anhyridien

Anhyridien is a term used in speculative mineralogy to denote a hypothetical hydrogen-bearing mineral phase that forms under high pressure and temperature. The name combines elements of 'anhydrous' and 'hydride', reflecting a lattice in which hydrogen is incorporated without discrete water molecules.

In theoretical models, anhyridien would consist of a dense crystal framework with hydrogen occupying interstitial or normal lattice sites, resulting in a material that remains effectively anhydrous in the sense of lacking water of hydration but contains bonded hydrogen. Predicted properties include anisotropic elasticity and characteristic vibrational spectra that could be detected by infrared or Raman spectroscopy.

Discovery status: The concept arises from first-principles calculations and thermodynamic models. No confirmed natural specimen or laboratory synthesis has been reported as of the latest literature, and stability fields remain hypothetical. Researchers use computational methods to map possible pressure–temperature conditions under which such a phase could exist and to predict its spectroscopic fingerprints.

Occurrence and significance: Anhyridien is envisaged to form in deep Earth settings where hydrogen can diffuse into mineral lattices but free water is unstable. If realized, it would affect models of hydrogen storage in the mantle, mineral physics, and interpretations of seismic data where hydrogen-bearing phases influence elastic properties.

See also: Hydride minerals; High-pressure mineralogy; Anhydrous minerals.