Sodium ammonium tartrate (NAT) is an
organic compound with the formula Na(NH4)[O2CCH(OH)CH(OH)CO2. The salt is derived from
tartaric acid by neutralizing with ammonia and with sodium hydroxide.
Louis Pasteur obtained
enantiopure crystals of the tetrahydrate of NAT, via the process of
spontaneous resolution.[1] His discovery led to increased study of
optical activity, which eventually was shown to have broad implications.[2] Many modification of this salt have been investigated by
X-ray crystallography, including the racemate, which crystallizes as the monohydrate.[3]
Related compounds
NaKO2CCH(OH)CH(OH)CO2(H2O)4, known as
Rochelle salt, was the first ferroelectric material discovered.
References
^L. Pasteur (1849). "Nouvelles recherches de L. Pasteur sur les relations qui peuvent exister entre la forme cristalline, la composition chimique et le phénomène de la polarisation rotatoire". Compt. Rend. 28: 477.
^Brożek, Z.; Mucha, D.; Stadnicka, K. (1994). "X-ray Rietveld structure determination of ammonium Rochelle salt at 120 (Paraelectric phase) and 100 K (Ferroelectric phase)". Acta Crystallographica Section B Structural Science. 50 (4): 465–472.
doi:
10.1107/S0108768194000479.
^Kuroda, Reiko; Mason, Stephen F. (1981). "Crystal structures of dextrorotatory and racemic sodium ammonium tartrate". Journal of the Chemical Society, Dalton Transactions (6): 1268.
doi:
10.1039/DT9810001268.