Tetra-n-butylammonium iodide

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Tetra-n-butylammonium iodide
Tetrabutylammonium iodide.svg
Preferred IUPAC name
N,N,N-Tributylbutan-1-aminium iodide
Other names
3D model (JSmol)
ECHA InfoCard 100.005.656 Edit this at Wikidata
EC Number
  • 206-220-5
  • InChI=1S/C16H36N.HI/c1-5-9-13-17(14-10-6-2,15-11-7-3)16-12-8-4;/h5-16H2,1-4H3;1H/q+1;/p-1 checkY
  • InChI=1S/C16H36N.HI/c1-5-9-13-17(14-10-6-2,15-11-7-3)16-12-8-4;/h5-16H2,1-4H3;1H/q+1;/p-1
Molar mass 369.3716 g/mol
Appearance White powder
Melting point 147 °C (297 °F; 420 K)
Occupational safety and health (OHS/OSH):
Main hazards
Related compounds
Other anions
Tetrabutylammonium bromide, Tetrabutylammonium chloride, Tetrabutylammonium fluoride, Tetrabutylammonium hydroxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Tetra-n-butylammonium iodide (TBAI) is a quaternary ammonium salt with an iodide counterion. It is used for synthesizing tetra-n-butylammonium triiodide by mixing with iodine.


The solid crystal of tetra-n-butylammonium iodide is in the monoclinic crystal system. It has space group C2/c. The unit cell has dimensions a=14.2806 b=14.1864 c=19.5951 β=111.149. There are eight formulae in the unit cell (Z=8), which has volume 3702.4 Å3.[1]

The enthalpy of formation ΔfH0 of tetra-n-butylammonium iodide is −499 kJ/mol, which is lower than that for the bromide or chloride (−540, −564 kJ/mol).[2]

At lower temperatures with water tetra-n-butylammonium iodide forms a clathrate hydrate.[2] The tetra-n-butylammonium cation is large and hydrophobic. The absolute enthalpy of hydration (from gas phase) is −260 kJ/mol.[2]

The He(I) photoelectron spectrum of tetra-n-butylammonium iodide contains a peak at 11 eV due to the tetra-n-butylammonium cation, and at 7 and 8 eV due to iodide.[3]

See also[edit]


  1. ^ Prukała, Wiesław; Marciniec, Bogdan; Kubicki, Maciej (28 February 2007). "Tetra-n-butylammonium iodide: a space-group revision". Acta Crystallographica Section E. 63 (3): o1464–o1466. doi:10.1107/S1600536807008446.
  2. ^ a b c Nagano, Yatsuhisa; Mizuno, Hideki; Sakiyama, Minoru; Fujiwara, Tadayuki; Kondo, Yasuhiko (March 1991). "Hydration enthalpy of tetra-n-butylammonium ion". The Journal of Physical Chemistry. 95 (6): 2536–2540. doi:10.1021/j100159a079.
  3. ^ Ballard, R.E.; Jones, Jimmy; Sutherland, Elizabeth (December 1984). "He(I) photoelectron spectrum of tetra-N-butylammonium iodide and bromide in solution. The effects of surface activity". Chemical Physics Letters. 112 (4): 310–312. Bibcode:1984CPL...112..310B. doi:10.1016/0009-2614(84)85747-4.