Nitrogen pentahydride

Last updated
Nitrogen pentahydride
Nitrogen pentahydride possible structure 3D-vdW.png
A possible structure of nitrogen pentahydride according to theory calculations [1]
Names
Other names
Ammonium hydride
Pentahydridonitrogen
Azanediium
Amminedionium
Identifiers
3D model (JSmol)
  • [NH5]
  • [H-].[NH4+]
Properties
H5N
Molar mass 19.047 g·mol−1
Structure
Trigonal bipyramidal molecular geometry (covalent [1] )
0 D (covalent [1] )
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Nitrogen pentahydride, also known as ammonium hydride is a hypothetical compound with the chemical formula NH5. There are two theoretical structures of nitrogen pentahydride. One structure is trigonal bipyramidal molecular geometry type NH5 molecule. Its nitrogen atom and hydrogen atoms are covalently bounded, and its symmetry group is D3h. [1] Another predicted structure of nitrogen pentahydride is an ionic compound, composed of an ammonium ion and a hydride ion (NH4+H−). Until now, no one has synthesized this substance, or proved its existence, and related experiments have not directly observed nitrogen pentahydride. It is only speculated that it may be a reactive intermediate based on reaction products. Theoretical calculations show this molecule is thermodynamically unstable. [4] The reason might be similar to the instability of nitrogen pentafluoride, [5] so the possibility of its existence is low. However, nitrogen pentahydride might exist in special conditions or high pressure. Nitrogen pentahydride was considered for use as a solid rocket fuel for research in 1966. [6]

Contents

Research and attempts

Some studies believe that nitrogen pentahydride may exist in the formation of other metal atoms crystal lattice, such as mercury [7] [8] and lithium. There are also related studies to explore the possibility of a substitution reaction with ammonium halide. [9] There are also attempts to react ammonium and deuterium to produce the pentahydride, however some experiments show that it may only be a reactive intermediate, which will immediately decompose into ammonia and hydrogen, [10] [1] and the same is true for experiments using deuterium. [2] [1] However, all the studies above are only theoretical calculations, the existence of nitrogen pentahydride has not been observed, and this substance has not been shown to exist.

An experimental attempted to do a displacement reaction between ammonium trifluoroacetate and lithium hydride in the molten state, in order to study the possibility of the existence of nitrogen pentahydride: [10]

CF3COONH4 + LiH → CF3COOLi + [NH4H]

In the reaction between ammonium trifluoroacetate and lithium deuteride, the product ammonia contains 85% of ordinary ammonia and 15% of monodeuterated ammonia. The product hydrogen contains 66% of hydrogen deuteride, 21% of hydrogen gas and 13% of deuterium gas. In the product collected using tetradeuterated ammonium trifluoroacetate and lithium hydride, ammonia contains ND3, NHD2 and NH2D, while hydrogen contains 68% of hydrogen deuteride, 18% of hydrogen gas and 14% of deuterium gas. Therefore, it is speculated that the reaction may have two routes: one is to directly decompose into ammonia and hydrogen, the other is to first generate ammonium deuteride reactive intermediates, partly by forming deuterium anions and hydrogen cations to form deuterated hydrogen and ammonia and by the formation of hydride ions or deuterium cations to decompose into hydrogen or deuterium gas. [1]

But it immediately decomposed into hydrogen and ammonia, and it was impossible to prove its existence. Experiments with deuterium still get the same results: [2]

[NH4H] → NH3 + H2

Structure

Possible structures of covalently bounded nitrogen pentahydride Nitrogen pentahydride possible structures.svg
Possible structures of covalently bounded nitrogen pentahydride

Several papers have conducted theoretical calculations on nitrogen pentahydride, and believe that nitrogen pentahydride is unlikely to form ionic crystals of hydride and ammonium ions. However, it is possible that hydrogen is connected to one of the hydrogen atoms of ammonium. [1] It may also be similar to nitrogen pentafluoride, forming a three-center two-electron bond similar to carbonium ions, or those five hydrogen atoms are arranged in a triangular bipyramid structure around the nitrogen atom. [1]

