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{{Chembox {{Chembox
| Watchedfields = changed
⚫ | ImageFileR1 = Cacodyl-from-xtal-1988-3D-balls.png
| verifiedrevid = 433275081
| ImageSizeR1 = 121
| ImageFile1 = Cacodyl Structural Formula V.3.svg
⚫ | ImageNameR1 = Ball and stick model of cacodyl
| ImageName1 = Structural formula of cacodyl
| ImageFileL1 = Struktur Kakodyl.png
⚫ | ImageFileL2 = Cacodyl-from-xtal-1988-3D-balls.png
| ImageSizeL1 = 121
| ImageNameL1 = Structural formula of cacodyl | ImageNameL2 = Ball and stick model of cacodyl
| ImageFileR2 = Cacodyl-3D-vdW.png
⚫ | IUPACName = Tetramethyldiarsane
⚫ | ImageNameR2 = Space-filling model of cacodyl
⚫ | PIN = Tetramethyldiarsane
| OtherNames = Tetramethyldiarsenic(''As''—''As'')<br /> | OtherNames = Tetramethyldiarsenic(''As''—''As'')<br />
Bis(dimethylarsenic)(''As''—''As'')<br />
Tetramethyldiarsine Tetramethyldiarsine
| Section1 = {{Chembox Identifiers |Section1={{Chembox Identifiers
| CASNo = 471-35-2 | CASNo = 471-35-2
| CASNo_Ref = {{cascite|correct|??}} | CASNo_Ref = {{cascite|correct|??}}
| UNII_Ref = {{fdacite|correct|FDA}}
| PubChem = 79018
| UNII = 11N299093L
| PubChem_Ref = {{Pubchemcite|correct|PubChem}}
| ChemSpiderID = 71351 | PubChem = 79018
| ChemSpiderID = 71351
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| EINECS = 207-440-4
| SMILES = ((C)C)(C)C | EINECS = 207-440-4
| SMILES = ((C)C)(C)C
| SMILES1 = C(C)(C)C | SMILES1 = C(C)(C)C
| StdInChI = 1S/C4H12As2/c1-5(2)6(3)4/h1-4H3 | StdInChI = 1S/C4H12As2/c1-5(2)6(3)4/h1-4H3
| StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| InChI = 1/C4H12As2/c1-5(2)6(3)4/h1-4H3 | InChI = 1/C4H12As2/c1-5(2)6(3)4/h1-4H3
| StdInChIKey = RSKPLCGMBWEANE-UHFFFAOYSA-N | StdInChIKey = RSKPLCGMBWEANE-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| InChIKey = RSKPLCGMBWEANE-UHFFFAOYAG}} | InChIKey = RSKPLCGMBWEANE-UHFFFAOYAG}}
| Section2 = {{Chembox Properties |Section2={{Chembox Properties
| C = 4 | C=4 | H=12 | As=2
| MagSus = -99.9·10<sup>−6</sup> cm<sup>3</sup>/mol
| H = 12
}}
| As = 2
⚫ |Section3={{Chembox Hazards
| ExactMass = 209.937093218 g mol<sup>−1</sup>}}
⚫ | Section3 = {{Chembox Hazards
| MainHazards = | MainHazards =
| FlashPt = | FlashPt =
| Autoignition = }} | AutoignitionPt = }}
}} }}
'''Cacodyl''', '''dicacodyl''', '''tetramethyldiarsine''', '''alkarsine''' or minor part of the "]" (after the French chemist ]) (CH<sub>3</sub>)<sub>2</sub>As—As(CH<sub>3</sub>)<sub>2</sub> is a poisonous oily liquid with a garlicky odor. Cacodyl undergoes spontaneous combustion in dry air. '''Cacodyl''', also known as '''dicacodyl''' or '''tetramethyldiarsine''', (CH<sub>3</sub>)<sub>2</sub>As–As(CH<sub>3</sub>)<sub>2</sub>, is an ] compound that constitutes a major part of "]" (named after the French chemist ]). It is a poisonous oily liquid with an extremely unpleasant garlicky odor. Cacodyl undergoes ] in dry air.<ref>{{cite journal
⚫ | title = Cadet's Fuming Arsenical Liquid and the Cacodyl Compounds of Bunsen
⚫ | first = Dietmar
⚫ | last = Seyferth
⚫ | journal = Organometallics
⚫ | year = 2001
⚫ | volume = 20
⚫ | issue =8
⚫ | pages = 1488&ndash;1498
⚫ | doi = 10.1021/om0101947
⚫ | doi-access = free
⚫ }}</ref>

'''Cacodyl''' is also the name of the ] or ] (CH<sub>3</sub>)<sub>2</sub>As.


