The novel refrigerant 2,3,3,3-tetrafluoropropene (HFO-1234yf) is discussed as a replacement for 1,1,1,2-tetrafluoroethane (R-134a) due to its low global warming potential. Although it may therefore have great potential for use on a large scale, no structural data and only a fewvibrational data of the compound are known.We describe low-temperature X-ray structure analysis, vibrational spectra and combustion properties of 2,3,3,3-tetrafluoropropene. The experimental data are compared with the results of theoretical calculations. Furthermore the basic combustion properties have been investigated.