Phosphinates or hypophosphites are a class of phosphorus compounds conceptually based on the structure of hypophosphorous acid. IUPAC prefers the term phosphinate in all cases, however in practice hypophosphite is usually used to describe inorganic species (e.g. sodium hypophosphite), while phosphinate typically refers to organophosphorus species.
 Sodium hypophosphite
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3D model (JSmol)
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PubChem CID
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| Properties | |
| H2O2P− | |
| Molar mass | 64.988 g·mol−1 |
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Related compounds
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phosphite; phosphine oxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Hypophosphites
editThe hypophosphite ion is (H
2PO
2)−
. The salts are prepared by heating white phosphorus in warm aqueous alkali e.g. Ca(OH)2:[1]
- P4 + 2 Ca(OH)2 + 4 H2O → 2 Ca(H2PO2)2 + 2 H2
Hypophosphites are reducing agents:[1]
- (H
2PO
2)−
+ 3 OH− → (HPO
3)2−
+ 2 H2O + 2 e−
Hypophosphites are used in electroless nickel plating as the reducing agent to deposit for example Ni metal from Ni salts.[1] The hypophosphite ion is thermodynamically unstable, and disproportionates on heating to phosphine and phosphate salts:
- 2 H
2PO
2−
→ PH3 + HPO
42−
See also
edit- Organophosphinic acid
- Phosphine - PR3
- Phosphine oxide - OPR3
- Phosphite - P(OR)3
- Phosphonate - OP(OR)2R
- Phosphate - OP(OR)3
References
edit- ^ a b c Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 512. ISBN 978-0-08-037941-8.