sodium phosphide

The compound crystallizes in a hexagonal motif, often called the sodium arsenide structure.Beister, H.J.; Syassen, K.; Klein, J."Phase transition of Na₃As under pressure" Zeitschrift für Naturforschung B: Chemical Sciences 1990, volume 45, p1388-p1392. {{doi|10.1515/znb-1990-1007}} Like K₃P, solid Na₃P features pentacoordinate P centers.

The first preparation of Na₃P was first reported in the mid-19th century. French researcher, Alexandre Baudrimont prepared sodium phosphide by treating molten sodium with phosphorus pentachloride.{{cite journal | last1 = Baudrimont | year = 1864 | journal = Annales de chimie et de physique | volume = 2 | page = 13}}

: 8 Na_(l) + PCl₅ → 5 NaCl + Na₃P

Many different routes to Na₃P have been described. Due to its flammability and toxicity, Na₃P (and related salts) is often prepared and used in situ. White phosphorus is reduced by sodium-potassium alloy:{{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}}

: P₄ + 12 Na → 4 Na₃P

Phosphorus reacts with sodium in an autoclave at 150 °C for 5 hours to produce Na₃P.{{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}}

Alternatively the reaction can be conducted at normal pressures but using a temperatures gradient to generate nonvolatile Na_xP phases (x < 3) that then react further with sodium.{{cite journal | 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}} 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.Peterson, D. J. 1967. US Patent No. 3,397,039.

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 PM₃:

:Na₃P + 3 E⁺ → E₃P (E = H, Me₃Si)

The trimethylsilyl derivative is volatile (b.p. 30-35 C @ 0.001 mm Hg) and soluble. It serves as a soluble equivalent to "P³⁻".

Indium phosphide, a semiconductor arises by treating in-situ generated "sodium phosphide" with indium(III) chloride in hot 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:{{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}}

: Na₃P + InCl₃ → InP + 3NaCl

File:Polymer rxn.svg

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 Na₃P on aircraft and trains due to the potential fire and toxic hazards.{{cite web |author= Kenneth L Barbalace |title=Sodium phosphide |publisher=Chemical Database |url=https://environmentalchemistry.com/yogi/chemicals/cn/Sodium%a0phosphide.html}}

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{{Sodium compounds}}

{{Phosphides}}

Category:Phosphides

Category:Sodium compounds