The Chevrel phase HgMo(6)S(8)

Area of Science:

• Solid-state chemistry
• Inorganic materials science
• Crystallography

Background:

• Molybdenum-sulfide clusters are known for their unique structural and electronic properties.
• Investigating the incorporation of guest atoms into these cluster frameworks is crucial for materials discovery.
• Mercury-containing molybdenum sulfides represent a less explored area within this class of materials.

Purpose of the Study:

• To elucidate the crystal structure of mercury(II) hexa-molybdenum octa-sulfide (HgMo(6)S(8)).
• To understand the coordination and bonding of mercury cations within the Mo(6)S(8) framework.
• To determine the precise stoichiometry of the synthesized compound.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the atomic arrangement.
• Crystallographic refinement was performed to optimize the structural model and determine atom occupancies.
• Symmetry analysis was used to describe the positions and bonding of the mercury and sulfur atoms.

Main Results:

• The crystal structure is characterized by (Mo(6)S(8))S(6) cluster units linked by inter-unit Mo-S bonds.
• Mercury cations (Hg(2+)) are located in voids between clusters and form covalent bonds with two sulfur atoms.
• Refinement of the mercury occupancy factor yielded the composition Hg(0.973(3))Mo(6)S(8).

Conclusions:

• HgMo(6)S(8) exhibits a distinct crystal structure based on interconnected Mo(6)S(8) clusters.
• The mercury atoms occupy specific crystallographic sites, demonstrating covalent interactions with sulfur.
• The determined stoichiometry provides precise information about the composition of this mercury-molybdenum sulfide material.