Gallane

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Gallane
Gallane.svg
Gallane-3D-vdW.png
Gallane-3D-balls.png
Names
IUPAC names
gallane [1]
Other names
trihydridogallium
gallium hydride
hydrogen gallide
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
48991
PubChem CID
  • InChI=1S/Ga.3H
    Key: PHMDYZQXPPOZDG-UHFFFAOYSA-N
  • [GaH3]
Properties
GaH3
Molar mass 72.747 g·mol−1
hydrolyses
Structure
trigonal planar
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Gallane, also systematically named trihydridogallium, is an inorganic compound of gallium with the chemical formula GaH
3
(also written as [GaH
3
]
). It is a photosensitive, colourless gas that cannot be concentrated in pure form. Gallane is both the simplest member of the gallanes, and the prototype of the monogallanes. It has no economic uses, and is only intentionally produced for academic reasons.

Contents

It has been detected as a transient species in the gas phase; [2] also at low temperature (3.5 K) following the reaction of laser ablated gallium atoms and dihydrogen, and more recently in an argon matrix doped with vapour over solid digallane, Ga2H6. [3]

Structure of monomeric GaH3

I.R spectroscopic studies indicate that monomeric GaH3 has a trigonal planar structure. [4] Theoretical Ga-H bond lengths have been calculated as being in the range 155.7 pm to 158.7 pm. [3]

Monomeric GaH3 dimerises in the vapor phase to form Ga2H6, digallane(6) and the enthalpy change associated with the gas phase dissociation reaction Ga2H6 → 2GaH3 has been experimentally estimated as 59 ± 16 kJ mol−1. [5]

Chemical properties

As GaH3 cannot be prepared or isolated readily reactions involving GaH3 either use the dimer, Ga2H6, digallane(6) or adducts of GaH3 for example L·GaH3 where L is a monodentate ligand. [3]

GaH3 adducts

The production of adducts can proceed via the direct reaction of digallane(6) or more often due to the thermal fragility of digallane(6) (which decomposes to gallium metal and hydrogen above -20 °C) using a tetrahydridogallate salt as a starting point (e.g. LiGaH4) or alternatively via ligand displacement from an existing adduct. [3] Examples are:

Ga2H6 + 2 NMe3 → (NMe3)2·GaH3 (-95°C)
LiGaH4 + Me3NHCl → LiCl + H2+ Me3N·GaH3 [3]
Me2NH + Me3N·GaH3 → Me2NH·GaH3 + Me3N [6]

Many adducts have been prepared. There are a number of typical structures with neutral adducts (L = monodentate ligand, L-L is bidentate): [3]

L.GaH3 (1:1 complex with monodentate ligand giving 4 coordinate gallium)
L2·GaH3 (2:1 complex with monodentate ligand giving 5 coordinate gallium)
H3Ga·L-L·GaH3 (1:2 complex with a bidentate ligand with two 4 coordinate gallium atoms)
L'H3Ga·L-L·GaH3L' (complex with monodentate and bidentate ligands with two 5 coordinate gallium atoms)
LGaH2(μ-H)2GaH2L ( 2:2 hydrogen bridged complex)
(-L-LGaH3-)n (1:1 complex with a bidentate ligand forming a polymeric structure)

In comparison to alane (AlH3) with similar ligands, gallane tends to adopt lower coordination numbers. Also whilst N donor ligands form stronger bonds to alumane than phosphines the reverse is typically true for gallane. [3] The monomeric structure of Me3N.GaH3 has been confirmed in both the gas and solid phases. In this regard, the 1:1 adduct contrasts with the corresponding alane complex, Me3N.AlH3 which in the solid is dimeric with bridging hydrogen atoms. [7]

Solute properties

Gaseous gallane is a hydrophilic (non-polar) aprotic solute.[ dubious discuss ] It dissolves in polar compounds such as tetramethylethylenediamine, from which it can be crystallised as gallane—N,N,N′,N′-tetramethylethane-1,2-diamine (1/1). [8] [ verification needed ]

Other chemical reactions

Upon treatment with a standard base, it converts to a metal tetrahydroxygallanuide (the anion Ga(OH)4) and hydrogen gas. With strong bases, it can be deprotonated to give GaH
2
. Reduction of gallane gives gallium metal. Upon treatment with a standard acid, it converts to a gallium(3+) salt and hydrogen gas. Oxidation of gallane gives Ga(OH)3, gallium(III) hydroxide. Unsolvated gallane is in chemical equilibrium with digallane(6), being the dominant species with increasing temperature.[ citation needed ] Due to this equilibrium, gallane and digallane(6) are often considered to be chemically equivalent. Reactions requiring gallane as opposed to digallane(6), must be carried out in solution. Common solvents include tetrahydrofuran, and diethyl ether.

See also

Related Research Articles

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Tetramethylethylenediamine (TMEDA or TEMED) is a chemical compound with the formula (CH3)2NCH2CH2N(CH3)2. This species is derived from ethylenediamine by replacement of the four amine hydrogens with four methyl groups. It is a colorless liquid, although old samples often appear yellow. Its odor is similar to that of rotting fish.

