SeF4 was first described in 1907, but this compound seems to have only recently obtained pure. It is not a particularly easy substance to deal with, because it can attack lubricating oil quickly, and can react slowly with "heat-resistant glass" to form crystalline selenium dioxide, gaseous silicon tetrafluoride and trace boron trifluoride. It will also be instantly hydrolyzed into carbon dioxide by water or moist air.

SeF4 is an inorganic compound. It is a colorless liquid and is easy to react with water. It can be used as a fluorination reagent in organic synthesis (fluorination of alcohol, carboxylic acid or carbonyl compound). Compared with sulfur tetrafluoride, its advantages are that it can be used under mild conditions, and it is liquid rather than gas.

In 1907, Paul Lebeau first reported the synthesis of SeF4. He treated selenium with fluorine:

Se + 2 F2→SeF4

A more easily treated reagent is synthesized by fluorination of selenium dioxide and sulfur tetrafluoride:

SF4 + SeO2→SeF4 + SO2

The intermediate of this reaction is selenoyl fluoride (SeOF2).

Other preparation methods include using chlorine trifluoride fluoride element selenium:

3 Se + 4 ClF3→3 SeF4 + 2 Cl2

The oxidation state of selenium in SeF4 is+4. Its shape in the gas phase is similar to that of SF4, with a seesaw shape. VSEPR theory predicts the pseudo-triangular cone distribution of five electron pairs surrounding selenium atoms. The axial Se-F bond is 177 pm, and the F-Se-F bond angle is 169.2 °. The other two fluorine atoms are connected by a shorter bond (168 pm), and the F-Se-F bond angle is 100.6 °. In low concentration solution, this monomer structure dominates, but at high concentration, evidence shows that the weak correlation between SeF4 molecules leads to distorted octahedral coordination around selenium atoms. There is also a distorted octahedral environment at the center of selenium in solids.

In HF, SeF4 is weak base, weaker than SF4 (Kb=2 X 10 − 2):

SeF4 + HF→SeF3+ + HF2−; (Kb = 4 × 10−4)

Ion adducts containing SeF3+cations form with SbF5, AsF5, NbF5, TaF5 and BF3. It forms SeF5 - anion with cesium fluoride and CsF, which has a square cone structure similar to isoelectronic chlorine pentafluoride, ClF5 and bromine pentafluoride, BrF5. It forms SeF62 − anion with 1,1,3,3,5,5-hexamethylfluoropiperidine or 1,2-dimethylpropyltrimethylammonium fluoride. It has a distorted octahedral shape, which is in contrast to the regular octahedral shape of sec62 −.

SeF4 is a fluoride of selenium. It is used as a fluorination agent in organic synthesis. Selenium is a nonmetallic element with atomic number 34 and chemical symbol Se. Selenium rarely exists as a single substance in nature, and usually exists in sulfide ores, such as pyrite, which partially replaces the sulfur in the ore matrix. It can also be found in silver, copper, lead and nickel minerals. Although a large amount of selenium salt is toxic, trace elements are necessary for the cell function of most animals, forming the active centers of glutathione peroxidase, thioredoxin reductase and three known deiodinase.