Nitrogen oxide (N2O5) (10102-03-1) Physical and Chemical Properties
Nitrogen oxide (N2O5)
An inorganic nitrogen oxide used as a potent nitrating and oxidizing reagent in specialty chemical synthesis; procurement and handling require moisture‑free storage and process controls.
| CAS Number | 10102-03-1 |
| Family | Nitrogen oxides |
| Typical Form | Colorless crystalline solid |
| Common Grades | EP |
Dinitrogen pentoxide is an inorganic nitrogen oxide belonging to the class of nitrogen oxyanions/anhydrides and is commonly described as the anhydride of nitric acid. Structurally it can be represented by the molecular formula \(\ce{N2O5}\); bonding descriptions vary with phase and environment, ranging from a covalent \(\ce{O2N–O–NO2}\) connectivity to an ion-pair description composed of nitronium and nitrate units. The molecule is highly oxidized (formal oxidation state of nitrogen averaging +5) and presents a high oxygen content per nitrogen, which gives it strong electrophilic and oxidizing character in chemical reactions.
Electronically the species exhibits polarized N–O bonds and a high topological polar surface area (TPSA = 101), consistent with a low hydrogen-bond donor count (0) and multiple oxygen lone-pair acceptor sites. It is essentially non‑basic and functions as an acid anhydride: hydrolysis produces strong acid(s), and in nonaqueous media it can generate the nitronium electrophile. Physicochemical behavior is dominated by hydrolysis susceptibility, oxidative reactivity with organic substrates, and thermal lability near its solid–liquid transition.
Common commercial grades reported for this substance include: EP.
Basic Physical Properties
Density
No experimentally established value for this property is available in the current data context.
Melting or Decomposition Point
Experimental description reports a colorless solid with melting point \(30\,^\circ\mathrm{C}\). The material is thermally labile around the solid–liquid transition and should be treated with care near and above this temperature due to increased reactivity and tendency to hydrolyze or decompose.
Solubility in Water
Dinitrogen pentoxide does not behave as a simple, inert solute in water; it hydrolyzes to give nitric acid. Contact with water therefore results in chemical conversion rather than simple dissolution, with evolution of heat in concentrated systems and rapid formation of acidic solutions containing \(\ce{HNO3}\). In practice aqueous handling should be avoided; when contacting moisture the resulting solution is strongly acidic and corrosive.
Solution pH (Qualitative Behavior)
Solutions produced by hydrolysis are strongly acidic because \(\ce{N2O5}\) is the anhydride of nitric acid. No experimentally established numeric pH value is available in the current data context, but expect low \(\mathrm{pH}\) (acidic) for hydrolysis products.
Chemical Properties
Acid–Base Behavior
\(\ce{N2O5}\) functions as the anhydride of nitric acid (\(\ce{HNO3}\)). Reaction with water yields nitric acid; conceptually: \[ \ce{N2O5 + H2O -> 2 HNO3} \] In nonaqueous or strongly dehydrating media, \(\ce{N2O5}\) can act as a nitrating reagent by generating the nitronium electrophile \(\ce{NO2+}\), enabling electrophilic nitration of activated and some deactivated aromatic substrates.
Reactivity and Stability
The compound is a strong oxidizing/nitrating agent and is chemically reactive toward organic substrates, reducing agents, and moisture. It is thermally and hydrolytically unstable relative to lower oxides of nitrogen and to nitric acid; elevated temperature and exposure to water substantially increase its reactivity. Solutions in nonaqueous solvents (e.g., chlorinated solvents) are used to moderate reactivity for nitration applications, but handling requires strict control of moisture and organic contaminants to avoid uncontrolled reactions. No detailed quantitative decomposition kinetics are provided in the current data context.
