View source for Sodium phosphide

{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 477000388
| ImageFile = Na3AsOffsetLayer.tif
| Name = Sodium phosphide
| OtherNames = sodium phosphide, <br>trisodiophosphine
| Section1 = {{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 55463
| InChI = 1/3Na.P/q3*+1;-3
| InChIKey = FHHBFSHDCCEUKM-UHFFFAOYAE
| SMILES = [Na+].[Na+].[Na+].[P-3]
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/3Na.P/q3*+1;-3
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = FHHBFSHDCCEUKM-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 12058-85-4
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = A360RQX9W2
| PubChem = 61547
| EINECS = 235-031-0
 }}
| Section2 = {{Chembox Properties
| Formula = Na<sub>3</sub>P
| MolarMass = 99.943 g/mol
| Appearance = red crystals
| Solubility = [[hydrolysis]]
| SolubleOther = insoluble in liquid CO<sub>2</sub>
| MeltingPtC = 650
| Density = 1.74 g/cm<sup>3</sup>
}}
| Section3 = {{Chembox Structure
| Coordination = around P 5 near neighbours, trigonal bipyramid <ref name = "Dong">{{cite journal | journal = [[Acta Crystallographica|Acta Crystallographica Section E]] | year = 2005 | volume = 61 | pages = i223–i224 | doi = 10.1107/S1600536805031168 | title = Reinvestigation of Na<sub>3</sub>P based on single-crystal data | author1 = Dong, Y | author2 = Disalvo, F.J | issue = 11| bibcode = 2005AcCrE..61I.223D}}</ref>
| CrystalStruct = [[Hexagonal crystal system|hexagonal]]<br> a = 4.9512 Å<br>c = 8.7874 Å
 }}
| Section8 = {{Chembox Related
| OtherAnions = [[sodium arsenide]]<br />[[sodium nitride]]
| OtherCations = [[aluminium phosphide]]<br />[[lithium phosphide]]<br />[[potassium phosphide]]
 }}
}}
'''Sodium phosphide''' is the [[inorganic compound]] with the formula Na<sub>3</sub>P. It is a black solid. It is often described as [[sodium|Na<sup>+</sup>]] salt of the [[phosphide|P<sup>3−</sup>]] [[anion]].<ref>{{cite journal | journal = [[Materials Research Bulletin]] | year = 2002 | volume = 37 | pages = 1101–1106 | doi = 10.1016/S0025-5408(02)00749-3 | title = A solvothermal synthesis of ultra-fine iron phosphide | author1 = Yunle, G | author2 = Fan, G | author3 = Yiate, Q | author4 = Huagui, Z | author5 = Ziping, Y | issue = 6}}</ref> Na<sub>3</sub>P is a source of the highly reactive phosphide anion. It should not be confused with [[sodium phosphate]], Na<sub>3</sub>PO<sub>4</sub>.

In addition to Na<sub>3</sub>P, five other binary compositions of sodium and phosphorus are known: NaP, Na<sub>3</sub>P<sub>7</sub>, Na<sub>3</sub>P<sub>11</sub>, NaP<sub>7</sub>, and NaP<sub>15</sub>.<ref>''Inorganic Chemistry'', Egon Wiberg, Arnold Frederick Holleman Elsevier 2001 {{ISBN|0-12-352651-5}}</ref>

==Structure and Properties ==
The compound crystallizes in a hexagonal motif, often called the [[sodium arsenide]] structure.<ref>Beister, H.J.; Syassen, K.; Klein, J."Phase transition of Na<sub>3</sub>As under pressure" ''Zeitschrift für Naturforschung B: Chemical Sciences'' 1990, volume 45, p1388-p1392. {{doi|10.1515/znb-1990-1007}}</ref> Like K<sub>3</sub>P, solid Na<sub>3</sub>P features pentacoordinate P centers.<ref name = "Dong"/>

==Preparation==
The first preparation of Na<sub>3</sub>P was first reported in the mid-19th century. French researcher, [[Alexandre Baudrimont]] prepared sodium phosphide by treating molten sodium with [[phosphorus pentachloride]].<ref>{{cite journal | last1 = Baudrimont | year = 1864 | journal = [[Annales de chimie et de physique]] | volume = 2 | page = 13}}</ref>
: 8 [[sodium|Na<sub>(l)</sub>]] + PCl<sub>5</sub> → 5 [[sodium chloride|NaCl]] + Na<sub>3</sub>P