A compound that is similar to nitrogen pentahydride is the theoretical nitrogen pentafluoride. Its structure is assumed to be tetrafluoroammonium fluoride (NF4+F−). [11] Similarly to nitrogen pentahydride, it is a compound of nitrogen and five of the same atom, but nitrogen pentafluoride is also a hypothetical compound, still never synthesized and only theoretical research exist. [12] Other pnictogen pentahydrides are theoretically more stable, such as phosphorus pentahydride (PH4H) which is more stable than nitrogen pentahydride but still unstable to decomposition to phosphine and hydrogen gas. Its organic derivatives (phosphoranes) are more stable, such as stable pentaphenylphosphorus (Ph5P). [13] Other heavier pnictogen pentahydrides are more likely to exist, such as the theoretical arsenic pentahydride. [14] [ better source needed ]

Related Research Articles

<span class="mw-page-title-main">Alkali metal</span> Group of highly reactive chemical elements

The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). Together with hydrogen they constitute group 1, which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in their having very similar characteristic properties. Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. This family of elements is also known as the lithium family after its leading element.

<span class="mw-page-title-main">Nitrogen</span> Chemical element, symbol N and atomic number 7

Nitrogen is a chemical element; it has symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N2, a colorless and odorless diatomic gas. N2 forms about 78% of Earth's atmosphere, making it the most abundant uncombined element in air. Because of the volatility of nitrogen compounds, nitrogen is relatively rare in the solid parts of the Earth.

<span class="mw-page-title-main">Ammonium</span> Chemical compound

The ammonium cation is a positively charged polyatomic ion with the chemical formula NH+4 or [NH4]+. It is formed by the protonation of ammonia. Ammonium is also a general name for positively charged (protonated) substituted amines and quaternary ammonium cations, where one or more hydrogen atoms are replaced by organic or other groups.

<span class="mw-page-title-main">Hydride</span> Molecule with a hydrogen bound to a more electropositive element or group

In chemistry, a hydride is formally the anion of hydrogen (H−), a hydrogen atom with two electrons. The term is applied loosely. At one extreme, all compounds containing covalently bound H atoms are called hydrides: water (H2O) is a hydride of oxygen, ammonia is a hydride of nitrogen, etc. For inorganic chemists, hydrides refer to compounds and ions in which hydrogen is covalently attached to a less electronegative element. In such cases, the H centre has nucleophilic character, which contrasts with the protic character of acids. The hydride anion is very rarely observed.

<span class="mw-page-title-main">Pnictogen</span> Group 15 elements of the periodic table with valency 5

A pnictogen is any of the chemical elements in group 15 of the periodic table. Group 15 is also known as the nitrogen group or nitrogen family. Group 15 consists of the elements nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi), and moscovium (Mc).

<span class="mw-page-title-main">Dinitrogen pentoxide</span> Chemical compound

Dinitrogen pentoxide is the chemical compound with the formula N2O5. It is one of the binary nitrogen oxides, a family of compounds that only contain nitrogen and oxygen. It exists as colourless crystals that sublime slightly above room temperature, yielding a colorless gas.

In chemistry, a hypervalent molecule is a molecule that contains one or more main group elements apparently bearing more than eight electrons in their valence shells. Phosphorus pentachloride, sulfur hexafluoride, chlorine trifluoride, the chlorite ion, and the triiodide ion are examples of hypervalent molecules.

<span class="mw-page-title-main">Lithium hydride</span> Chemical compound

Lithium hydride is an inorganic compound with the formula LiH. This alkali metal hydride is a colorless solid, although commercial samples are grey. Characteristic of a salt-like (ionic) hydride, it has a high melting point, and it is not soluble but reactive with all protic organic solvents. It is soluble and nonreactive with certain molten salts such as lithium fluoride, lithium borohydride, and sodium hydride. With a molar mass of 7.95 g/mol, it is the lightest ionic compound.

