Misplaced Pages

Potassium oxide: Difference between revisions

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
Browse history interactively
Page 1
Page 2
← Previous editContent deleted Content addedVisualWikitext
Revision as of 07:32, 6 September 2011 editCurb Chain (talk | contribs)18,691 edits WP:HEAD← Previous edit Latest revision as of 09:43, 22 June 2024 edit undoCitation bot (talk | contribs)Bots5,391,743 edits Add: doi, issue. | Use this bot. Report bugs. | #UCB_CommandLine 
(127 intermediate revisions by 92 users not shown)
Line 1: Line 1:
{{chembox {{chembox
| Verifiedfields = changed
| verifiedrevid = 408041297
| Watchedfields = changed
| verifiedrevid = 448711409
| ImageFile = Potassium-oxide-3D-vdW.png | ImageFile = Potassium-oxide-3D-vdW.png
| ImageName = Potassium Oxide spacefilling model
| ImageSize = 200px
| ImageName = Potassium oxide | IUPACName = potassium oxide
| SystematicName = potassium oxidopotassium
| IUPACName = Potassium oxide
| OtherNames = Potassium monoxide | OtherNames = ], dipotassium oxide
| Section1 = {{Chembox Identifiers |Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 12136-45-7
| CASNo = 12136-45-7
| CASNo_Ref = {{cascite|correct|CAS}}
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| UNNumber = 2033
| ChemSpiderID = 23354117
| ChemSpiderID_Comment =
| ChEBI = 88321
| EC_number = 235-227-6
| PubChem = 25520
| UNNumber = 2033
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 58D606078H
| MeSHName = Potassium+oxide
| SMILES = O()
| StdInChI_Ref = {{stdinchicite|changed|chemspider}}
| StdInChI = 1S/2K.O
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
| StdInChIKey = NOTVAPJNGZMVSD-UHFFFAOYSA-N
}} }}
| Section2 = {{Chembox Properties |Section2={{Chembox Properties
| K=2 | O=1
| Formula = K<sub>2</sub>O
| MolarMass = 94.20 g/mol | Appearance = Pale yellow solid
| Odor = Odorless
| Appearance = pale yellow solid
| Density = 2.32 g/cm<sup>3</sup> (20 °C)<ref name=chemister>{{cite web|last = Anatolievich|first = Kiper Ruslan|website=chemister.ru|url = http://chemister.ru/Database/properties-en.php?dbid=1&id=516|title = potassium oxide|access-date = 2014-07-04}}</ref><br> 2.13 g/cm<sup>3</sup> (24 °C)<ref name=crc />
| Density = 2.35 g/cm<sup>3</sup>
| Solubility = Reacts forming ] | Solubility = Reacts<ref name=chemister /> forming ]
| SolubleOther = Soluble in ]<ref name=crc />
| MeltingPt = >350 °C decomp.
| MeltingPtC = 740
| MeltingPt_ref = <ref name=crc>{{CRC90}}</ref>
}} }}
| Section3 = {{Chembox Structure |Section3={{Chembox Structure
| CrystalStruct = ] ], ]<ref name=socacs>{{cite book|page = 25|title = The Structure of Crystals|edition = 2nd|year = 1935|last = Wyckoff|first = Ralph W.G.|publisher = Reinhold Publishing Corp.|work = American Chemical Society}}</ref>
| CrystalStruct = ] (cubic), ]
| SpaceGroup = Fm<u style="text-decoration:overline">3</u>m, No. 225 | SpaceGroup = Fm{{overline|3}}m, No. 225<ref name=socacs />
| Coordination = Tetrahedral (K<sup>+</sup>); cubic (O<sup>2–</sup>) | Coordination = Tetrahedral (K<sup>+</sup>)<br> Cubic (O<sup>2−</sup>)
| LattConst_a = 6.436&nbsp;Å<ref name=socacs />
| LattConst_a =
| LattConst_alpha = | LattConst_alpha = 90
}} }}
| Section4 = {{Chembox Thermochemistry |Section4={{Chembox Thermochemistry
| DeltaHf = −363.17 kJ/mol<ref name=chemister /><ref name=nist>{{nist|name=Dipotassium oxide|id=12136457|accessdate=2014-07-04|mask=FFFF|units=SI}}</ref>
| DeltaHf =
| Entropy = 94.03 J/mol·K<ref name=nist />
| Entropy =
| HeatCapacity = 83.62 J/mol·K<ref name=nist />
| HeatCapacity =
| DeltaGf = −322.1 kJ/mol<ref name=chemister />
}} }}
| Section7 = {{Chembox Hazards |Section7={{Chembox Hazards
| ExternalMSDS = | ExternalSDS =
| MainHazards = Corrosive, reacts violently with water
| EUIndex = Not listed
| NFPA-H = 3
| MainHazards = Corrosive, reacts violently with water
| NFPA-H = | NFPA-F = 0
| NFPA-F = | NFPA-R = 1
| NFPA-R = | NFPA-S = W
| GHSPictograms = {{GHS05}}
| NFPA-O =
| GHSSignalWord = Danger
| FlashPt = Non-flammable
| HPhrases = {{H-phrases|314}}
| PPhrases = {{P-phrases|260|264|280|301+330+331|303+361+353|304+340|305+351+338|310|321|363|405|501}}
}} }}
| Section8 = {{Chembox Related |Section8={{Chembox Related
| OtherAnions = ] | OtherAnions = ]<br>]<br>]<br>]
| OtherCations = ]<br/>]<br/>]<br/>] | OtherCations = ]<br> ]<br> ]<br> ]
| OtherFunctn = ]<br/>] | OtherFunction = ]<br> ]<br>]
| Function = ] ]s | OtherFunction_label = ] ]s
| OtherCpds = ] | OtherCompounds = ]
}} }}
}} }}

'''Potassium oxide''' is an ionic ] of ] and ]. This pale yellow solid, the simplest oxide of potassium, is a rarely encountered, highly reactive species. Some materials of commerce, such as fertilizers and cements, are assayed assuming the percent composition that would be equivalent to K<sub>2</sub>O.
'''Potassium oxide''' (]]) is an ionic ] of ] and ]. It is a ]. This pale yellow solid is the simplest oxide of potassium. It is a highly reactive compound that is rarely encountered. Some industrial materials, such as fertilizers and cements, are assayed assuming the percent composition that would be equivalent to K<sub>2</sub>O.