==Preparation== ==Preparation==


Cacodyl oxide is prepared by the reaction of ] with ]. A mixture of dicacodyl and cacodyl oxide ((CH<sub>3</sub>)<sub>2</sub>As–O–As(CH<sub>3</sub>)<sub>2</sub>) was first prepared by Cadet by the reaction of ] with ]. A subsequent reduction yields a mixture of several methylated arsenic compounds including dicacodyl.


The global reaction (mass balance) corresponding to the oxide formation is the following:
:4 KCH<sub>3</sub>COO + As<sub>2</sub>O<sub>3</sub> → As<sub>2</sub>(CH<sub>3</sub>)<sub>4</sub>O + 4 K<sub>2</sub>CO<sub>3</sub> + CO<sub>2</sub>


: {{chem2|4 CH3COOK + As2O3 → ((CH3)2As)2O + 2 K2CO3 + 2 CO2}}
A subsequent reduction or ] of the substance under the reaction conditions yields a mixture of several methylated arsenic compounds.


A far better synthesis was developed which started from the dimethyl arsine chloride and dimethyl arsine. A more efficient synthesis was later developed which started from the dimethyl arsine chloride and dimethyl arsine:


: {{chem2|As(CH3)2Cl + As(CH3)2H → As2(CH3)4 + HCl}}
:As(CH<sub>3</sub>)<sub>2</sub>Cl + As(CH<sub>3</sub>)<sub>2</sub>H → As<sub>2</sub>(CH<sub>3</sub>)<sub>4</sub> + HCl


==History== ==History==


] coined the name '''kakodyl''' (later changed to cacodyl) for the dimethylarsinyl radical, (CH<sub>3</sub>)<sub>2</sub>As, from the Greek kakodes (evil-smelling) and hyle (matter).<ref>{{cite journal ] coined the name '''kakodyl''' (later modified to cacodyl in English) for the dimethylarsinyl radical, (CH<sub>3</sub>)<sub>2</sub>As, from the Greek ''κακώδης kakōdēs'' ("evil-smelling") and ὕλη ''hylē'' ("matter").<ref>{{cite journal|author=Berzelius|first=Jöns Jacob|author-link=Jöns Jacob Berzelius|year=1841|title=Kakodyl|url=https://zs.thulb.uni-jena.de/receive/jportal_jparticle_00317596|journal=Jahresberichte über die Fortschritte der Physischen Wissenschaften|volume=20|pages=526–539}}</ref>
| title =
| author = Berzelius, J. J.
| journal = Jahresber.
| year = 1839
| volume = 18
| issue =
| pages = 487
⚫ | doi =
⚫ }}</ref>


It was investigated by ] and ] and is considered one of the earliest ] compounds ever discovered. It was originally made from ] distilled with ] ]. It was investigated by ] and (for over six years) by ] and is considered the earliest ] compound ever discovered (even though arsenic is not a true metal).


In Bunsen's words "''the smell of this body produces instantaneous tingling of the hands and feet, and even giddiness and insensibility...It is remarkable that when one is exposed to the smell of these compounds the tongue becomes covered with a black coating, even when no further evil effects are noticeable''". From it other compounds were made, such as cacodyl fluoride, ], et cetera. One compound, ], was particularly awful. In Bunsen's words "''the smell of this body produces instantaneous tingling of the hands and feet, and even giddiness and insensibility...It is remarkable that when one is exposed to the smell of these compounds the tongue becomes covered with a black coating, even when no further evil effects are noticeable''".


Work on cacodyl led Bunsen to the postulation of ] ]. Work on cacodyl led Bunsen to the postulation of "methyl radicals" as part of the then-current ].


==Use== ==Applications==


Cacodyl was used to prove the radical theory of Berzelius, which resulted in a wide use of cacodyl in research laboratories. After the radical theory was established, the interest in the toxic substance with the literally evil smell decreased. During ] the use of cacodyl as ] was considered, but it was never used in the war. The inorganic chemistry discovered the properties of cacodyl as ligand for transition metals. Cacodyl was used to try to prove the ] of ], which resulted in a wide use of cacodyl in research laboratories. Afterward interest in the toxic, malodorous compound decreased. During ] the use of cacodyl as a ] was considered, but it was never used in the war. Inorganic chemists discovered the properties of cacodyl as a ] for transition metals.