<span class="mw-page-title-main">Magic acid</span> Chemical compound

Magic acid (FSO3H·SbF5) is a superacid consisting of a mixture, most commonly in a 1:1 molar ratio, of fluorosulfuric acid (HSO3F) and antimony pentafluoride (SbF5). This conjugate Brønsted–Lewis superacid system was developed in the 1960s by the George Olah lab at Case Western Reserve University, and has been used to stabilize carbocations and hypercoordinated carbonium ions in liquid media. Magic acid and other superacids are also used to catalyze isomerization of saturated hydrocarbons, and have been shown to protonate even weak bases, including methane, xenon, halogens, and molecular hydrogen.

In chemistry, an onium ion is a cation formally obtained by the protonation of mononuclear parent hydride of a pnictogen, chalcogen, or halogen. The oldest-known onium ion, and the namesake for the class, is ammonium, NH+4, the protonated derivative of ammonia, NH3.

The Chichibabin reaction is a method for producing 2-aminopyridine derivatives by the reaction of pyridine with sodium amide. It was reported by Aleksei Chichibabin in 1914. The following is the overall form of the general reaction:

<span class="mw-page-title-main">Positronium hydride</span> Exotic molecule consisting of a hydrogen atom bound to a positronium atom

Positronium hydride, or hydrogen positride is an exotic molecule consisting of a hydrogen atom bound to an exotic atom of positronium. Its formula is PsH. It was predicted to exist in 1951 by A Ore, and subsequently studied theoretically, but was not observed until 1990. R. Pareja, R. Gonzalez from Madrid trapped positronium in hydrogen laden magnesia crystals. The trap was prepared by Yok Chen from the Oak Ridge National Laboratory. In this experiment the positrons were thermalized so that they were not traveling at high speed, and they then reacted with H− ions in the crystal. In 1992 it was created in an experiment done by David M. Schrader and F.M. Jacobsen and others at the Aarhus University in Denmark. The researchers made the positronium hydride molecules by firing intense bursts of positrons into methane, which has the highest density of hydrogen atoms. Upon slowing down, the positrons were captured by ordinary electrons to form positronium atoms which then reacted with hydrogen atoms from the methane.

<span class="mw-page-title-main">Tetrafluoroammonium</span> Chemical compound

The tetrafluoroammonium cation is a positively charged polyatomic ion with chemical formula NF+
4. It is equivalent to the ammonium ion where the hydrogen atoms surrounding the central nitrogen atom have been replaced by fluorine. Tetrafluoroammonium ion is isoelectronic with tetrafluoromethane CF
4, trifluoramine oxide ONF
3 and the tetrafluoroborate BF−
4 anion.

Uranium hydride, also called uranium trihydride (UH3), is an inorganic compound and a hydride of uranium.

Binary compounds of hydrogen are binary chemical compounds containing just hydrogen and one other chemical element. By convention all binary hydrogen compounds are called hydrides even when the hydrogen atom in it is not an anion. These hydrogen compounds can be grouped into several types.

Nitrogen pentafluoride (NF5) is a theoretical compound of nitrogen and fluorine that is hypothesized to exist based on the existence of the pentafluorides of the atoms below nitrogen in the periodic table, such as phosphorus pentafluoride. Theoretical models of the nitrogen pentafluoride molecule are either a trigonal bipyramidal covalently bound molecule with symmetry group D3h, or NF+
4F−, which would be an ionic solid.

Hydrogen chalcogenides are binary compounds of hydrogen with chalcogen atoms. Water, the first chemical compound in this series, contains one oxygen atom and two hydrogen atoms, and is the most common compound on the Earth's surface.

Pnictogen hydrides or hydrogen pnictides are binary compounds of hydrogen with pnictogen atoms covalently bonded to hydrogen.

Carbohydrides are solid compounds in one phase composed of a metal with carbon and hydrogen in the form of carbide and hydride ions. The term carbohydride can also refer to a hydrocarbon.

The inorganic imides are compounds containing an ion composed of nitrogen bonded to hydrogen with formula HN2−. Organic imides have the NH group, and two single or one double covalent bond to other atoms. The imides are related to the inorganic amides (H2N−), the nitrides (N3−) and the nitridohydrides (N3−•H−).

