Earth-Moon-Earth communication

2015-01-08T07:38:39Z

78.102.9.110: /* Modulation types and frequencies optimal for EME */

35 yr old Deer Farmer Merle Bedell from Port Hawkesbury, has pastimes which includes individuals watching, [http://swachhbharatabhiyan.net/groups/property-diy/ property sale singapore] developers in singapore and kids. In recent years has attended Península Valdés.

Kolmogorov equations (Markov jump process)

2013-08-29T13:29:45Z

78.102.23.61: more understandable indexing

[[File:Quaternary ammonium cation.svg|upright|thumb|[[Quaternary ammonium cation]]. The R's may be the same or different groups. They may also be connected ([[Heterocyclic compound|cyclic]]).]]

In [[chemistry]], a '''quaternary compound''' is a [[cation]] consisting of a central positively charged [[nitrogen group]] atom with four substituents, especially [[organic compound|organic]] ([[alkyl]] and [[aryl]]) groups, discounting [[hydrogen]] atoms.<ref>{{GoldBookRef|title=Onium compounds|file=O04291}}</ref>

The best known quaternary compounds are [[quaternary ammonium cation]]s, having a [[nitrogen]] atom at the centre.<ref>{{GoldBookRef | file = Q05003 | title = quaternary ammonium compounds }}</ref> For example, in the following reaction, the [[nitrogen]] atom is said to be '''quaternized''' as it has gone from 3 to 4 substituents:

:<math>\mathrm{R_3N + RCl \longrightarrow R_4N^+ \ Cl^-}</math>

Other examples include substituted [[phosphonium salt]]s (R4[[Phosphorus|P]]+), substituted [[arsonium salt]]s (R4[[Arsenic|As]]+) like [[arsenobetaine]], as well as some [[arsenic]] containing [[superconductor]]s.<ref>{{cite doi|10.1209/0295-5075/82/57002}}</ref> Substituted [[stibonium salt|stibonium]] (R4[[Antimony|Sb]]+)<ref>{{cite doi|10.1002/zaac.19774350124}}</ref> and [[bismuthonium salt]]s (R4[[Bismuth|Bi]]+) have also been described.<ref>{{cite book|title=Chemistry of arsenic, antimony, and bismuth|author=Nicholas C. Norman|publisher=Springer Netherlands|year=1997|page=316|isbn=0-7514-0389-X|url=http://books.google.at/books?id=vVhpurkfeN4C&pg=PA316&lpg=PA316&dq=tetramethyl+bismuthonium&source=bl&ots=sHfnfzzxWm&sig=e5_UI0j8Ff_W0UDelpUp1zIWsKc&hl=de&ei=FQS3Tp_1DYul-gbqoZWFBg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CB4Q6AEwAA#v=onepage&q=tetramethyl%20bismuthonium&f=false}}</ref>

==See also==
* [[Onium compounds]]

==References==
{{reflist}}

[[Category:Quaternary compounds]]

{{chemistry-stub}}

Talk:Matrix theory

2010-11-26T17:38:57Z

78.102.107.177: /* Split into Matrix Theory (math) and Matrix Theory (film)? */

Hi, everybody! I'm Vietnamese female :). I really like Fantasy Football! My page [http://support.file1.com/entries/35421344-Hostgator-Evaluation Cheap Hosting from Hostgator]

formulasearchengine - User contributions [en]

Earth-Moon-Earth communication

Kolmogorov equations (Markov jump process)

Talk:Matrix theory