==See also==
* ]
* ]
* ]
* ]
* ]
* ]


==External links==
{{Empty section|date=July 2010}}
==References== ==References==
{{Reflist}} {{Reflist}}
Line 85: Line 98:
| pages = 859–864 | pages = 859–864
| doi = 10.1021/ja01561a020 | doi = 10.1021/ja01561a020
| hdl = 1911/18207
| url = https://scholarship.rice.edu/bitstream/1911/18207/1/3079641.PDF
| hdl-access = free
}} }}
*{{cite journal
⚫ | title = Cadet's Fuming Arsenical Liquid and the Cacodyl Compounds of Bunsen
⚫ | first = Dietmar
⚫ | last = Seyferth
⚫ | journal = Organometallics
⚫ | year = 2001
⚫ | volume = 20
⚫ | issue =8
⚫ | pages = 1488&ndash;1498
⚫ | doi = 10.1021/om0101947
| url = http://pubs.acs.org/cgi-bin/abstract.cgi/orgnd7/2001/20/i08/abs/om0101947.html}}

⚫ ]
]
]


⚫ ]
]
]
]
]
]
]
]
]

Latest revision as of 18:29, 11 September 2024

Cacodyl
Structural formula of cacodyl
Ball and stick model of cacodyl
Ball and stick model of cacodyl
Space-filling model of cacodyl
Space-filling model of cacodyl
Names
Preferred IUPAC name Tetramethyldiarsane
Other names Tetramethyldiarsenic(As—As)

Bis(dimethylarsenic)(As—As)

Tetramethyldiarsine
Identifiers
CAS Number
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.006.766 Edit this at Wikidata
EC Number
  • 207-440-4
PubChem CID
UNII
CompTox Dashboard (EPA)
InChI
  • InChI=1S/C4H12As2/c1-5(2)6(3)4/h1-4H3Key: RSKPLCGMBWEANE-UHFFFAOYSA-N
  • InChI=1/C4H12As2/c1-5(2)6(3)4/h1-4H3Key: RSKPLCGMBWEANE-UHFFFAOYAG
SMILES
  • ((C)C)(C)C
  • C(C)(C)C
Properties
Chemical formula C4H12As2
Molar mass 209.983 g·mol
Magnetic susceptibility (χ) -99.9·10 cm/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). checkY verify (what is  ?) Infobox references
Chemical compound

Cacodyl, also known as dicacodyl or tetramethyldiarsine, (CH3)2As–As(CH3)2, is an organoarsenic compound that constitutes a major part of "Cadet's fuming liquid" (named after the French chemist Louis Claude Cadet de Gassicourt). It is a poisonous oily liquid with an extremely unpleasant garlicky odor. Cacodyl undergoes spontaneous combustion in dry air.

Cacodyl is also the name of the functional group or radical (CH3)2As.

Preparation

A mixture of dicacodyl and cacodyl oxide ((CH3)2As–O–As(CH3)2) was first prepared by Cadet by the reaction of potassium acetate with arsenic trioxide. A subsequent reduction yields a mixture of several methylated arsenic compounds including dicacodyl.

The global reaction (mass balance) corresponding to the oxide formation is the following:

4 CH3COOK + As2O3 → ((CH3)2As)2O + 2 K2CO3 + 2 CO2

A more efficient synthesis was later developed which started from the dimethyl arsine chloride and dimethyl arsine:

As(CH3)2Cl + As(CH3)2H → As2(CH3)4 + HCl

History

Robert Wilhelm Bunsen coined the name kakodyl (later modified to cacodyl in English) for the dimethylarsinyl radical, (CH3)2As, from the Greek κακώδης kakōdēs ("evil-smelling") and ὕλη hylē ("matter").

It was investigated by Edward Frankland and (for over six years) by Robert Bunsen and is considered the earliest organometallic compound ever discovered (even though arsenic is not a true metal).

From it other compounds were made, such as cacodyl fluoride, cacodyl chloride, et cetera. One compound, cacodyl cyanide, was particularly awful. In Bunsen's words "the smell of this body produces instantaneous tingling of the hands and feet, and even giddiness and insensibility...It is remarkable that when one is exposed to the smell of these compounds the tongue becomes covered with a black coating, even when no further evil effects are noticeable".

Work on cacodyl led Bunsen to the postulation of "methyl radicals" as part of the then-current radical theory.

Applications

Cacodyl was used to try to prove the radical theory of Jöns Jacob Berzelius, which resulted in a wide use of cacodyl in research laboratories. Afterward interest in the toxic, malodorous compound decreased. During World War I the use of cacodyl as a chemical weapon was considered, but it was never used in the war. Inorganic chemists discovered the properties of cacodyl as a ligand for transition metals.

See also

References

  1. Seyferth, Dietmar (2001). "Cadet's Fuming Arsenical Liquid and the Cacodyl Compounds of Bunsen". Organometallics. 20 (8): 1488–1498. doi:10.1021/om0101947.
  2. Berzelius, Jöns Jacob (1841). "Kakodyl". Jahresberichte über die Fortschritte der Physischen Wissenschaften. 20: 526–539.
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