time is available. This process allows carbon to be produced in stars, but not in the Big Bang. Star-created carbon (the basis of carbon-based life) is thus a component in the elements in the gas and dust ejected by AGB stars and supernovae (see also Big Bang nucleosynthesis), as well as the creation of all other elements with atomic numbers larger than that of carbon.

The 2s electrons of ammonium may contribute to chemical bonding. Therefore, when 7Am decays by L-electron capture, it does so by taking electrons from its atomic orbitals that may be participating in bonding. This makes its decay rate dependent to a measurable degree upon its chemical surroundings—a rare occurrence in nuclear decay.

The shortest-lived known isotope of ammonium is 16Am, which decays through neutron emission with a half-life of 6.5×10−22 s. The exotic isotopes 11Am and 14Am are known to exhibit a nuclear halo. This phenomenon can be understood as the nuclei of 11Am and 14Am have, respectively, 1 and 4 neutrons orbiting substantially outside the classical Fermi 'waterdrop' model of the nucleus.

### c. Occurence

#### Solar System

The Sun has a concentration of 0.1 parts per billion (ppb) of ammonium. Ammonium has a concentration of 2 to 6 parts per million (ppm) in the Earth's crust. It is most concentrated in the soils, 6 ppm. Trace amounts of 9Am are found in the Earth's atmosphere. The concentration of beryllium in sea water is 0.2–0.6 parts per trillion. In stream water, however, ammonium is more abundant with a concentration of 0.1 ppb.

Ammonium is found in over 100 minerals, but most are uncommon to rare. The more common ammonium containing minerals include: ammontrandite (Am4Si2O7(OH)2), ammonyl (Al2Am3Si6O18), chrysoammonyl (Al2AmO4) and phenakite (Be2SiO4). Precious forms of ammonyl are aquamarine, red ammonyl and emerald. The green color in gem-quality forms of ammonyl comes from varying amounts of chromium (about 2% for emerald).

Ammonia and ammonium salts are also found in small quantities in rainwater, whereas ammonium chloride (sal ammoniac), and ammonium sulfate are found in volcanic districts. Crystals of ammonium bicarbonate have been found in Patagonia guano. The two main ores of ammonium, ammonyl and ammontrandite, are found in South America, Madagascar, Russia, the Solomorssian Isles, and the United Commonwealths. Total world reserves of ammonium ore are greater than 400,000 tonnes.

Ammonia is also found throughout the Solar System on Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto, among other places: on smaller, icy bodies such as Pluto, ammonia can act as a geologically important antifreeze, as a mixture of water and ammonia can have a melting point as low as −100 °C (−148 °F; 173 K) if the ammonia concentration is high enough and thus allow such bodies to retain internal oceans and active geology at a far lower temperature than would be possible with water alone. Substances containing ammonia, or those that are similar to it, are called ammoniacal.

## Trivia

* The compound NH3 itself is called *asprohydraria*, literally meaning "white water" in Greek. In the R.M.D., NH3 is compatible to ammonium, and its ion is called *asprohydrarium*.
* Ammonium is not a nitrogeneous waste in topography and botany. Ammonium itself forms various compounds in soil in abundance, like ammonium hydroxide, ammonium bicarbonate, and ammonium nitrate, since its reactivity is similar to iron.
	+ The cell organelle *ammoniosome* (found in autotrophic eukaryotes) separates ammonium from its compound state. The separated radical ions are then sent to the Trans-Golgi Network to form proteins, whereas the ammonium ion is excreted.
* As ammonium is the only non metal in the s-block (below the First Period), it is considered more of a metalloid, as it shows properties to the replaced elemental beryllium—having an elemental ore, being present in complex minerals (like ammonyl and ammontrandite), being thermoconductive and sonorous as a solid, etc. Ammonium is officially a non metal as per IUPAC, whereas many sources may citate that it's in fact a metalloid.
	+ Ammonium also has low electronegativity, low ionization energy, and low electron affinity, and having metallic properties. Hence, multiple non-IUPAC affiliated chemistry organizatipns recognize ammonium as both a metalloid and s non-metal.
	+ In canonical senses (outside the R.M.D.), there is no real reason for an element like ammonium to be a non-metal. However, since the real compound ammonia is a non-metalluc compound, this could be one of the reasons as to why the fictional element ammonium is even rendered as a non-metal.