Verbeekite, the Long-Unknown Crystal Structure of Monoclinic PdSe2.
Elisabeth SelbMartina TribusGunter HeymannPublished in: Inorganic chemistry (2017)
Verbeekite, a monoclinic polymorph of PdSe2, was reported for the first time in 2002 by Roberts et al. The mineral has been discovered in the Musonoi Cu-Co-Mn-U mine, Democratic Republic of Congo, and was named after Dr. Théodore Verbeek, the first geoscientist who studied the palladium mineralization there (1955-1967). Until today, the crystal structure of this very rare mineral has been unknown. By syntheses via multianvil high-pressure/high-temperature methods at 11.5 GPa and 1300 °C, synthetic verbeekite could be obtained in a high degree of purity and comparatively good crystal quality, which made it possible to determine the full crystal structure for PdSe2 verbeekite from single-crystal X-ray diffractometer data: I2/a, a = 671.0(2) pm, b = 415.42(8) pm, c = 891.4(2) pm, β = 92.42(3)°, V = 248.24(4) Å3, R1 = 0.0368, wR2 = 0.0907 (all data). In contrast to layered PdS2-type PdSe2, verbeekite exhibits a novel crystal structure type of dichalcogenides of the platinum-group metals with (Se2)2- dimer anions connecting the layers. The possibility of different arrangements of the characteristic (Se2)2- dumbbells is the reason for the various polymorphs of the dichalcogenides, with now five known PdSe2 representatives.
Keyphrases
- crystal structure
- particulate matter
- air pollution
- high temperature
- polycyclic aromatic hydrocarbons
- heavy metals
- electronic health record
- water soluble
- big data
- magnetic resonance
- high resolution
- solid state
- ionic liquid
- reduced graphene oxide
- machine learning
- risk assessment
- quality improvement
- metal organic framework
- room temperature
- computed tomography
- data analysis
- climate change
- electron microscopy