Germanium difluoride (GeF₂) is a chemical compound of

germanium Germanium is a chemical element; it has Symbol (chemistry), symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid or a nonmetal in the carbon group that is chemically ...

and

fluorine Fluorine is a chemical element; it has Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard temperature and pressure, standard conditions as pale yellow Diatomic molecule, diatomic gas. Fluorine is extre ...

. It is a white solid with a

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilib ...

of 110 °C, and can be produced by reacting germanium tetrafluoride with germanium powder at 150–300 °C.

Structure

Germanium difluoride forms orthorhombic crystals with a

space group In mathematics, physics and chemistry, a space group is the symmetry group of a repeating pattern in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of the pattern that ...

P2₁2₁2₁ (No. 19),

Pearson symbol The Pearson symbol, or Pearson notation, is used in crystallography as a means of describing a crystal structure. It was originated by William Burton Pearson and is used extensively in Pearson's handbook of crystallographic data for intermetallic p ...

oP12, and lattice constants a = 0.4682 nm, b = 0.5178 nm, c = 0.8312 nm, Z = 4 (four structure units per unit cell). Its crystal structure is characterized by strong polymeric chains composed by GeF₃ pyramids. One of the fluorine atom in the pyramid is shared by two neighboring chains, providing a weak link between them. Another, less common crystal form of GeF₂ has tetragonal symmetry with a space group P4₁2₁2 (No. 92),

tP12, and lattice constants a = 0.487 nm, b = 0.6963 nm, c = 0.858 nm.

References

{{Fluorides Fluorides Metal halides Germanium(II) compounds