Effect of hydroxyl and nitrate ions on the sorption of ammonium ions by sulphonic cation exchangers

The sorption of ammonium ions and ammonia by the H+ form of sulphonic acid cation exchangers Amberlite 252, Lewatit 2629 and Relite C 360 from a solution containing NH₄NO₃ in the range of 0 to 0.214 equ/L and NH₃ in the range of 0.353 to 0 equ/L was investigated to establish the possibility of their application for the recovery of ammonium from caustic condensate generated in nitrogen fertilizer production. Breakthrough and elution curves were obtained, determining the concentration of ammonium with Nessler's reagent. The sorption of ammonium and ammonia depends on the concentration ratio of ammonia to ammonium nitrate [NH₃]/[NH₄NO₃]. On decreasing [NH₃]/[NH₄NO₃], the concentration ratio of hydroxyl to nitrate ions [OH⁻]/[NO⁻₃] and the effluent pH prior to NH⁺₄ breakthrough also decrease. This results in a decrease in the NH⁺₄ sorption because of a deficiency in the neutralization of hydrogen ions released (ordinary cation-exchange process). Thus, adverse circumstances create an unfavorable medium for NH⁺₄ removal from the caustic condensate. Maximum sorption of NH⁺₄ is attained at [NH₃]/[NH₄NO₃] ∼1.2. A further decrease in [NH₃]/[NH₄NO₃] is followed by a significant decrease in the effluent pH, which leads to an increase in the concentration of protonated sulphonic acid groups (-SO₃H), resulting in a decrease in the ion-exchange ability of the cation exchangers under investigation with respect to NH⁺₄ removal. The concentration (g/L) of NH₄NO₃ in the eluate from the cation-exchanger regeneration, carried out using 0.7 bed volumes (BV) of 20% HNO₃, amounts to 136.7 for Relite C 360, 119.5 for Lewatit K 2629 and 96.7 for Amberlite 252. The content of undamaged beads after 100 cycles (each cycle comprises saturation with caustic condensate, containing ammonia and ammonium, successive regeneration with 20% nitric acid and washing) is from 97 to 99.8%. Resistance to boiling in 20% HNO₃ solution is from 97 to 99.8%. These are applicable for the recovery of NH₄NO₃ from the caustic condensate in the nitrogen fertilizers production, preventing economic damage and environmental contamination from nitrogen compounds.     

ION EXCHANGE PROPERTIES OF BiO(NO3) 0.5H2O TOWARDS FLUORIDE IONS

ABSTRACT

We studied the ion exchange behavior of the inorganic anion exchanger BiO(NO₃)0.5H₂O with regard to fluoride ions. The ion exchange reaction was rapid at pH 1, 6.6, and 12. The mechanisms of ion exchange reactions at pH 1 and pH 2-12 were studied in a solution with fluoride ions excess to BiO(NO₃)0.5H₂O. A mixture of the β-phase and an unknown phase was produced in the solution at pH 1. BiOF was produced at pH 2-12. Fluoride ions did not react at pH 13, due to the decomposition of BiO(NO₃) 0.5H₂O at pH 13 to yield Bi₂O₃ (major) and Bi₂O₂CO₃ (minor). The structure of the reaction products depended on the solution pH, mole ratios of BiO(NO₃)0.5H₂O to F’, and the reaction time. We observed that BiO(NO₃)0.5H₂O is capable of removing 99% of the fluoride ions from the solution at pH 1-12 under optimal conditions. The ion exchange reaction of BiO(NO₃)0.5H₂O with fluoride ions was studied under the co-existence of both Cl and Br^?at pH 1, 6.6, 12, and 13. The order of decreasing affinity was found to be (Br^?, Cl^?)> F^?. The reaction product was not a simple mixture of BiOCl, BiOBr, and bismuth oxide fluorides, but an unknown compound.     

Solubilities in the ammonium thiosulfate-urea-ammonium nitrate-water system at 0°C

Solubilities in the system CO(NH₂)₂-NH₄NO₃-(NH₄)₂S₂O₃-H₂O were obtained at 0°C and pH values between 6.12 and 7.33. The new composition of matter, (NH₄)₆(S₂O₃)₂(NO₃)₂·CO(NH₂)₂, was identified and characterized chemically and microscopically. Stable high-analyses solution fertilizers can be produced at 0°C utilizing waste ammonium thiosulfate solutions with standard ammonium nitrate and urea fertilizer materials. A 31-0-0-5.6S grade (%N-%P₂O₅-%K₂O-Other) fertilizer solution can be formed at 0°C when NH₄NO₃/CO(NH₂)₂ is about one. Stable 30% total nitrogen solutions containing up to 10% sulfur can be produced at other NH₄NO₃/CO(NH₂)₂ ratios.     

