13709-52-9

Usage

Preparation

Hafnium tetrafluoride may be prepared by passing anhydrous hydrogen fluoride over hafnium tetrachloride at 300°C: HfCl4 + 4HF HfF4 + HCl Another method of preparation involves thermal decomposition of ammonium fluorohafnate, (NH4)2 HfF6 [16925-24-9] in the absence of air: (NH4)2 HfF6 HfF4 + 2NH3 + 2HF Also, HfF4 can be prepared by treating metallic hafnium with 40% aqueous HF. The monohydrate formed may be heated at 350°C for several days under a flow of fluorine and nitrogen to yield anhydrous HfF4. Hf + 4HF (aq) → HfF4?H2O + 2H2

Chemical Properties

Off-white powder

Physical properties

White monoclinic crystals; refractive index 1.56; density 7.1 g/cm3; sublimes at 970°C.

Uses

Hafnium(IV) fluoride is used as Vacuum deposition.

Production Methods

Hafnium tetrafluoride is prepared by careful thermal decomposition of ammonium fluorohafniate in an oxygen- free atmosphere or by passing anhydrous hydrogen fluoride over hafnium tetrachloride at 300℃. Direct synthesis from the elements is incomplete because the product merely forms a film on the metal. Ammonium fluorohafniate can be prepared by crystallization from an aqueous hydrofluoric acid solution by adding ammonium fluoride.

InChI:InChI=1/4FH.Hf/h4*1H;/q;;;;+4/p-4

Upstream product

• 7664-39-3 hydrogen fluoride 
• 7782-41-4 fluorine 
• 60816-55-9 hafnium tetrafluoride monohydrate 
• 13709-36-9 xenon difluoride 
• 13499-05-3 hafnium tetrachloride 
• 87118-39-6 NH₄⁽¹⁺⁾*Hf₂F₉^(1-)=NH₄Hf₂F₉ 
• 7783-54-2 nitrogen trifluoride 
• 7784-35-2 arsenic(III) fluoride 

Downstream Products

• 20910-24-1 potassium pentafluorohafnate monohydrate 

Related news

The development of dense scintillating HAFNIUM FLUORIDE (cas 13709-52-9) glasses for the construction of homogeneous calorimeters in particle physics09/27/2019

A study has been made of the properties of fluoride glasses for use in particle calorimeters and a testing regime has been developed. Glasses in a range of compositions have been made and tested in the form of small samples and some, in the form of larger blocks, measuring up to 2×3×14 cm3. Re...detailed

Relevant academic research and scientific papers

Higherature monoclinic α-SrHfF6, and isostructural α-SrZrF6: Associating Hf2F12 bipolyhedra and SrF8 snub disphenoids.

The structure of the higherature monoclinic variety α-SrHfF6 (strontium hafnium hexafluoride) [and of isostructural α-SrZrF6 (strontium zirconium hexafluoride)] associates Hf2F12 bipolyhedra and SrF8 snub disphenoids, forming zigzag twisted [SrF6]n layers. The distribution of the Hf and Sr polyhedra forms a three-dimensional framework which can be related to the family of anion-excess ReO3-related superstructures. α-SrHfF6 corresponds to a new ABX6 type and is compared to the other main families already described. A partial amorphization of this structure is observed in samples quenched from the melt.The crystal structure of α-SrHfF6 corresponds to a new structure type in the ABX6 series. It associates Hf2F12 bipolyhedra and SrF8 snub disphenoids, forming zigzag twisted [SrF6]n layers.

Synthesis and crystal structure of the fluoride-ammine complexes Zr(NH3)F4 and Hf(NH3)F4

Colourless, easily cleavable single crystals of Zr(NH3)F4 and Hf(NH3)F4 without special shape are obtained by oxidation of zirconium and hafnium metal powder with NH4HF2 (molar ratio 1:2) in sealed Monel ampoules at reaction temperatures of 380-450 °C. The two fluoride-ammine complexes crystallize isotypically in the triclinic space group P1 (no. 2) with a = 601.4(1)/597.8(8) pm [Zr(NH3)F4/Hf(NH3)F4], b = 802.8(2)/800.6(12) pm, c = 862.3(2)/860.8(8) pm, α= 106.39(1)/106.19(10)°, β = 104.25(1)/104.51(9)°, γ = 106.83(1)/106.69(11)°, Z = 4. Bicapped trigonal prisms [M(NH3)F7] are connected via edges and corners to form corrugated layers that are held together by hydrogen bonding.