References

  1. 1 2 3 4 5 6 7 8 9 10 Olah, G.A.; Prakash, G.K.S. (2003). Across Conventional Lines: Selected Papers of George A Olah(In 2 Volumes). World Scientific Series in 20th Century Chemistry. p. 759. ISBN   9789814498548. Archived from the original on November 25, 2021.
  2. 1 2 3 Merlet, P. and Koschel, D. and Hack, W. and Haubold, R. and Ohms-Bredemann, U. and Heinrich-Sterzel, C. and Wagner, J. and Keller-Rudek, H. and Schi{\"o}berg, D. and Strametz, C. (2013). N Nitrogen: Compounds with Noble Gases and Hydrogen. Gmelin Handbook of Inorganic and Organometallic Chemistry - 8th edition. Springer Berlin Heidelberg. p. 278. ISBN   9783662063330. Archived from the original on 2017-08-16.{{cite book}}: CS1 maint: multiple names: authors list (link)
  3. ↑ Hisham, Mohamed W. M. and Benson, Sidney W. (1988). "Thermochemistry of inorganic solids. 8. Empirical relations among the enthalpies of formation of different anionic compounds". The Journal of Physical Chemistry. 92 (21): 6107–6112. doi:10.1021/j100332a052.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ↑ Ewig, Carl S.; Van Wazer, John R. (1989). "Ab initio studies of molecular structures and energetics. 3. Pentacoordinated nitrogen NFnH5-n compounds". Journal of the American Chemical Society. 111 (12): 4172–4178. doi:10.1021/ja00194a005.
  5. ↑ Kurzydłowski, Dominik; Zaleski-Ejgierd, Patryk (December 2016). "Hexacoordinated nitrogen(V) stabilized by high pressure". Scientific Reports. 6 (1): 36049. Bibcode:2016NatSR...636049K. doi:10.1038/srep36049. PMC   5093683 . PMID   27808104.
  6. ↑ Sterrett, K. F.; Caron, A. P. (1966). "High pressure chemistry of hydrogenous fuels". Northrop Space Labs. Archived from the original on 2011-08-23. Retrieved 2017-08-21.
  7. ↑ Bard, A.J. and Inzelt, G. and Scholz, F. (2012). Electrochemical Dictionary. Springer Berlin Heidelberg. ISBN   9783642295508. LCCN   2012945766. Archived from the original on 2017-08-16.{{cite book}}: CS1 maint: multiple names: authors list (link)
  8. ↑ Gladyshev, VP; Kovaleva, SV; Khramtsova, NA (2001). "Determination of ammonium by stripping voltammetry". Journal of Analytical Chemistry. Springer. 56 (5): 443–448. doi:10.1023/A:1016627003444. S2CID   195095419.
  9. ↑ Olah, George A.; Donovan, Daniel J.; Shen, Jacob; Klopman, Gilles (1975). "Onium ions. XVI. Hydrogen-deuterium exchange accompanying the cleavage of ammonium (tetradeuterioammonium) trifluoroacetate by lithium deuteride (hydride) indicating SN2 like nucleophilic displacement at quaternary nitrogen through pentacoordinated ammonium hydride". Journal of the American Chemical Society. 97 (12): 3559–3561. doi:10.1021/ja00845a069.
  10. 1 2 Olah, G. A,; Donovan, D. J.;Shen, J.; Klopman, G.(J. Am. Chem. Soc. 97 [1975] 3559/61).
  11. ↑ Goetschel, C. T.; V. A. Campanile; R. M. Curtis; K. R. Loos; C. D. Wagner; J. N. Wilson (July 1972). "Preparation and properties of perfluoroammonium tetrafluoroborate, NF4+BF4-, and possible synthesis of nitrogen pentafluoride". Inorganic Chemistry. 11 (7): 1696–1701. doi:10.1021/ic50113a051.
  12. ↑ Lewars, Errol G. (2008-11-03). Modeling marvels: computational anticipation of novel molecules. Springer. pp. 53–67. ISBN   9781402069734. Archived from the original on 2015-02-12.
  13. ↑ ^ A Guide to Organophosphorus Chemistry Louis D. Quin 2000 John Wiley & Sons ISBN 0-471-31824-8
  14. ↑ "arsorane". CHEBI. Archived from the original on 2017-08-21. Retrieved 2017-08-21.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.