A New Method for Nitration of Phenolic Compounds

Phenolic compounds can be nitrated by 65% nitric acid in the presence of catalytic amounts of montmorillonite KSF and bismuth(III) nitrate to give the corresponding nitrated products in good yields in a heterogeneous phase. The co‐catalyst of KSF and Bi(NO₃)₃ can be easily recovered and reused in the next batch of nitration.     

Indium-activated bismuth-based catalysts for efficient electrocatalytic synthesis of urea

Urea is of great importance for the survival and development of mankind because of its advantages in effectively increasing crop yields. A novel carbon-supported indium-doped bismuth nanoparticles (Bi: 10 %In/C NPs) was prepared for the synthesis of urea via the co-activated reduction of nitrate and CO₂ with an average Faraday efficiency (FE) of 20.31 % and urea yield (R_urea) of 606.38 μg mg⁻¹ h⁻¹. Interestingly, the In doped here not only serves as the active site, but also acts as an activator to stimulate the activity of Bi through electronic interaction, thus making Bi also the active site for the electrocatalytic C-N coupling reaction. Simultaneously, the key intermediates of the reaction are revealed to be *NH₂ and *CO. This work provides further insight into the role of indium in the electrocatalytic C-N coupling for the synthesis of urea, which gives a direction for thinking about the design and construction of subsequent highly efficient electrocatalysts.     

Nitrogen fertigation of greenhouse-grown strawberries

Two greenhouse experiments were conducted with strawberries (Fragaria ananassa) grown in plastic pots filled with 12 kg of soil, and irrigated by drip to evaluate the effect of 3 N levels and 3 N sources. The N levels were 3.6, 7.2 or 10.8 mmol Nl^–1 and the N sources were urea, ammonium nitrate and potassium nitrate for supplying NH₄/NO₃ in mmol Nl^–1 ratios of 7/0, 3.5/3.5 or 0/7, respectively. Both experiments were uniformly supplied with micronutrients and 1.7 and 5.0 mmoll^–1 of P and K, respectively. The fertilizers were supplied through the irrigation stream with every irrigation. The highest yield was obtained with the 7.2 mmol Nl^–1 due to increase in both weight and number of fruits per plant. With this N concentration soil ECe and NO₃-N concentration were kept at low levels. Total N and NO₃-N in laminae and petioles increased with increasing N level. With the N sources the highest yield was obtained with urea due to better fruit setting. The N source had no effect on soil salinity and residual soil NO₃-N; residual NH₄-N in the soils receiving urea and ammonium nitrate were at low levels.     

Effect of propylene carbonate on the ionic conductivity of polyacrylonitrile‐based solid polymer electrolytes

Solid polymer electrolyte membranes consisting of polyacrylonitrile (PAN) as a host polymer, ammonium nitrate (NH₄NO₃) as a complexing salt, and propylene carbonate (PC) as a plasticizer were prepared by a solution casting technique. An increase in the amorphous nature of the polymer electrolytes was confirmed by X‐ray diffraction analysis. A shift in the glass‐transition temperature of the PAN/NH₄NO₃/PC electrolytes was observed in the differential scanning calorimetry thermograms; this indicated interactions between the polymer and the salt. The impedance spectroscopy technique was used to study the mode of ion conduction in the plasticized polymer electrolyte. The highest ionic conductivity was found to be 7.48 × 10^?3 S/cm at 303 K for 80 mol % PAN, 20 mol % NH₄NO₃, and 0.02 mol % PC. The activation energy of the plasticized polymer electrolyte (80 mol % PAN/20 mol % NH₄NO₃/0.02 mol % PC) was found to be 0.08 eV; this was considerably lower than that of the film without the plasticizers. The dielectric behavior of the electrolyte is discussed in this article. A literature survey indicated that the synthesis and characterization of ammonium‐salt‐doped, proton‐conducting polymer electrolytes based on PAN has been rare. The use of the best composition membrane (80 mol % PAN/20 mol % NH₄NO₃/0.02 mol % PC) proton battery was constructed and evaluated. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41743.     

Reactivity at the film/solution interface of ex situ prepared bismuth film electrodes: A scanning electrochemical microscopy (SECM) and atomic force microscopy (AFM) investigation

