Cable theory: Difference between revisions
en>MagnInd →See also: patch clamp |
en>Rjwilmsi m Journal cites, using AWB (9901) |
||
| Line 1: | Line 1: | ||
{{chembox | |||
| Watchedfields = changed | |||
| verifiedrevid = 470455131 | |||
| ImageFile = Gallium-trichloride-from-xtal-2004-3D-balls.png | |||
| ImageSize = | |||
| IUPACName = | |||
| OtherNames = Gallium(III) chloride, Trichlorogallium, Trichlorogallane | |||
| Section1 = {{Chembox Identifiers | |||
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | |||
| ChemSpiderID = 24229 | |||
| UNII_Ref = {{fdacite|correct|FDA}} | |||
| UNII = 4Y6GQD4915 | |||
| InChI = 1/3ClH.Ga/h3*1H;/q;;;+3/p-3 | |||
| SMILES = Cl[Ga](Cl)Cl | |||
| InChIKey = UPWPDUACHOATKO-DFZHHIFOAO | |||
| StdInChI_Ref = {{stdinchicite|correct|chemspider}} | |||
| StdInChI = 1S/3ClH.Ga/h3*1H;/q;;;+3/p-3 | |||
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | |||
| StdInChIKey = UPWPDUACHOATKO-UHFFFAOYSA-K | |||
| CASNo = 13450-90-3 | |||
| CASNo_Ref = {{cascite|correct|CAS}} | |||
| PubChem = 26010 | |||
| RTECS = LW9100000 | |||
}} | |||
| Section2 = {{Chembox Properties | |||
| Formula = GaCl<sub>3</sub> | |||
| Appearance = colorless crystals <br> deliquescent | |||
| Density = 2.47 g/cm<sup>3</sup><br/>2.053 g/cm<sup>3</sup> at melting point | |||
| MeltingPt = 77.9 °C (anhydrous) <br> 44.4 °C (hydrate) | |||
| BoilingPt = 201 °C | |||
| Solubility = very soluble | |||
| SolubleOther = soluble in [[benzene]], [[carbon tetrachloride|CCl<sub>4</sub>]], [[carbon disulfide|CS<sub>4</sub>]] | |||
}} | |||
| Section3 = {{Chembox Hazards | |||
| EUIndex = Not listed | |||
| MainHazards = | |||
| FlashPt = Non-flammable | |||
| RPhrases = | |||
| SPhrases = | |||
| NFPA-H = 3 | |||
| NFPA-F = 0 | |||
| NFPA-R = 1 | |||
| NFPA-O = | |||
| LD50 = 4700 mg/kg (rat, oral) | |||
}} | |||
| Section8 = {{Chembox Related | |||
| OtherAnions = [[Gallium(III) fluoride]]<br/>[[Gallium(III) bromide]]<br/>[[Gallium(III) iodide]] | |||
| OtherCations = [[Aluminium chloride]]<br/>[[Indium(III) chloride]]<br/>[[Thallium(III) chloride]] | |||
}} | |||
}} | |||
'''Gallium trichloride''' is the [[chemical compound]] with the formula GaCl<sub>3</sub>. Solid gallium trichloride exists as a dimer with the formula Ga<sub>2</sub>Cl<sub>6</sub>.<ref>Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.</ref> 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]].<ref>Yamaguchi, M.; Shibasaki, M. Gallium Trichloride" in Encyclopedia of Reagents for Organic Synthesis 2005; John Wiley & Sons. {{DOI|10.1002/047084289X.rn00118u}}</ref> | |||
As a [[Lewis acid]], GaCl<sub>3</sub> is milder than [[aluminium trichloride]]. Gallium(III) is easier to reduce than Al(III), so the chemistry of reduced gallium compounds is more extensive than for aluminium. Ga<sub>2</sub>Cl<sub>4</sub> is known whereas the corresponding Al<sub>2</sub>Cl<sub>4</sub> is not. The coordination chemistry of Ga(III) and Fe(III) are similar, and gallium(III) compounds have been used as diamagnetic analogues of ferric compounds. | |||
==Preparation== | |||
Gallium trichloride can be prepared from the elements, heating [[gallium]] metal in a stream of [[chlorine]], and purifying the product by sublimation under vacuum.<ref>S.C. Wallwork I.J.Worral J.Chem. Soc 1965,1816</ref><ref>Kovar, R. A. "Gallium Trichloride" Inorganic Syntheses, 1977, volume XVII, pp 167-172. ISBN 0-07-044327-0</ref> | |||
:2 Ga + 3 Cl<sub>2</sub> → 2 GaCl<sub>3</sub> | |||
It can also be prepared from the [[gallium oxide]] by heating with [[thionyl chloride]]:<ref>H.Hecht, G.Jander, H.Schlapmann Z. Anorg. Allgem. Chem. Vol.254, p.255 (1947)</ref> | |||
:Ga<sub>2</sub>O<sub>3</sub> + 3 SOCl<sub>2</sub> → 2 GaCl<sub>3</sub> + 3 SO<sub>2</sub> | |||
==Structure== | |||
