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Isostructural phase transition in m-carboxyphenylammonium monohydrogenphosphite
El Eulmi Bendeif1, Slimane Dahaoui, Michel François
1Laboratoire de Cristallographie et Modélisation des Matériaux Minéraux et Biologiques LCM3B CNRS UMR 7036, Université Henri Poincaré, Nancy 1, Faculté des Sciences, BP 239, 54506 Vandoeuvre-lès-Nancy CEDEX, France.
Acta Crystallographica. Section B, Structural Science
|November 25, 2005
Summary
m-carboxyphenylammonium monohydrogenphosphite (m-CPAMP) crystals exhibit a reversible phase transition at 246 K. This transition involves a significant unit-cell volume contraction and structural changes investigated via X-ray diffraction and DSC.
Area of Science:
- Crystallography
- Solid-state chemistry
- Materials science
Background:
- m-carboxyphenylammonium monohydrogenphosphite (m-CPAMP) is a crystalline material.
- Understanding phase transitions in such materials is crucial for their applications.
Purpose of the Study:
- To investigate the single-crystal phase transition of m-CPAMP.
- To characterize the structural and thermal properties associated with the transition.
Main Methods:
- Single-crystal X-ray diffraction at variable temperatures (100-320 K).
- Differential scanning calorimetry (DSC) for thermal analysis.
- Analysis of unit-cell parameters and crystal packing.
Main Results:
- A reversible first-order phase transition was observed at 246(2) K with 3.6 K hysteresis.
- The transition involves a 1.77% contraction in unit-cell volume from the higher-temperature phase (HTP) to the lower-temperature phase (LTP).
- Detailed structural analysis at 100 K and 293 K elucidated the packing changes during the transition.
Conclusions:
- The study provides a comprehensive characterization of the m-CPAMP phase transition.
- Structural and thermal data offer insights into the transition mechanism.
- Weak satellite reflections suggest potential complex ordering phenomena.
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