Talk:Phosphorus pentoxide

So It Reacts With Water...
In the Hazards section of the article, it mentions that P4O10 reacts violently with water. It doesn't mention what reaction takes place and what the end products are; it only mentions that it is an exothermic reaction. What is the balanced chemical reaction and its products, and should we include it in the article? Kyoobur9000 (talk) 21:21, 11 October 2012 (UTC)

Melting point
how can the compound boil at a lower temperature (in text) than it melts (in window)? —Preceding unsigned comment added by 194.53.253.50 (talk) 14:57, 17 March 2008 (UTC)

Which states is it in at different temeratures? i.e. when is it a solid, liquid and gas?

Article name
I am concerned about the equation for the reaction of Phosphorus Pentoxide with water. It seems to me that the charg of PO3 should be -3, thus HPO3 is not correct.User:Glander
 * It's fine, PO33- is P(III) (see phosphorous acid) and here the discussion is focused on P(V). Also HPO3 is an idealized formula for partial hydrate.--Smokefoot 17:18, 9 October 2006 (UTC)

I feel that phosphorus pentoxide would be a better name for the article than diphosphorus pentoxide. I've heard the former used exclusively to refer to P4O10. Only on WP have I seen diphosphorus pentoxide used (other than in lists of synonyms)! If we're going to use fully systematic names, then we should use tetraphosphorus decoxide. But as far as I'm aware, the standard practice is to name a compound article after the compound's most common name - which in this case is phosphorus pentoxide.

Google search data:


 * Phosphorus pentoxide: 209,000 hits
 * Diphosphorus pentoxide: 11,000 hits
 * Tetraphosphorus decoxide: 596 hits
 * Tetraphosphorus decaoxide: 459 hits

This is one piece of evidence that suggests a name change might be in order.

I don't know how to change the name of the article myself, so maybe someone else can do it if there is agreement on a name change.

For the meantime, state your support for or rejection of my proposal here.

Ben 11:22, 1 August 2006 (UTC).
 * support for name change to phosphorus pentoxide. I think that all that is needed is "move" it and then check the redirects.

--Smokefoot 04:21, 20 September 2006 (UTC)
 * SupportPyrotec 18:42, 20 September 2006 (UTC)

Moved as per discussion. --Rifleman 82 17:12, 24 September 2006 (UTC)

Formula
I was asked to give the formula for diphosphorus pentoxide, and was marked incorrect when I wrote the molecular formula given on this page, leading to much confusion on my part. When writing a balanced equation for the reaction between this compound and water (forming phosphoric acid), which do I use: the molecular formula or the empirical formula? - Guest User


 * You could use either:


 * P2O5 + 3H2O → 2H3PO4


 * or


 * P4O10 + 6H2O → 4H3PO4


 * I hope this answers your question.


 * Ben 10:34, 10 February 2007 (UTC)

The molecular formula on this Wikipedia page conflicts the molecular formula listed by PubChem.

PubChem states that the molecular formula is "P2O5 or O5P2", searching for "P4O10" is listed as Tetraphosphorus Decoxide --77.162.149.109 (talk) 08:37, 31 May 2021 (UTC)Artur Donaldson, 31st May 2021


 * The article discusses this in the structure section. The compound exists in multiple forms, all of which have the empirical formula P2O5. One of these forms is molecular and has the molecular formula P4O10. The other forms are not molecular but extend effectively infinitely in one or more dimensions so could be described as (P2O5)∞. --Ben (talk) 19:39, 31 May 2021 (UTC)

Error in Properties (right side of the page under the art)
You accidentally flipped the order of the elements from P_4O_10 to O_10P_4 - in the Molecular formula field. —Preceding unsigned comment added by 128.205.48.3 (talk) 02:49, 25 January 2009 (UTC)

Calculation of Hydration Energy
I could not find a direct source for hydration energy, so the number I entered into the article is calculated. The table below documents the calculation. Heats of formation, &Delta;Hf, at 25&deg;C data are taken from Lange's 10th ed.


 * {| align="left"


 * compound and state
 * align="center"|&Delta;Hf
 * P4O10 (amorphous)
 * align="right"|–734.0 kCal
 * H2O (liquid)
 * align="right"|–68.32 kCal
 * 2H2O (liquid)
 * align="right"|–136.64 kCal
 * P4O10 (am) + 2H2O (lq)
 * align="right"|–870.64 kCal
 * HPO3 (crystal)
 * align="right"|–228.2 kCal
 * 4HPO3 (crystal)
 * align="right"|–912.8 kCal
 * net &Delta;H
 * align="right"|–42.24 kCal
 * convert to kJ and round to nearest unit
 * align="right"|–177 kJ
 * }
 * align="right"|–912.8 kCal
 * net &Delta;H
 * align="right"|–42.24 kCal
 * convert to kJ and round to nearest unit
 * align="right"|–177 kJ
 * }
 * align="right"|–177 kJ
 * }

In expressing the format and sign of this &Delta;H in the equation, I used the convention that was used in sulfur trioxide, even though I disagree with it (convention has heat given up by a reaction as negative). So if you change the sign in this equation, please do so also on sulfur trioxide. Karlhahn 12:42, 24 September 2006 (UTC)

Error in Properties (right side of the page under the art)
You accidentally flipped the order of the elements from P_4O_10 to O_10P_4 - in the Molecular formula field. —Preceding unsigned comment added by 128.205.48.3 (talk) 02:47, 25 January 2009 (UTC) The NFPA diamond is wrong as phosphorus pentoxide is non flammable so the "1" on the flammability sale should be changed into "0" — Preceding unsigned comment added by 175.156.192.45 (talk) 13:09, 8 March 2018 (UTC)

More reactions needed
Many reactions of P2O5 are missing: with carbon, basic oxides (like CaO), hydrogen peroxide oxygen, ammonia. Can someone add them? --Siddhant (talk) 16:47, 7 September 2009 (UTC)


 * That is why it is rated as a C-class article and not a B-class (or GA). Pyrotec (talk) 19:22, 7 September 2009 (UTC)

Changed to molecular formula
'formula of P2O5' is ambiguous since it is empirical formula not just formula. I have changed it to a molecular formula so that the reader can grasp the concept more easily —Preceding unsigned comment added by 121.79.5.39 (talk) 06:36, 30 October 2009 (UTC)

Photo
Can we get a photo of the actual chemical? Badagnani (talk) 05:40, 28 November 2009 (UTC)


 * Why? Its just a white powder that forms a glassy surface on exposure to moisture. Pyrotec (talk) 11:54, 29 November 2009 (UTC)

I can provide a photo of the substance in powder form if it would be useful to the article.Woods01 (talk) 05:42, 29 September 2010 (UTC)
 * Please do. Materialscientist (talk) 05:58, 29 September 2010 (UTC)

Not so nonmetallic property of phosphorus?
Density about 3,05 g/cm3 and mp 580 C (about 853 K) and polymeric structure of oxide of pentavalent element are not so nonmetallic properties of phosphorus. Are polymeric forms of this oxide stable at STP? If yes, P behaves here as a metalloid! — Preceding unsigned comment added by 194.29.130.244 (talk) 15:59, 26 November 2013 (UTC)

Rated
Strangely this familiar chemical had no importance assigned. It receives a fair number of hits - as many as some high importance chemicals. Axiosaurus (talk) 11:58, 13 January 2014 (UTC)