The type IV polymorph of KEu(PO(3))(4)

Area of Science:

• Solid-state chemistry
• Inorganic materials science
• Crystallography

Background:

• Potassium polyphosphates with the general formula A(I)B(III)(PO(3))(4) are known materials.
• Polymorphism, the existence of different crystal structures for the same composition, is common in inorganic compounds.
• Understanding the structural diversity of polyphosphates is crucial for exploring their properties.

Purpose of the Study:

• To synthesize and characterize a new polymorph of potassium europium(III) polyphosphate (KEu(PO(3))(4)).
• To elucidate the crystal structure of this novel monoclinic form.
• To compare its structure with known homologues and understand its structural features.

Main Methods:

• Single crystals of KEu(PO(3))(4) were obtained via solid-state reactions.
• Crystal structure determination was performed (details not specified in abstract, but implied by structural description).
• Structural analysis focused on the arrangement of polyphosphate chains, europium coordination, and potassium ion location.

Main Results:

• A new monoclinic polymorph of KEu(PO(3))(4) was successfully synthesized.
• The structure consists of infinite helical chains of corner-sharing PO(4) tetrahedra (eight tetrahedra per repeat unit).
• A three-dimensional framework is formed by linking these chains with EuO(8) square antiprisms, with K+ ions in pseudo-hexagonal channels.

Conclusions:

• This study reports the second polymorph of KEu(PO(3))(4), classified as a type IV long-chain polyphosphate.
• The determined crystal structure reveals a complex 3D framework built from helical polyphosphate chains and europium coordination polyhedra.
• The compound is isotypic with KEr(PO(3))(4) and KDy(PO(3))(4), highlighting structural similarities among rare-earth analogues.