Lithium diphenylphosphide

Lithium diphenylphosphide contains lithium and the organophosphorus anion with the formula (C₆H₅)₂PLi. It is a red, air-sensitive solid that is used in the preparation of diphenylphosphino compounds.

Lithium diphenylphosphide

Names
Preferred IUPAC name Lithium diphenylphosphanide
Identifiers
CAS Number	4541-02-0
3D model (JSmol)	Interactive image
ChemSpider	2719164
PubChem CID	3478053
CompTox Dashboard (EPA)	DTXSID80392839
InChI InChI=1S/C12H10P.Li/c1-3-7-11(8-4-1)13-12-9-5-2-6-10-12;/h1-10H;/q-1;+1 Key: WKUYEGHEUWHKIU-UHFFFAOYSA-N
SMILES [Li+].C1=CC=C(C=C1)[P-]C2=CC=CC=C2
Properties
Chemical formula	C12H10LiP
Molar mass	192.13 g·mol−1
Appearance	pale yellow solid
Solubility in water	Reacts with water
Solubility	Ethers, hydrocarbons
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H312, H314, H332, H410
Precautionary statements	P260, P261, P264, P270, P271, P273, P280, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P310, P312, P321, P322, P330, P363, P391, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis and reactions

The lithium, sodium, and potassium salts are prepared by reduction of chlorodiphenylphosphine,^[1] triphenylphosphine,^[2][3] or tetraphenyldiphosphine with alkali metals (M):

(C₆H₅)₂PCl + 2 M → (C₆H₅)₂PM + MCl

(C₆H₅)₃P + 2 M → (C₆H₅)₂PM + MC₆H₅

(C₆H₅)₄P₂ + 2 M → 2 (C₆H₅)₂PM

They can also be obtained by deprotonation of diphenylphosphine.

With water, the salts convert to diphenylphosphine:^[3]

(C₆H₅)₂PLi + H₂O → (C₆H₅)₂PH + LiOH

With halocarbons, the salts react to give tertiary phosphines:^[4]

(C₆H₅)₂PM + RX → (C₆H₅)₂PR + MX

When treated with metal halides, lithium diphenylphosphide gives transition metal phosphido complexes.

Structure and physical properties

Although treated as salts, alkali diphenylphosphides are highly aggregated in solution. They adopt polymeric structures as solids.

• 
  Part of the polymeric structure of LiPPh₂(Et₂O).^[5]

As an ether complex, the lithium salt is dark red.^[6]

Related compounds

• Sodium diphenylphosphide (CAS RN 4376-01-6)
• Potassium diphenylphosphide (CAS RN 15475-27-1)