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Updated: Jun 10, 2026
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Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of Phosphorus(I)
Published on: November 22, 2016
Polymorphism and piezochromicity in the three-dimensional network-based phosphate RbCuPO4
Paul F Henry1, Simon A J Kimber, Dimitri N Argyriou
1MI-1, Helmholtz Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109, Berlin, Germany. paul.henry@helmholtz-berlin.de
Acta Crystallographica. Section B, Structural Science
|July 16, 2010
Summary
Rubidium copper phosphate exhibits two distinct room-temperature forms. Mechanical stress transforms the pale green form (II) into the sky-blue form (I), altering copper coordination and framework structure.
Area of Science:
- Solid-state chemistry
- Crystallography
- Materials science
Background:
- Rubidium copper phosphate (RbCuPO4) exists in multiple crystalline forms.
- Understanding polymorphism is crucial for materials design and application.
Purpose of the Study:
- Investigate the room-temperature polymorphs of RbCuPO4.
- Characterize their structural differences and phase transition mechanisms.
Main Methods:
- Neutron powder diffraction was employed to analyze the crystal structures.
- Mechanical stress (grinding, pelletization) and thermal treatment (quenching) were used to induce phase transitions.
Main Results:
- Two room-temperature polymorphs, (I) and (II), were identified.
- Polymorph (II) transforms to (I) upon grinding or pelletization, with a color change from pale green to sky blue.
- The phase transition involves changes in copper coordination (four- and five-coordinate in II to four-coordinate in I) and a 2.1% volume reduction.
Conclusions:
- The structures of RbCuPO4 polymorphs are based on 3D frameworks with Rb atoms in zeolite-like channels.
- The transition involves a rearrangement of copper polyhedra from dimerized chains in (II) to trimers in (I).
- Structural changes, including copper coordination and framework topology, drive the observed phase transition and associated properties.
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