Thiazyl fluoride, NSF, is a colourless, pungent gas at room temperature and condenses to a pale yellow liquid at 0.4 °C.

[2][3] However, because this synthetic pathway yields numerous side-products, an alternative approach is the reaction of imino(triphenyl)phosphines with sulfur tetrafluoride by cleavage of the bond to form sulfur difluoride imides and triphenyldifluorophosphorane.

For synthesis on a preparative scale, the decomposition of compounds already containing the moiety is commonly used:[5] Lewis acids remove fluoride to afford thiazyl salts:[6] Thiazyl fluoride functions as a ligand in [Re(CO)5NSF]+.

[9] Fluoride gives an adduct: The halogen derivatives XNSF2 (X = F, Cl, Br, I) can be synthesized from reacting Hg(NSF)2 with X2; whereby, ClNSF2 is the most stable compound observed in this series.

[10] At room temperature, thiazyl fluoride undergoes cyclic trimerization via the

The N−S bond length is 1.448 Å, which is short, indicating multiple bonding, and can be represented by the following resonance structures: The NSF molecule has 18 total valence electrons and is isoelectronic to sulfur dioxide.

Thiazyl fluoride adopts Cs-symmetry and has been shown by isotopic substitution to be bent in the ground state.

[11][12] A combination of rotational analysis with Franck-Condon calculations has been applied to study the electronic excitation from the A''