Shattuckite and plancheite: a crystal chemical study

Area of Science:

• Mineralogy
• Crystallography
• Inorganic Chemistry

Background:

• Shattuckite and planchéite are copper silicate minerals with complex structures.
• Understanding their crystal structures is key to their classification and properties.

Purpose of the Study:

• To determine the precise orthorhombic crystal structures of shattuckite and planchéite.
• To elucidate the relationship between their silicate chain arrangements and copper atom associations.

Main Methods:

• Single-crystal X-ray diffraction was used to solve the crystal structures.
• Detailed crystallographic analysis was performed to identify atomic arrangements and bonding.

Main Results:

• The orthorhombic crystal structure of shattuckite, Cu(5)(SiO(3))(4)(OH)(2), was solved.
• The orthorhombic crystal structure of planchéite, Cu(8)(Si(4)O(11))(2)(OH)(4)·H(2)O, was solved.
• Shattuckite exhibits silicate chains analogous to pyroxene, intricately linked with copper atoms.
• Planchéite displays silicate chains similar to amphibole, highlighting structural similarities and differences.

Conclusions:

• The structural solutions confirm the distinct yet related nature of shattuckite and planchéite.
• The findings provide a basis for understanding the chemical and physical properties of these copper silicates.
• The study clarifies the crystallographic relationship between pyroxene- and amphibole-like silicate chains in these minerals.