Dichlorine heptoxide


































Dichlorine heptoxide is the chemical compound with the formula Cl2O7. This chlorine oxide is the anhydride of perchloric acid. It is produced by the careful distillation of perchloric acid in the presence of the dehydrating agent phosphorus pentoxide:[1]


2 HClO4 + P4O10 → Cl2O7 + H2P4O11

The chlorine(VII) oxide can be distilled off from the mixture.


It may also be formed by illumination on mixtures of chlorine and ozone.[2] It slowly hydrolyzes back to perchloric acid, which is also hazardous when anhydrous.




Contents





  • 1 Structure


  • 2 Chemistry


  • 3 Safety


  • 4 References




Structure


Cl2O7 is an endergonic molecule, meaning it is intrinsically unstable, decomposing according to.


2 Cl2O7 → 2 Cl2 + 7 O2 (ΔH = 135 kJ/mol)

Cl2O7 is bent with Cl−O−Cl angle of 118.6° giving the molecule C2symmetry. The terminal Cl−O distances are 1.709 Å and the Cl=O distances are 1.405 Å.[1] In this compound, chlorine exists in its highest formal oxidation state of +7, although the bonding in this molecule is significantly covalent.



Chemistry


Dichlorine heptoxide reacts with primary and secondary amines in carbon tetrachloride solution to yield perchloric amides:[3]


2 RNH
2
+ Cl
2
O
7
→ 2 RNHClO
3
+ H
2
O


2 R
2
NH
+ Cl
2
O
7
→ 2 R
2
NClO
3
+ H
2
O


It also reacts with alkenes to give alkyl perchlorates. For example, it reacts with propene in carbon tetrachloride solution to yield isopropyl perchlorate and 1-chloro-2-propyl perchlorate.[4]


Dichlorine heptoxide is a strongly acidic oxide, and in solution it forms an equilibrium with perchloric acid.



Safety


Although it is the most stable chlorine oxide, Cl2O7 is a strong oxidizer as well as an explosive that can be set off with flame or mechanical shock, or by contact with iodine.[5] Nevertheless, it is less strongly oxidising than the other chlorine oxides, and does not attack sulfur, phosphorus, or paper when cold.[1] It has the same effects on the human body as elemental chlorine, and requires the same precautions.[6]



References




  1. ^ abcd Holleman, Arnold F.; Wiberg, Egon (2001). Inorganic chemistry. Translated by Mary Eagleson; William Brewer. San Diego: Academic Press. p. 464. ISBN 0-12-352651-5..mw-parser-output cite.citationfont-style:inherit.mw-parser-output qquotes:"""""""'""'".mw-parser-output code.cs1-codecolor:inherit;background:inherit;border:inherit;padding:inherit.mw-parser-output .cs1-lock-free abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-lock-subscription abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registrationcolor:#555.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration spanborder-bottom:1px dotted;cursor:help.mw-parser-output .cs1-hidden-errordisplay:none;font-size:100%.mw-parser-output .cs1-visible-errorfont-size:100%.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-formatfont-size:95%.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-leftpadding-left:0.2em.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-rightpadding-right:0.2em


  2. ^ Byrns, A. C.; Rollefson, G. K. (1934). "The Formation of Chlorine Heptoxide on Illumination of Mixtures of Chlorine and Ozone". Journal of the American Chemical Society. 56 (5): 1250–1251. doi:10.1021/ja01320a506.


  3. ^ Beard, C. D.; Baum, K. (1974). "Reactions of dichlorine heptoxide with amines". Journal of the American Chemical Society. 96 (10): 3237–3239. doi:10.1021/ja00817a034.


  4. ^ Baum, K. . (1976). "Reactions of dichlorine heptoxide with olefins". The Journal of Organic Chemistry. 41 (9): 1663–1665. doi:10.1021/jo00871a048.


  5. ^ Lewis, Robert Alan (1998). Lewis' dictionary of toxicology. CRC Press. p. 260. ISBN 1-56670-223-2.


  6. ^ Jeanne Mager Stellman, ed. (1998). "Halogens and their compounds". Encyclopaedia of occupational health and safety (4th ed.). International Labour Organization. p. 104.210. ISBN 92-2-109817-6.



Dichlorine heptoxide

Dichlorine heptoxide.svg

Dichlorine-heptoxide-3D-balls.png
Names

IUPAC name
Dichlorine heptoxide

Other names
Chlorine(VII) oxide; Perchloric anhydride; (Perchloryloxy)chlorane trioxide

Identifiers

CAS Number



  • 10294-48-1 ☑Y


3D model (JSmol)


  • Interactive image


ChEBI


  • CHEBI:52356 ☑Y


ChemSpider


  • 109884 ☑Y



PubChem CID


  • 123272





Properties

Chemical formula

Cl2O7

Molar mass
182.901 g/mol
Appearance
colorless liquid

Density
1900 kg m−3

Melting point
−91.57 °C (−132.83 °F; 181.58 K)

Boiling point
82 °C (180 °F; 355 K)

Solubility in water

hydrolyzes to form perchloric acid
Hazards
Main hazards
oxidizer, contact explosive[1]

NFPA 704



Flammability code 0: Will not burn. E.g., waterHealth code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gasReactivity code 3: Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water, or will detonate if severely shocked. E.g., fluorineSpecial hazard OX: Oxidizer. E.g., potassium perchlorateNFPA 704 four-colored diamond

0


3


3

OX



Related compounds

Related compounds


Manganese heptoxide

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).


☑Y verify (what is ☑Y☒N ?)

Infobox references











這個網誌中的熱門文章

How to read a connectionString WITH PROVIDER in .NET Core?

Node.js Script on GitHub Pages or Amazon S3

Museum of Modern and Contemporary Art of Trento and Rovereto