The dimeric structure involving two chlorine bridging atoms with the gallium atoms essentially tetrahedrally coordinated by chlorine is surprising, as the chlorides of the two members of group 13 above and below gallium, [[aluminium trichloride|AlCl<sub>3</sub>]] and [[indium trichloride|InCl<sub>3</sub>]] both contain 6 coordinate metal atoms in a three dimensional structure. As a consequence of its structure where there are no significant lattice forces, gallium trichloride has the lowest melting point of all of the aluminium, gallium and indium trihalides. The formula of Ga<sub>2</sub>Cl<sub>6</sub> is often written as Ga<sub>2</sub>(μ-Cl)<sub>2</sub>Cl<sub>4</sub>. In the gas phase the dimers dissociate to [[trigonal planar]] monomers. | |||
==Complexes== | |||
[[Gallium]] is the lightest member of Group 13 to have a full ''d'' shell, (gallium has the electronic configuration [[Argon|Ar]] 3''d''10 4''s''2 4''p''1) below the valence electrons that could take part in ''d''-π bonding with ligands. | |||
The low oxidation state of Ga in Ga(III)Cl<sub>3</sub>, along with the low [[electronegativity]] and high [[polarisability]], allow Ga(III)Cl<sub>3</sub> to behave as a "Soft Acid" in terms of the [[HSAB theory]]. The strength of the bonds between gallium halides and ligands have been extensively studied. What emerges is: | |||
*GaCl<sub>3</sub> is a weaker [[Lewis acid]] than AlCl<sub>3</sub> towards N and O donors e.g. pyridine | |||
*GaCl<sub>3</sub> is a stronger [[Lewis acid]] than AlCl<sub>3</sub> towards thioethers e.g. [[dimethyl sulfide]], Me<sub>2</sub>S | |||
With a chloride ion as ligand the tetrahedral GaCl<sub>4</sub><sup><nowiki>−</nowiki></sup> ion is produced, the 6 coordinate GaCl<sub>6</sub><sup>3<nowiki>−</nowiki></sup> cannot be made. Compounds like KGa<sub>2</sub>Cl<sub>7</sub> that have a chloride bridged anion are known<ref>J H von Barner Inorg Chem 1985 24 1686</ref> | |||
In <!--"a liquid solution of" is misleading--> a molten mixture of KCl and GaCl<sub>3</sub>, the following equilibrium exists: | |||
:2 GaCl<sub>4</sub><sup><nowiki>−</nowiki></sup> <math>\overrightarrow{\leftarrow}</math> Ga<sub>2</sub>Cl<sub>7</sub><sup><nowiki>−</nowiki></sup> + Cl<sup><nowiki>−</nowiki></sup> | |||
==Use in detection of solar neutrinos== | |||
110 tons of gallium trichloride solution was used in the [[GALLEX]] experiment performed by [[Laboratori Nazionali del Gran Sasso]] in Italy to detect [[solar neutrino]]s. In this experiment, isotope [[germanium]]-71 was produced and its decay measured.<ref name="crchcp">David R. Lide, ed. ''Handbook of Chemistry and Physics, 85th Edition'', Internet Version 2005. CRC Press, 2005.</ref> | |||
==See also== | |||
*[[Gallium halides]] | |||
==References== | |||
*{{Greenwood&Earnshaw}} | |||
*{{cite web | url = http://www.webelements.com/webelements/elements/text/Ga/key.html | work = WebElements Periodic Table | title = Gallium}} | |||
<references /> | |||
==External links== | |||
* {{cite web | url = http://yosemite.epa.gov/oswer/ceppoehs.nsf/firstaid/13450-90-3?OpenDocument | publisher = [[United States Environmental Protection Agency]] | title = Emergency First Aid Treatment Guide - Gallium Trichloride}} | |||
{{Gallium compounds}} | |||
{{DEFAULTSORT:Gallium Trichloride}} | |||
[[Category:Inorganic compounds]] | |||
[[Category:Gallium compounds]] | |||
[[Category:Chlorides]] | |||
[[Category:Metal halides]] | |||
Revision as of 08:18, 2 February 2014
Template:Chembox Gallium trichloride is the chemical compound with the formula GaCl3. Solid gallium trichloride exists as a dimer with the formula Ga2Cl6.[1] 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.[2]
As a Lewis acid, GaCl3 is milder than aluminium trichloride. Gallium(III) is easier to reduce than Al(III), so the chemistry of reduced gallium compounds is more extensive than for aluminium. Ga2Cl4 is known whereas the corresponding Al2Cl4 is not. The coordination chemistry of Ga(III) and Fe(III) are similar, and gallium(III) compounds have been used as diamagnetic analogues of ferric compounds.