Many different routes to Na<sub>3</sub>P have been described. Due to its flammability and toxicity, Na<sub>3</sub>P (and related salts) is often prepared and used [[in situ]]. White phosphorus is reduced by sodium-potassium alloy:<ref name=InorgSyn>{{cite book | last1 = Becker | first1 = Gerd | last2 = Schmidt | first2 = Helmut | last3 = Uhl | first3 = Gudrun | year = 1990 | title = Inorganic Syntheses | volume = 27 | pages = 243–249 | doi = 10.1002/9780470132586.ch48 | title-link = Tris(trimethylsilyl)phosphine | chapter = Tris(Trimethylsilyl)Phosphine and Lithium Bis(Trimethylsilyl)Phosphide.Bis-(Tetrahydrofuran) | isbn = 9780470132586}}</ref>
: P<sub>4</sub> + 12 Na → 4 Na<sub>3</sub>P

Phosphorus reacts with sodium in an autoclave at 150&nbsp;°C for 5 hours to produce Na<sub>3</sub>P.<ref>{{cite journal | journal = Materials Research Bulletin| year = 2000 | volume = 35 | pages = 675–680 | doi = 10.1016/S0025-5408(00)00263-4 | title = Solvothermal preparation of tin phosphide nanorods | author1 = Xie, Y | author2 = Su, H | author3 = Li, B | author4 = Qian, Y | issue = 5}}</ref>

Alternatively the reaction can be conducted at normal pressures but using a temperatures gradient to generate nonvolatile Na<sub>x</sub>P phases (x < 3) that then react further with sodium.<ref>{{cite journal | journal = [[Inorganic Chemistry (journal)|Inorganic Chemistry]] | year = 2000 | volume = 39 | pages = 3243–3246 | doi = 10.1021/ic000057m | title = Self-Propagating Metathesis Routes to Metastable Group 4 Phosphides | author1 = Jarvis, R. F. | author2 = Jacubinas, R. M. | author3 = Kaner, R. B. | pmid=11196860 | issue = 15}}</ref> In some cases, an electron-transfer agent, such as [[naphthalene]], is used. In such applications, the naphthalene forms the soluble [[sodium naphthalenide]], which reduces the phosphorus.<ref>Peterson, D. J. '''1967'''. US Patent No. 3,397,039.</ref>

==Uses==
Sodium phosphide is a source of the highly reactive and highly basic phosphide anion. The material is insoluble in all solvents but reacts as a slurry with acids and related electrophiles to give derivatives of the type PM<sub>3</sub>:<ref name=InorgSyn/>
:Na<sub>3</sub>P + 3 E<sup>+</sup> → E<sub>3</sub>P (E = H, Me<sub>3</sub>Si)
The [[Tris(trimethylsilyl)phosphine|trimethylsilyl derivative]] is volatile (b.p.&nbsp;30-35 C @ 0.001&nbsp;mm Hg) and soluble. It serves as a soluble equivalent to "P<sup>3−</sup>".

[[Indium phosphide]], a semiconductor arises by treating [[in situ|in-situ]] generated "sodium phosphide" with [[indium(III) chloride]] in hot [[Dimethylformamide|''N,N’''-dimethylformamide]] as solvent. In this process, the phosphide reagent is generated from sodium metal and white phosphorus, whereupon it immediately reacts with the indium salt:<ref>{{cite journal | journal = [[Materials Letters]] | year = 2003 | volume = 57 | pages = 4617–4621 | doi = 10.1016/S0167-577X(03)00371-9 | title = A novel synthesis of indium phosphide nanoparticles | author1 = Khanna, P.K | author2 = Eum, M.-S | author3 = Jun, K.-W | author4 = Baeg, J.-O | author5 = Seok, S. I | issue = 30}}</ref>

: Na<sub>3</sub>P + InCl<sub>3</sub> → InP + 3NaCl

[[File:Polymer rxn.svg|thumb|none|polymerization of propene]]

==Precautions==
Sodium phosphide is highly dangerous releasing toxic [[phosphine]] upon hydrolysis, a process that is so exothermic that fires result. The [[USDOT]] has forbidden the transportation of Na<sub>3</sub>P on aircraft and trains due to the potential fire and toxic hazards.<ref>{{cite web |author= Kenneth L Barbalace |title=Sodium phosphide |publisher=Chemical Database |url=https://environmentalchemistry.com/yogi/chemicals/cn/Sodium%a0phosphide.html}}</ref>

==References==
{{reflist|30em}}

{{Sodium compounds}}
{{Phosphides}}

[[Category:Phosphides]]
[[Category:Sodium compounds]]