<span class="mw-page-title-main">Gallium(III) bromide</span> Chemical compound

Gallium(III) bromide (GaBr3) is a chemical compound, and one of four gallium trihalides.

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

Aluminium hydride is an inorganic compound with the formula AlH3. Alane and its derivatives are part of a family of common reducing reagents in organic synthesis based around group 13 hydrides. In solution—typically in ethereal solvents such tetrahydrofuran or diethyl ether—aluminium hydride forms complexes with Lewis bases, and reacts selectively with particular organic functional groups, and although it is not a reagent of choice, it can react with carbon-carbon multiple bonds. Given its density, and with hydrogen content on the order of 10% by weight, some forms of alane are, as of 2016, active candidates for storing hydrogen and so for power generation in fuel cell applications, including electric vehicles. As of 2006 it was noted that further research was required to identify an efficient, economical way to reverse the process, regenerating alane from spent aluminium product.

<span class="mw-page-title-main">Gallium(III) chloride</span> Chemical compound

Gallium(III) chloride is an inorganic chemical compound with the formula GaCl3 which forms a monohydrate, GaCl3·H2O. Solid gallium(III) chloride is a deliquescent white solid and exists as a dimer with the formula Ga2Cl6. It is colourless and soluble in virtually all solvents, even alkanes, which is truly unusual for a metal halide. It is the main precursor to most derivatives of gallium and a reagent in organic synthesis.

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

Trimethylgallium, often abbreviated to TMG or TMGa, is the organogallium compound with the formula Ga(CH3)3. It is a colorless, pyrophoric liquid. Unlike trimethylaluminium, TMG adopts a monomeric structure. When examined in detail, the monomeric units are clearly linked by multiple weak Ga---C interactions, reminiscent of the situation for trimethylindium.

There are three sets of Indium halides, the trihalides, the monohalides, and several intermediate halides. In the monohalides the oxidation state of indium is +1 and their proper names are indium(I) fluoride, indium(I) chloride, indium(I) bromide and indium(I) iodide.

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

Digallane is an inorganic compound with the chemical formula GaH2(H)2GaH2. It is the dimer of the monomeric compound gallane. The eventual preparation of the pure compound, reported in 1989, was hailed as a "tour de force." Digallane had been reported as early as 1941 by Wiberg; however, this claim could not be verified by later work by Greenwood and others. This compound is a colorless gas that decomposes above 0 °C.

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

PMDTA (N,N,N,N,N-pentamethyldiethylenetriamine) is an organic compound with the formula [(CH3)2NCH2CH2]2NCH3. PMDTA is a basic, bulky, and flexible, tridentate ligand that is a used in organolithium chemistry. It is a colorless liquid, although impure samples appear yellowish.

<span class="mw-page-title-main">Organogallium chemistry</span> Chemistry of Organogallium compounds

Organogallium chemistry is the chemistry of organometallic compounds containing a carbon to gallium (Ga) chemical bond. Despite their high toxicity, organogallium compounds have some use in organic synthesis. The compound trimethylgallium is of some relevance to MOCVD as a precursor to gallium arsenide via its reaction with arsine at 700 °C:

<span class="mw-page-title-main">Nickel(II) bis(acetylacetonate)</span> Coordination complex

Nickel(II) bis(acetylacetonate) is a coordination complex with the formula [Ni(acac)2]3, where acac is the anion C5H7O2 derived from deprotonation of acetylacetone. It is a dark green paramagnetic solid that is soluble in organic solvents such as toluene. It reacts with water to give the blue-green diaquo complex Ni(acac)2(H2O)2.

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.

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

Indium trihydride is an inorganic compound with the chemical formula. It has been observed in matrix isolation and laser ablation experiments. Gas phase stability has been predicted. The infrared spectrum was obtained in the gas phase by laser ablation of indium in presence of hydrogen gas InH3 is of no practical importance.

Iron(II) hydride, systematically named iron dihydride and poly(dihydridoiron) is solid inorganic compound with the chemical formula (FeH
2
)
n
(also written ([FeH
2
]
)n or FeH
2
). ). It is kinetically unstable at ambient temperature, and as such, little is known about its bulk properties. However, it is known as a black, amorphous powder, which was synthesised for the first time in 2014.

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

Lithium tetrahydridogallate is the inorganic compound with formula LiGaH4. It is a white solid similar to but less thermally robust than lithium aluminium hydride.

<span class="mw-page-title-main">Transition metal pyridine complexes</span>

Transition metal pyridine complexes encompass many coordination complexes that contain pyridine as a ligand. Most examples are mixed-ligand complexes. Many variants of pyridine are also known to coordinate to metal ions, such as the methylpyridines, quinolines, and more complex rings.

Gallium monoiodide is an inorganic gallium compound with the formula GaI or Ga4I4. It is a pale green solid and mixed valent gallium compound, which can contain gallium in the 0, +1, +2, and +3 oxidation states. It is used as a pathway for many gallium-based products. Unlike the gallium(I) halides first crystallographically characterized, gallium monoiodide has a more facile synthesis allowing a synthetic route to many low-valent gallium compounds.