Preparation
Gallium trichloride can be prepared from the elements, heating gallium metal in a stream of chlorine, and purifying the product by sublimation under vacuum.[3][4]
- 2 Ga + 3 Cl2 → 2 GaCl3
It can also be prepared from the gallium oxide by heating with thionyl chloride:[5]
- Ga2O3 + 3 SOCl2 → 2 GaCl3 + 3 SO2
Structure
The dimeric structure involving two chlorine bridging atoms with the gallium atoms essentially tetrahedrally coordinated by chlorine is surprising, as the chlorides of the two members of group 13 above and below gallium, AlCl3 and InCl3 both contain 6 coordinate metal atoms in a three dimensional structure. As a consequence of its structure where there are no significant lattice forces, gallium trichloride has the lowest melting point of all of the aluminium, gallium and indium trihalides. The formula of Ga2Cl6 is often written as Ga2(μ-Cl)2Cl4. In the gas phase the dimers dissociate to trigonal planar monomers.
Complexes
Gallium is the lightest member of Group 13 to have a full d shell, (gallium has the electronic configuration Ar 3d10 4s2 4p1) below the valence electrons that could take part in d-π bonding with ligands. The low oxidation state of Ga in Ga(III)Cl3, along with the low electronegativity and high polarisability, allow Ga(III)Cl3 to behave as a "Soft Acid" in terms of the HSAB theory. The strength of the bonds between gallium halides and ligands have been extensively studied. What emerges is:
- GaCl3 is a weaker Lewis acid than AlCl3 towards N and O donors e.g. pyridine
- GaCl3 is a stronger Lewis acid than AlCl3 towards thioethers e.g. dimethyl sulfide, Me2S
With a chloride ion as ligand the tetrahedral GaCl4− ion is produced, the 6 coordinate GaCl63− cannot be made. Compounds like KGa2Cl7 that have a chloride bridged anion are known[6] In a molten mixture of KCl and GaCl3, the following equilibrium exists:
Use in detection of solar neutrinos
110 tons of gallium trichloride solution was used in the GALLEX experiment performed by Laboratori Nazionali del Gran Sasso in Italy to detect solar neutrinos. In this experiment, isotope germanium-71 was produced and its decay measured.[7]
See also
References
- ↑ Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
- ↑ Yamaguchi, M.; Shibasaki, M. Gallium Trichloride" in Encyclopedia of Reagents for Organic Synthesis 2005; John Wiley & Sons. Electronic Instrument Positions Staff (Standard ) Cameron from Clarence Creek, usually spends time with hobbies and interests which include knotting, property developers in singapore apartment For sale and boomerangs. Has enrolled in a world contiki journey. Is extremely thrilled specifically about visiting .
- ↑ S.C. Wallwork I.J.Worral J.Chem. Soc 1965,1816
- ↑ Kovar, R. A. "Gallium Trichloride" Inorganic Syntheses, 1977, volume XVII, pp 167-172. ISBN 0-07-044327-0
- ↑ H.Hecht, G.Jander, H.Schlapmann Z. Anorg. Allgem. Chem. Vol.254, p.255 (1947)
- ↑ J H von Barner Inorg Chem 1985 24 1686
- ↑ David R. Lide, ed. Handbook of Chemistry and Physics, 85th Edition, Internet Version 2005. CRC Press, 2005.