Tellurium tetrafluoride, TeF₄, is a stable, white, hygroscopic crystalline solid and is one of two fluorides of tellurium. The other binary fluoride is tellurium hexafluoride

Tellurium hexafluoride

Tellurium hexafluoride is the oldest known fluoride of tellurium. It is a colorless, highly toxic gas with an extremely unpleasant smell.-Preparation:...

. The widely reported Te₂F₁₀

Ditellurium decafluoride

Ditellurium decafluoride was widely reported in the literature but what was believed to be Te2F10 has been shown to be F5TeOTeF5. An account as to how this error occurred was made by P.M. Watkin....

 has been shown to be F₅TeOTeF₅ There are other tellurium compounds that contain fluorine, but only the two mentioned contain solely tellurium and fluorine. Tellurium difluoride, TeF₂, and ditellurium fluoride, Te₂F are not known.

Preparation

Tellurium tetrafluoride can be prepared by the following reaction:

TeO₂

Tellurium dioxide

Tellurium dioxide is a solid oxide of tellurium. It is encountered in two different forms, the yellow orthorhombic mineral tellurite, β-TeO2, and the synthetic, colourless tetragonal , α-TeO2...

 + 2SF₄

Sulfur tetrafluoride

Sulfur tetrafluoride is the chemical compound with the formula SF4. This species exists as a gas at standard conditions. It is a corrosive species that releases dangerous HF upon exposure to water or moisture...

 → TeF₄ + 2SOF₂

Thionyl fluoride

Thionyl fluoride is the inorganic compound with the formula SOF2. This colourless gas is mainly of theoretical interest, but it is a product of the degradation of sulfur hexafluoride, an insulator in electrical equipment. The molecule adopts a pyramidal structure, with C2v symmetry. The S-O and...

It is also prepared by reacting nitryl fluoride

Nitryl fluoride

Nitryl fluoride, NO2F, is a colourless gas and strong oxidizing agent, which is used as an oxidizer in rocket propellants and as a fluorinating agent. It is a molecular species, not ionic, consistent with its low boiling point...

 with tellurium or from the elements at 0 °C or by reacting selenium tetrafluoride

Selenium tetrafluoride

Selenium tetrafluoride is a chemical compound. It is a colourless liquid that reacts readily with water. It can be used as a fluorinating reagent in organic syntheses and has advantages over sulfur tetrafluoride in that milder conditions can be employed and it is a liquid rather than a gas...

 with tellurium dioxide

Tellurium dioxide

Tellurium dioxide is a solid oxide of tellurium. It is encountered in two different forms, the yellow orthorhombic mineral tellurite, β-TeO2, and the synthetic, colourless tetragonal , α-TeO2...

 at 80 °C.

Fluorine in nitrogen can react with TeCl₂

Tellurium dichloride

Tritellurium dichloride is the inorganic compound with the formula Te3Cl2. It is one of the more stable lower chlorides of tellurium.-Preparation and properties:...

 or TeBr₂

Tellurium dibromide

Ditellurium bromide is the inorganic compound with the formula Te2Br. It is one of the few stable lower bromides of tellurium. Unlike sulfur and selenium, tellurium forms families of polymeric subhalides where the chalcogen/halide ratio is less than 2....

 to form TeF₄. PbF₂

Lead(II) fluoride

Lead fluoride is a chemical compound that is an odorless white solid.Conditions/substances to avoid are: strong oxidizers.-Uses:Lead fluoride is used:* in low melting glasses* in glass coatings to reflect infrared rays...

 will also fluorinate tellurium to TeF₄.

Reactivity

Tellurium tetrafluoride will react with water

Water

Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 or silica and forms tellurium oxides. Copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

, silver

Silver

Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...

, gold

Gold

Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

 or nickel

Nickel

Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...

 will react with tellurium tetrafluoride at 185 °C. It does not react with platinum

Platinum

Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...

. It is soluble in SbF₅

Antimony pentafluoride

Antimony pentafluoride is the inorganic compound with the formula SbF5. This colourless, viscous liquid is a valuable Lewis acid and a component of the superacid fluoroantimonic acid, the strongest known acid...

 and will precipitate out the complex TeF₄SbF₅.

Properties

Tellurium tetrafluoride melts at 130 °C and decomposes to tellurium hexafluoride

Tellurium hexafluoride

Tellurium hexafluoride is the oldest known fluoride of tellurium. It is a colorless, highly toxic gas with an extremely unpleasant smell.-Preparation:...

at 194 °C. In the solid phase it consists of infinite chains of TeF₃F_2/2 in an octahedral geometry. A lone pair of electrons occupies the sixth position.