Molecular and Ionic Parameters
Formula and Molecular Weight
- Molecular formula: \(\ce{N2O5}\)
- Molecular weight: 108.01 \(\mathrm{g}\,\mathrm{mol}^{-1}\)
- Exact/monoisotopic mass: 107.98072110
Additional computed descriptors: XLogP3 = 0.7; topological polar surface area (TPSA) = 101; hydrogen bond donor count = 0; hydrogen bond acceptor count = 5; rotatable bond count = 0.
Constituent Ions
Solid‑state and resonance descriptions permit an ionic interpretation in which nitronium and nitrate moieties are present (formally \(\ce{NO2+}\) and \(\ce{NO3-}\)). In solution and under reaction conditions the active electrophile for nitration is commonly described as \(\ce{NO2+}\). The neutral, covalently connected representation \(\ce{O2N–O–NO2}\) is also used to describe the molecular connectivity in some phases.
Identifiers and Synonyms
Registry Numbers and Codes
- CAS number: 10102-03-1
- EC number: 233-264-2
- UNII: 6XB659ZX2W
- ChEBI ID: CHEBI:29802
- DSSTox Substance ID: DTXSID90143672
- InChI:
InChI=1S/N2O5/c3-1(4)7-2(5)6 - InChIKey:
ZWWCURLKEXEFQT-UHFFFAOYSA-N - SMILES:
[N+](=O)([O-])O[N+](=O)[O-]
Synonyms and Common Names
- Dinitrogen pentaoxide
- Dinitrogen pentoxide
- Nitrogen pentoxide
- Nitric anhydride
- Nitro nitrate
- Nitrogen oxide (N2O5)
- Distickstoffpentoxid (German)
- Salpetersaeureanhydrid (German)
(Several additional depositor-supplied synonyms and registry cross‑references exist; the list above includes principal names and descriptive synonyms.)
Industrial and Commercial Applications
Functional Roles and Use Sectors
Dinitrogen pentoxide is used as an oxidizing nitrating reagent in organic synthesis. Its principal technical role is to provide an electrophilic nitration capability in nonaqueous media where generation and control of the nitronium species are required. Because of its strong oxidizing and hydrolysis-prone nature, use is predominantly restricted to controlled laboratory and industrial processes with appropriate dry, inert conditions.
Typical Application Examples
A documented application is use in chloroform solution as a nitrating agent for aromatic substrates. Typical application contexts are nitration steps in specialty chemical synthesis and research‑scale electrophilic nitrations where other nitrating systems are unsuitable or where a reagent that directly generates \(\ce{NO2+}\) under anhydrous conditions is desired.
Safety and Handling Overview
Health and Environmental Hazards
Nitrogen oxides, including dinitrogen pentoxide, are respiratory irritants and may be toxic by inhalation. Reported acute effects associated with related nitrogen oxides include upper respiratory irritation, cough, conjunctivitis, dyspnea, headache, and the potential for delayed pulmonary edema. Survivors of severe pulmonary edema may develop chronic airway complications. On contact with moisture (including body moisture) dinitrogen pentoxide forms nitric acid, which is corrosive. Toxicological information specific to \(\ce{N2O5}\) is limited, but reported adverse effects associated with exposure to nitrogen oxides include methemoglobinemia, toxic pneumonitis, chronic bronchitis and fibrogenic lung injury.
Storage and Handling Considerations
Handle under strictly anhydrous conditions in a well‑ventilated fume hood or appropriate containment. Store in a cool, dry, tightly closed container, away from water, strong reducing agents, organic materials, and bases. Segregate from combustible materials and incompatible substances. Use appropriate personal protective equipment (chemical‑resistant gloves, eye/face protection, and respiratory protection where inhalation exposure cannot be controlled). In case of exposure or spillage, avoid contact with water on a large scale that could generate corrosive acidic solutions; neutralization and cleanup should be performed by trained personnel using procedures appropriate for oxidizing acids. For detailed hazard, transport and regulatory information, users should refer to the product‑specific Safety Data Sheet (SDS) and local legislation.
