Tetramethylammonium fluoride
Chemical compound
From Wikipedia, the free encyclopedia
Tetramethylammonium fluoride, commonly abbreviated TMAF, is the quaternary ammonium salt with the formula (CH3)4NF. This hygroscopic white solid is a source of “naked fluoride": fluoride ions not complexed with a metal atom. Most other soluble salts of fluoride are in fact bifluorides, HF2–. Historically, there have been two main approaches to prepare tetramethylammonium fluoride: hydrofluoric acid neutralization of tetramethylammonium hydroxide, and salt metathesis between different ammonium salts and inorganic fluoride sources, such as KF or CsF.[1] Because the fluoride anion is extremely basic, the salt slowly reacts with acetonitrile, inducing dimerization to CH3C(NH2)=CHCN, which co-crystallizes.[2]
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| Names | |
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| Preferred IUPAC name
N,N,N-Trimethylmethanaminium fluoride | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.006.154 |
| EC Number |
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PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| C4H12FN | |
| Molar mass | 93.145 g·mol−1 |
| Appearance | white solid |
| Hazards | |
| GHS labelling: | |
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| Warning | |
| H302, H312, H315, H319, H332, H335 | |
| P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P312, P304+P340, P305+P351+P338, P312, P321, P322, P330, P332+P313, P337+P313, P362, P363, P403+P233, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Related salts
- Tetramethylphosphonium fluoride (CH3)4PF forms stable acetonitrile solutions. It is prepared from the ylide and potassium bifluoride:
- (CH3)3P=CH2 + KHF2 → (CH3)4PF + KF
- Gaseous tetramethylphosphonium fluoride exists as the phosphorane but autoionizes in acetonitrile solution.[3] A more elaborate phosphazenium salt ([(CH3)2N)3P]2N+F−) is also known.[4]
- Anhydrous Tetrabutylammonium fluoride has been prepared by the reaction of hexafluorobenzene and tetrabutylammonium cyanide.[5]