Theoretical study of the gas-phase structure, thermochemistry, and decomposition mechanisms of NH{sub 4}NO{sub 2} and NH{sub 4}N(NO{sub 2}){sub 2}

Journal Article · Thu May 04 00:00:00 EDT 1995 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/j100018a015· OSTI ID:50484

Mebel, A M; Lin, M C; Morokuma, K ^[1]; Melius, C F ^[2]

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1. Emory Univ., Atlanta, GA (United States)
2. Sandia National Lab., Livermore, CA (United States)

The structures, energetics, and decomposition mechanisms of gaseous ammonium nitrite (NH{sub 4}NO{sub 2}) and ammonium dinitramide [ADN, NH{sub 4}N(NO{sub 2}){sub 2}] have been studied theoretically by different ab initio molecular orbital approaches. In the gas phase, both species have the structures of molecular complexes, [NH{sub 3}]-[HX]. The ionic geometries, [NH{sub 4}{sup +}][X{sup -}], are not local minima on the potential energy surface and would not be stable after vaporization. For NH{sub 4}NO{sub 2}, [NH{sub 3}]-[trans-HONO] is the most stable isomer, and [NH{sub 3}]-[cis-HONO] and [NH{sub 3}]-[HNO{sub 2}] structures lie higher by 1.4 and 8.4 kcal/mol at the G1 level of theory. For the gaseous ADN, [NH{sub 3}]-HN(NO{sub 2}){sub 2} is the most stable structure, while the [NH{sub 3}]-[ON(O)NNO{sub 2}] isomer is 2.3 kcal/mol less favorable. The calculated dissociation energies of the [NH{sub 3}]-[HX] complex to NH{sub 3} and HX are 8-9 and 12-14 kcal/mol for NH{sub 4}NO{sub 2} and ADN, respectively. The energies for elimination of the NO{sub 2} group from HN(NO{sub 2}){sub 2} and HON(O)NNO{sub 2} are found to be 38-40 kcal/mol, while the barrier for HON(O)NNO{sub 2} dissociation is about 42 kcal/mol. 27 refs., 5 figs., 5 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 50484
• Journal Information: Journal of Physical Chemistry, Vol. 99, Issue 18; Other Information: PBD: 4 May 1995
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
99 MATHEMATICS
COMPUTERS
INFORMATION SCIENCE
MANAGEMENT
LAW
MISCELLANEOUS
AMMONIUM COMPOUNDS
THERMODYNAMIC PROPERTIES
DECOMPOSITION
MOLECULAR STRUCTURE
DISSOCIATION ENERGY
FORMATION HEAT
AMIDES
COMPILED DATA
NUMERICAL DATA
NITRITES
COMPLEXES
MOLECULAR ORBITAL METHOD
CALCULATION METHODS
ISOMERS