KZn(HP(2)O(7)) x 2H(2)O and KMn(HP(2)O(7)) x -2H(2)O: acidpyrophosphate metallates(II) with layer structures

Area of Science:

• Inorganic Chemistry
• Crystallography
• Materials Science

Background:

• Understanding the structural characteristics of metal pyrophosphates is crucial for developing new materials.
• Isomorphous compounds offer a unique opportunity to study systematic structural variations based on metal ions.

Purpose of the Study:

• To elucidate the detailed crystal structures of potassium zinc hydrogen pyrophosphate dihydrate and potassium manganese hydrogen pyrophosphate dihydrate.
• To investigate the coordination environment of metal ions and the conformation of pyrophosphate anions within these isomorphous structures.

Main Methods:

• Single-crystal X-ray diffraction analysis was employed to determine the atomic arrangements.
• Structural parameters, including bond lengths, bond angles, and coordination geometries, were analyzed.

Main Results:

• The crystal structures reveal isomorphous frameworks composed of acidic pyrophosphate-metallate(II) layers interconnected by potassium ions and hydrogen bonds.
• Zinc (Zn2+) and manganese (Mn2+) ions are octahedrally coordinated by four pyrophosphate oxygen atoms and two water molecules.
• The hydrogen pyrophosphate (HP2O7)3- anions adopt eclipsed conformations, with key atoms lying on mirror planes.

Conclusions:

• The determined crystal structures provide a fundamental understanding of the bonding and structural motifs in these potassium metal hydrogen pyrophosphate hydrates.
• The findings highlight the role of metal ions, pyrophosphate anions, and hydrogen bonding in forming layered inorganic structures.