Thermal behaviour of some new hydrazinium fluorometallates

Three new hidrazinium(1+) fluoro complexes, N2H5AsF6, (N2H5)2ZrF6 and (N2H5)2HfF6, were prepared and characterized by means of chemica

The reactions of silver, zirconium, and hafnium fluorides with liquid ammonia: Syntheses and crystal structures of Ag(NH3) 2F·2NH3, [M(NH3)4F 4]·NH3 (M = Zr, Hf), and (N2

By reaction of the tetrafluorides MF4 or the ternary silver fluorides Ag3M2F14 (M = Zr, Hf) with dry liquid ammonia at -40°C, the pentaammoniates [M(NH3)4F 4]·NH3 (1,

Polymorphic and magnetic study of ternary palladium (II) fluorides PdMIVF6 (MIV?Zr, Sn, Hf)

Palladium(II) fluorides with formula PdMIVF6 (MIV≡Zr, Sn, Hf) exhibiting an ordered LiSbF6 type structure (R3ˉ space group) were synthesized. A structural phase transition was detected using microdifferential thermal analysis, microcalorimetry and X-ray diffraction. The thermal dependence of the spontaneous strain was determined. A cubic Fm3ˉm high-temperature form was characterized for PdZrF6 and PdHfF6. The three phases show antiferromagnetic behavior.

Sr3ZrF10, a new type of anion-excess fluorite superstructure. Comparison with Pb3ZrF10 and Pb3HfF10. Influence on defect structure models of M1-xZrxF2+2x fluorite solid solutions

The triclinic P 1ˉ structure of Sr3ZrF10 derives from the fluorite MF2 type by accommodation of the anionic excess (MX2.50) in ZrF8 polyhedra, independent one from another but organized in double columns aligned along [01-1] axis. Contrary to the orthorhombic Cmcm Pb3ZrF10 which also comprises double columns of square antiprisms which are aligned along [001] axis, the successive ZrF8 polyhedra in a column of Sr3ZrF10 take two different orientations in order to decrease the steric constraints resulting from the lower size of Sr2+ compared to Pb2+. In complement, the structure of Pb3ZrF10 is redetermined and the structure of isostructural Pb3HfF10 is refined. A small defect, corresponding to the statistical reorientation of a small proportion of Zr(Hf)F8 polyhedra, in a way similar to that described in Sr3ZrF10, is observed for the first time in both Pb phases but is absent in the isotypic structure of Ba3HfF10 with a higher size Ba2+ cation. The possibility of similar reorientations of the ZrF8 polyhedra in the homologous Pb1-xZrxF2+2x anion excess fluorite solid solution is discussed in relation with the previous models of columnar clusters proposed for this solid solution from neutron diffraction experiments supported by ionic conductivity and 19F NMR measurements of the Pb1-xZrxF2+2x solid solution and of the Pb3ZrF10 ordered superstructure.

Formation and calculations of the simple terminal triplet pnictinidene molecules n÷MF3, P÷MF3, and As÷MF3 (M = Ti, Zr, Hf)

Laser-ablated Ti, Zr, and Hf atoms react with NF3, PF 3, or AsF3 to produce triplet state terminal pnictinidene N÷MF3, P÷MF3, or As÷MF3 molecules, which are trapped in an argon matrix. Prod

New heptafluorozirconates and -hafnates AIBIIZr(Hf) F7 (AI = Rb, Tl; BII = Ca, Cd) - Synthesis, structures, and structural relationships

Four new ABZrF7 heptafluorozirconates (A = Rb, Tl; B = Ca, Cd) and their homologous heptafluorohafnates, all colorless, orthorhombic Cmcm (n°63), Z = 4, have been synthesized by heating stoichiometric mixtures of RbF or TlF, CaF2 or CdF2 and ZrF4 (HfF 4) in sealed platinum tubes at temperature ranging from 550°C (Tl) to 600°C (Rb). The crystal structures of both RbCdZrF7 and TlCdZrF7 have been solved from single-crystal X-rays diffraction data. Rietveld refinements were performed from X-rays powder patterns for RbCaZrF7 and TlCaZrF7. In this series of heptafluorides, both B2+ and Zr4+ cations exhibit a pentagonal bipyramidal 7-coordination. Their structural relationships with other heptafluorozirconates AIBIIZrF7 as well as β-KYb 2F7 are discussed. RbCaZrF7: a = 6.863(1) A, b = 11.130(1) A, c = 8.485(1) A; TlCaZrF7: a = 6.868(1) A b = 11.165(1) A, c = 8.486(1) A; RbCdZrF 7: a = 6.780(1) A, b = 11.054(4) A, c = 8.420(4) A; TlCdZrF7: a = 6.784(3) A b = 11.099(2) A, c = 8.424(9) A.

Thermal behavior of ammonium-bearing zirconium and hafnium hydrofluoride fluoro complexes

Compounds (NH4)4MA3F17 ·2HF (M = Li, Na; A = Zr, Hf) were studied using differential thermal analysis (DTA) and X-ray powder diffraction. It was found that the fluoro complexes studied are dehydrofluorinated in the temperature range 120-230°C, which results in their decomposition and the formation of ammonium- and sodium-(lithium)-bearing fluoro complexes. Copyright

Synthesis and characterization of hydroxylammonium fluorohafnates(IV)

Two new hydroxylammonium compounds, (NH3OH)2HfF6 and (NH3OH)3HfF7 were isolated from the system NH2OH/HF/HfF4/H2O. The compounds were prepared by dissolving