Stable Calcium Nitrides at Ambient and High Pressures
Journal Article
·
· Inorganic Chemistry
- Sichuan Univ., Chengdu (China). Inst. of Atomic & Molecular Physics
- Luoyang Normal Univ., Luoyang(China); Beijing Computational Science Research Center, Beijing (China)
- Carnegie Inst. of Washington, Washington, DC (United States). Geophysical Lab.
- Univ. of Saskatchewan, Saskatoon, SK (Canada)
- Univ. of Saskatchewan, Saskatoon, SK (Canada); Canadian Light Sources, Inc., Saskatoon, SK (Canada)
The knowledge of stoichiometries of alkaline-earth metal nitrides, where nitrogen can exist in polynitrogen forms, is of significant interest for understanding nitrogen bonding and its applications in energy storage. For calcium nitrides, there were three known crystalline forms, CaN2, Ca2N, and Ca3N2, at ambient conditions. In the present study, we demonstrated that there are more stable forms of calcium nitrides than what is already known to exist at ambient and high pressures. Using a global structure searching method, we theoretically explored the phase diagram of CaNx and discovered a series of new compounds in this family. In particular, we found a new CaN phase that is thermodynamically stable at ambient conditions, which may be synthesized using CaN2 and Ca2N. Four other stoichiometries, namely, Ca2N3, CaN3, CaN4, and CaN5, were shown to be stable under high pressure. The predicted CaNx compounds contain a rich variety of polynitrogen forms ranging from small molecules (N2, N4, N5, and N6) to extended chains (N∞). Because of the large energy difference between the single and triple nitrogen bonds, dissociation of the CaNx crystals with polynitrogens is expected to be highly exothermic, making them as potential high-energy-density materials.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Energy Frontier Research in Extreme Environments (EFree)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
- Grant/Contract Number:
- SC0001057
- OSTI ID:
- 1388071
- Journal Information:
- Inorganic Chemistry, Journal Name: Inorganic Chemistry Journal Issue: 15 Vol. 55; ISSN 0020-1669
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
catalysis (heterogeneous)
charge transport
energy storage (including batteries and capacitors)
hydrogen and fuel cells
materials and chemistry by design
mesostructured materials
phonons
solar (photovoltaic)
superconductivity
synthesis (novel materials)
thermoelectric
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
catalysis (heterogeneous)
charge transport
energy storage (including batteries and capacitors)
hydrogen and fuel cells
materials and chemistry by design
mesostructured materials
phonons
solar (photovoltaic)
superconductivity
synthesis (novel materials)
thermoelectric