==Production== ==Production==
Potassium oxide is produced from the reaction of oxygen and potassium; this reaction affords ], K<sub>2</sub>O<sub>2</sub>. Treatment of the peroxide with potassium produces the oxide:<ref>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.</ref> Potassium oxide is produced from the reaction of oxygen and potassium; this reaction affords ], K<sub>2</sub>O<sub>2</sub>. Treatment of the peroxide with potassium produces the oxide:<ref>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. {{ISBN|0-12-352651-5}}.</ref>
: K<sub>2</sub>O<sub>2</sub> + 2 K → 2 K<sub>2</sub>O : <chem>K2O2 + 2 K -> 2 K2O</chem>

Alternatively and more conveniently, K<sub>2</sub>O is synthesized by heating ] with metallic potassium: Alternatively and more conveniently, K<sub>2</sub>O is synthesized by heating ] with metallic potassium:
:<chem>2KNO3 + 10K -> 6K2O + N2 (^)</chem>
:2 KNO<sub>3</sub> + 10 K → 6 K<sub>2</sub>O + N<sub>2</sub>

] cannot be further dehydrated to the oxide.
Other possibility is to heat potassium peroxide at 500&nbsp;°C which decomposes at that temperature giving pure potassium oxide and oxygen.

:<chem>2K2O2 -> 2K2O + O2 (^)</chem>

] cannot be further dehydrated to the oxide but it can react with molten potassium to produce it, releasing ] as a byproduct.

:<chem>2KOH + 2K <=> 2K2O + H2 (^)</chem>


==Properties and reactions== ==Properties and reactions==
K<sub>2</sub>O crystallises in the [[Fluorite structure|
K<sub>2</sub>O crystallises in the antifluorite structure. In this motif the positions of the ]s and ]s are reversed relative to their positions in ], with potassium ions coordinated to 4 oxide ions and oxide ions coordinated to 8 potassium.<ref>{{Citation | title = Gitterstruktur der oxyde, sulfide, selenide und telluride des lithiums, natriums und kaliums | author = ]; Harder, A.; Dauth B. | journal = ] | year = 1934 | volume = 40 | pages = 588–93}}</ref><ref>Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.</ref> K<sub>2</sub>O is a basic oxide and reacts with water violently to produce the caustic ]. It is ] and will absorb water from the atmosphere, initiating this vigorous reaction.
antifluorite structure]]. In this motif the positions of the ]s and ]s are reversed relative to their positions in ], with potassium ions coordinated to 4 oxide ions and oxide ions coordinated to 8 potassium.<ref>{{cite journal|title = Gitterstruktur der oxide, sulfide, selenide und telluride des lithiums, natriums und kaliums|journal = Zeitschrift für Elektrochemie und Angewandte Physikalische Chemie|year = 1934|volume = 40|pages = 588–93|last1 = Zintl|first1 = E.|last2 = Harder|first2 = A.|author3 = Dauth B.| issue=8 | doi=10.1002/bbpc.19340400811 |author-link1 = Eduard Zintl}}</ref><ref>Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. {{ISBN|0-19-855370-6}}.</ref> K<sub>2</sub>O is a basic oxide and reacts with water violently to produce the caustic ]. It is ] and will absorb water from the atmosphere, initiating this vigorous reaction.


==Term use in industry==
==Fertilizers==
The chemical formula K<sub>2</sub>O is used in the N-P-K (nitrogen-phosphorus-potassium) numbers on the labels of ]s. Although K<sub>2</sub>O is the correct formula for potassium oxide, potassium oxide is not used as a fertilizer in these products. Normally, ], ], or ] is used as a fertilizer source for potassium. The percentage of K<sub>2</sub>O given on the label only represents the amount of potassium in the fertilizer if it was in the form of potassium oxide. Potassium oxide is about 83% ] by weight, but ], for instance, is only 52% ] by weight. ] provides less ] than an equal amount of potassium oxide. Thus, if a fertilizer is 30% ] by weight, its standard ] rating, based on potassium oxide, would be only 19%. The chemical formula K<sub>2</sub>O (or simply 'K') is used in several industrial contexts: the ] numbers for ]s, in ], and in ]. Potassium oxide is often not used directly in these products, but the amount of potassium is reported in terms of the K<sub>2</sub>O equivalent for whatever type of ] was used, such as ]. For example, potassium oxide is about 83% ] by weight, while ] is only 52%. ] provides less ] than an equal amount of potassium oxide. Thus, if a fertilizer is 30% ] by weight, its standard ] rating, based on potassium oxide, would be only 18.8%.


==References== ==References==
{{reflist}}
<references />

==External links==
{{Commons category|Potassium oxide}}


{{Potassium compounds}} {{Potassium compounds}}
{{Oxides}}


] ]
] ]
] ]
] ]

]
]
]
]
]
]
]
]
]
]
]
]
]
]
]