<span class="mw-page-title-main">Transition metal carboxylate complex</span> Class of chemical compounds

Transition metal carboxylate complexes are coordination complexes with carboxylate (RCO2) ligands. Reflecting the diversity of carboxylic acids, the inventory of metal carboxylates is large. Many are useful commercially, and many have attracted intense scholarly scrutiny. Carboxylates exhibit a variety of coordination modes, most common are κ1- (O-monodentate), κ2 (O,O-bidentate), and bridging.

An arsinide, arsanide, dihydridoarsenate(1−) or arsanyl compound is a chemical derivative of arsine, where one hydrogen atom is replaced with a metal or cation. The arsinide ion has formula AsH−2. It can be considered as a ligand with name arsenido or arsanido. Few chemists study arsanyl compounds, as they are both toxic and unstable. The IUPAC names are arsanide and dihydridoarsenate(1−). For the ligand the name is arsanido. The neutral −AsH2 group is termed arsanyl.

Gallium compounds are compounds containing the element gallium. These compounds are found primarily in the +3 oxidation state. The +1 oxidation state is also found in some compounds, although it is less common than it is for gallium's heavier congeners indium and thallium. For example, the very stable GaCl2 contains both gallium(I) and gallium(III) and can be formulated as GaIGaIIICl4; in contrast, the monochloride is unstable above 0 °C, disproportionating into elemental gallium and gallium(III) chloride. Compounds containing Ga–Ga bonds are true gallium(II) compounds, such as GaS (which can be formulated as Ga24+(S2−)2) and the dioxan complex Ga2Cl4(C4H8O2)2. There are also compounds of gallium with negative oxidation states, ranging from -5 to -1, most of these compounds being magnesium gallides (MgxGay).

Gallylenes are a class of gallium species which are electronically neutral and in the +1-oxidation state. This broad definition may include many gallium species, such as oligomeric gallium compounds in which the gallium atoms are coordinated to each other, but these classes of compounds are often referred to as gallanes. In recent literature, the term gallylene has mostly been reserved for low valent gallium species which may have a lone pair, analogous to NHC's or terminal borylenes. They are compounds of academic interest because of their distinctive electronic properties which have been achieved for higher main group elements such as borylenes and carbenes.

References

  1. "Gallane".
  2. The Chemistry of Aluminium, Gallium, Indium and Thallium, Anthony John Downs, 1993, ISBN   075140103X , ISBN   978-0751401035
  3. 1 2 3 4 5 6 7 Aldridge, Simon (2011). "The Chemistry of the Group 13 Metals in the +3 Oxidation State: Simple Inorganic Compounds". In Aldridge, Simon; Downs, Anthony J. (eds.). The Group 13 Metals Aluminium, Gallium, Indium and Thallium: Chemical Patterns and Peculiarities. John Wiley & Sons. ISBN   978-0-470-68191-6.
  4. Pullumbi, P.; Bouteiller, Y.; Manceron, L.; Mijoule, C. (1994). "Aluminium, gallium and indium trihydrides. an IR matrix isolation and ab initio study". Chemical Physics. 185 (1): 25–37. Bibcode:1994CP....185...25P. doi:10.1016/0301-0104(94)00111-1. ISSN   0301-0104.
  5. Downs, Anthony J.; Greene, Tim M.; Johnsen, Emma; Pulham, Colin R.; Robertson, Heather E.; Wann, Derek A. (2010). "The digallane molecule, Ga2H6: experimental update giving an improved structure and estimate of the enthalpy change for the reaction Ga2H6(g) → 2GaH3(g)" (PDF). Dalton Transactions. 39 (24): 5637–42. doi:10.1039/c000694g. hdl: 20.500.11820/f5a6800b-afa9-48c5-ad30-a0f66a7bd46c . ISSN   1477-9226. PMID   20419186.
  6. N.N Greenwood in New Pathways In Inorganic Chemistry, Ed. E.A.V. Ebsworth, A.G. Maddock and A.G. Sharpe. Cambridge University Press, 1968
  7. Brain, Paul, T.; Brown, Helen E.; Downs Anthony J.; Greene Tim M.; Johnsen Emma; Parsons, Simon; Rankin, David W. H.; Smart, Bruce A.; Tang, Christina Y. (1998). "Molecular structure of trimethylamine–gallane, {{Chem|Me|3|N·GaH|3}}: ab initio calculations, gas-phase electron diffraction and single-crystal X-ray diffraction studies". Journal of the Chemical Society, Dalton Transactions (21): 3685–3692. doi:10.1039/A806289G . Retrieved 23 September 2013.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. Atwood, Jerry L.; Bott, Simon G.; Elms, Fiona M.; Jones, Cameron; Raston, Colin L. (October 1991). "Tertiary amine adducts of gallane: gallane-rich [{GaH3}2(TMEDA)] (TMEDA = N,N,N',N'-tetramethylethylenediamine) and thermally robust [GaH3(quinuclidine)]". Inorganic Chemistry. 30 (20): 3792–3793. doi:10.1021/ic00020a002.