Phosphine

Phosphine

Names
IUPAC name Phosphane
Other names Phosphamine Phosphorus trihydride Phosphorated hydrogen
Identifiers
CAS Number	7803-51-2 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:30278 Y
ChemSpider	22814 Y
ECHA InfoCard	100.029.328
EC Number	232-260-8
Gmelin Reference	287
PubChem	24404
RTECS number	SY7525000
UN number	2199
InChI InChI=1S/H3P/h1H3 Y Key: XYFCBTPGUUZFHI-UHFFFAOYSA-N Y InChI=1/H3P/h1H3 Key: XYFCBTPGUUZFHI-UHFFFAOYAP
SMILES P
Properties
Chemical formula	PH3
Molar mass	33.99758 g/mol
Appearance	colorless gas
Odor	faint, fish-like or garlic-like
Density	1.379 g/l, gas (25 °C)
Melting point	−132.8 °C (−207.0 °F; 140.3 K)
Boiling point	−87.7 °C (−125.9 °F; 185.5 K)
Solubility in water	31.2 mg/100 ml (17 °C)
Solubility	soluble in alcohol, ether, CS2 slightly soluble in benzene, chloroform, ethanol
Vapor pressure	41.3 atm (20°C)
Refractive index (nD)	2.144
Viscosity	1.1 x 10−5 Pa s
Structure
Molecular shape	Trigonal pyramidal
Dipole moment	0.58 D
Thermochemistry
Std molar entropy (So298)	210 J·mol−1·K−1
Std enthalpy of formation (ΔfHo298)	5 kJ·mol−1
Hazards
Safety data sheet	ICSC 0694
EU classification (DSD)	F+ (F+) T+ (T+) C (C) N (N)
R-phrases	R12, R17, R26, R34, R50
S-phrases	(S1/2), S28, S36/37, S45, S61, S63
NFPA 704	4 4 2
Flash point	flammable gas
Autoignition temperature	38 °C (100 °F; 311 K) see text
Explosive limits	1.79% – 98%
Lethal dose or concentration (LD, LC):
LD50 (median dose)	3.03 mg/kg (rat, oral)
LC50 (median concentration)	11 ppm (rat, 4 hr)
LCLo (lowest published)	1000 ppm (mammal, 5 min) 270 ppm (mouse, 2 hr) 100 ppm (guinea pig, 4 hr) 50 ppm (cat, 2 hr) 2500 ppm (rabbit, 20 min) 1000 ppm (human, 5 min)
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 0.3 ppm (0.4 mg/m3)
REL (Recommended)	TWA 0.3 ppm (0.4 mg/m3) ST 1 ppm (1 mg/m3)
IDLH (Immediate danger)	50 ppm
Related compounds
Other cations	Ammonia Arsine Stibine Bismuthine
Related compounds	Trimethylphosphine Triphenylphosphine
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Phosphine (IUPAC name: phosphane) is the compound with the chemical formula PH₃. It is a colorless, flammable, toxic gas and pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like garlic or rotting fish, due to the presence of substituted phosphine and diphosphane (P₂H₄). With traces of P₂H₄ present, PH₃ is spontaneously flammable in air, burning with a luminous flame. Phosphines are also a group of organophosphorus compounds with the formula R₃P (R = organic derivative). Organophosphines are important in catalysts where they complex to various metal ions; complexes derived from a chiral phosphine can catalyze reactions to give chiral, enantioenriched products.

Philippe Gengembre (1764-1838), a student of Lavoisier, first obtained phosphine in 1783 by heating phosphorus in an aqueous solution of potash (potassium carbonate).

Perhaps because of its strong association with elemental phosphorus, phosphine was once regarded as a gaseous form of the element, but Lavoisier (1789) recognised it as a combination of phosphorus with hydrogen and described it as phosphure d'hydrogène (phosphide of hydrogen).

In 1844, Paul Thénard, son of the French chemist Louis Jacques Thénard, used a cold trap to separate diphosphine from phosphine that had been generated from calcium phosphide, thereby demonstrating that P₂H₄ is responsible for spontaneous flammability associated with PH₃, and also for the characteristic orange/brown color that can form on surfaces, which is a polymerisation product. He considered diphosphine’s formula to be PH₂, and thus an intermediate between elemental phosphorus, the higher polymers, and phosphine. Calcium phosphide (nominally Ca₃P₂) produces more P₂H₄ than other phosphides because of the preponderance of P-P bonds in the starting material.