Uranium tetrafluoride

Monoclinic

A = 1273 pm b = 1075 pm c = 843 pm β = 126 °

Uranium tetrafluoride

Green crystals

Fixed

6.7 g · cm -3

1036 ° C

1417 ° C

Risk

- ( 1920.0 ± 3.7 ) kJ · mol -1

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Uranium (IV ) fluoride ( UF4 ), usually referred to uranium tetrafluoride is a compound of the elements of uranium and fluorine. It is a green crystalline solid. UF4 is typically an intermediate in the conversion of uranium hexafluoride ( UF6) with both the uranium oxide ( U3O8 and UO2) as well as for uranium metal. It is known as "green salt".

Representation

It is formed by the action of HF on uranium dioxide ( UO2)

Or by reaction of UF6 with hydrogen gas

Very pure uranium (IV ) fluoride can hot uranium ( VI) oxide are obtained by passing dry dichlorodifluoromethane (Freon 12) above 400 ° C.

Properties

Physical Properties

Uranium (IV ) fluoride crystallizes in the monoclinic crystal system, space group C2 / c with lattice parameters a = 1273 pm, b = 1075 pm, c = 843 pm, β = 126 ° and twelve formula units per unit cell.

Chemical Properties

UF4 gradually hydrolyzed with moisture to UO2 and HF. Because of this behavior and the corrosive properties of the forming HF, it is not really suitable for long-term storage.

Safety

UF4 is highly toxic by inhalation and if swallowed. There is also the risk of accumulation in the human body, which affects mainly the liver and kidneys. For aquatic organisms, it is also toxic and may cause long term adverse effects in the aquatic world. As all the uranium compounds it is radioactive. The activity is dependent upon the isotope composition of the uranium.