Diffuse reflectance spectra and polymorphism of mercury (II) iodide

Abstract

Relative diffuse reflectance spectra of microcrystalline HgI2 powder are made between 15000 and 27000 cm−l, at temperatures from ≈ 5 to 530 K. They are transformed into Kubelka‐Munk function spectra. α‐HgI2 shows exciton absorption and emission spectra as well as a strong lu‐ minescence band at 17860 cm−l at ≈ 5 K which shifts to 18700 cm−l at 80 K. Three new low temperature phases are observed when β‐HgI2, is quenched from temperatures above 400 K to 80 or 4.2 K.

Alternating Metastable/Stable Pattern in the Mercuric Iodide Crystal Formation Outside the Ostwald Rule of Stages

“…It exhibits a tetragonal structure that comprises layers of corner-linked HgI 4 tetrahedra, stacked by I•••I contacts. 10,14,15 In this study, we report a system of precipitating mercuric iodide from its precursor salts, mercuric chloride and potassium iodide. The precipitate is produced in a gel media, which forces gradual crystal growth and allows for detailed inspection of every stage of polymorphic transformation.…”

Tetragonal red and yellow HgI2–CdI2 crystals for X- and γ-ray solid-state detectors directionally solidified under argon pressure of 20atm

“…It is well established that tetragonal red a-HgI 2 crystals undergo a structural phase transition to an orthorhombic yellow b-HgI 2 phase in the vicinity of 130 1C [1,2]. The a to b phase transition is destructive yielding highly polycrystalline material.…”