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Beta-Ca3N2, a metastable nitride in the system Ca-N.
Peter Höhn1, Stefan Hoffmann, Jens Hunger
1Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Strasse 40, 01187 Dresden, Germany.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|February 13, 2009
Summary
Calcium nitrides, including beta-calcium nitride (beta-Ca(3)N(2)), exhibit unique structural chemistry. Beta-calcium nitride is a diamagnetic semiconductor that transforms to alpha-calcium nitride at 810 K.
Area of Science:
- Solid-state chemistry
- Materials science
- Inorganic chemistry
Background:
- Calcium nitrides encompass cubic alpha-Ca(3)N(2) and Ca(2)N phases.
- Previously identified phases like "gamma-Ca(3)N(2)" are cyanamide nitrides.
- The metastable beta-Ca(3)N(2) phase is of particular interest.
Purpose of the Study:
- To investigate the synthesis and structural properties of the metastable beta-Ca(3)N(2) phase.
- To characterize the phase transformation of beta-Ca(3)N(2) to alpha-Ca(3)N(2).
- To determine the electronic and magnetic properties of beta-Ca(3)N(2).
Main Methods:
- Synthesis of beta-Ca(3)N(2) via reaction of calcium metal with nitrogen or Ca(2)N with nitrogen.
- X-ray diffraction for crystal structure determination of beta-Ca(3)N(2).
- Magnetic susceptibility and electrical resistivity measurements.
Main Results:
- Beta-Ca(3)N(2) was successfully synthesized and its rhombohedral crystal structure (isotypic to corundum) was determined.
- A phase transformation from beta-Ca(3)N(2) to alpha-Ca(3)N(2) was observed at approximately 810 K.
- Magnetic and electrical measurements indicated that beta-Ca(3)N(2) is a diamagnetic semiconductor.
Conclusions:
- The structural characterization and properties of beta-Ca(3)N(2) were elucidated.
- The phase transition behavior provides insights into calcium nitride polymorphism.
- Beta-Ca(3)N(2) presents potential as a diamagnetic semiconductor material.
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