Bismuth film electrodes (BiFEs) prepared ex situ with and without complexing bromide ions in the modification solution were investigated using scanning electrochemical microscopy (SECM) and atomic force microscopy (AFM). A feedback mode of the SECM was employed to examine the conductivity and reactivity of a series of thin bismuth films deposited onto disk glassy carbon substrate electrodes (GCEs) of 3 mm in diameter. A platinum micro-electrode (? = 25 μm) was used as the SECM tip, and current against tip/substrate distance was recorded in solutions containing either Ru(NH₃)₆³⁺ or Fe(CN)₆⁴⁻ species as redox mediators. With both redox mediators positive feedback approach curves were recorded, which indicated that the bismuth film deposition protocol associated with the addition of bromide ions in the modification solution did not compromise the conductivity of the bismuth film in comparison with that prepared without bromide. However, at the former Bi film a slight kinetic hindering was observed in recycling Ru(NH₃)₆³⁺, suggesting a different surface potential. On the other hand, the approach curves recorded by using Fe(CN)₆⁴⁻ showed that both types of the aforementioned bismuth films exhibited local reactivity with the oxidised form of the redox mediator, and that bismuth film obtained with bromide ions exhibited slightly lower reactivity. The use of SECM in the scanning operation mode allowed us to ascertain that the bismuth deposits were uniformly distributed across the whole surface of the glassy carbon substrate electrode. Comparative AFM measurements corroborated the above findings and additionally revealed a denser growth of smaller bismuth crystals over the surface of the substrate electrode in the presence of bromide ions, while the crystals were bigger but sparser in the absence of bromide ions in the modification solution.     

Kinetics and mechanism of the reaction between ammonium and nitrite ions: experimental and theoretical studies

The kinetics of the reaction between ammonium ion (NH₄⁺) and nitrite ion (NO₂⁻) in aqueous solutions was studied as a function of pH, temperature, and activities of the reactants. This reaction belongs to a class of fused chemical reactions that can be used to remediate paraffin and asphaltene deposition problems in oil pipelines. The reaction rate was found to be first-order with respect to the total concentration of ammonium species and second-order with respect to the total concentration of nitrite species. The reaction is strongly dependent on the pH of the solution, increasing the rate by a factor of 4000 as pH decreased from 7 to 3. The activity of hydrogen ion catalyzes the reaction by changing the concentrations of the two true reactants (ammonia (NH₃) and nitrogen trioxide (N₂O₃)), not by changing the reaction pathway. Reaction mechanisms were developed. A mechanism involving the S_N2 reaction in which the nucleophile NH₃ reacts with the electrophile N₂O₃ in the rate-limiting step was found to fit all experimental observations. This reaction mechanism releases the nitrite ion (NO₂⁻) to produce an intermediate (nitrosamine (H₂NNO)) which dissociates very rapidly to form the final products (nitrogen (N₂) and water (H₂O)).     

A hexanuclear cerium(IV) cluster with mixed coordination environment

Synthesis and structure of a modified intermediate derived from ammonium cerium(IV) nitrate for oxidative reactions as a hexanuclear cerium(IV) complex that has cerium ions in two different coordination environment is reported. The complex having ability to oxidise three moles of catechol to corresponding quinone has a composition NH₄[Ce₆(µ³-O)₅(µ³-OH)₃(µ²-C₆H₅COO)₉(NO₃)₃(DMF)₃].DMF.H₂O is prepared under room temperature and is characterised by X-ray crystallography.     

A microplot study of the fate of15N-labelled ammonium nitrate and urea applied at two rates to ryegrass in spring

Confined microplots were used to study the fate of¹⁵N-labelled ammonium nitrate and urea when applied to ryegrass in spring at 3 lowland sites (S1, S2 and S3). Urea and differentially and doubly labelled ammonium nitrate were applied at 50 and 100 kg N ha^–1. The % utilization of the¹⁵N-labelled fertilizer was measured in 3 cuts of herbage and in soil to a depth of 15 cm (soil_0–15).Over all rates, forms and sites, the % utilization values for cuts 1, 2, 3 and soil_0–15 were 52.4, 5.3, 2.4 and 16.0% respectively. The % utilization of¹⁵N in herbage varied little as the rate of application increased but the % utilization in the soil_0–15 decreased as the rate of application increased. The total % utilization values in herbage plus soil_0–15 indicated that losses of N increased from 12 to 25 kg N ha^–1 as the rate of N application was increased from 50 to 100 kg N ha^–1.The total % utilization values in herbage plus soil_0–15 over both rates of fertilizer N application were 84.1, 80.8 and 81.0% for urea compared with 74.9, 72.5 and 74.4% for all ammonium nitrate forms at S1, S2 and S3 respectively. Within ammonium nitrate forms, the total % utilization values in herbage plus soil_0–15 over both rates and all sites were 76.7, 69.4 and 75.7% for¹⁵NH₄NO₃, NH₄ ¹⁵NO₃ and¹⁵NH₄ ¹⁵NO₃ respectively. The utilization of the nitrate moiety of ammonium nitrate was lower than the utilization of the ammonium moiety.The distribution of labelled fertilizer between herbage and soil_0–15 varied with soil type. As the total utilization of labelled fertilizer was similar at all sites the cumulative losses due to denitrification and downward movement appeared to account for approximately equal amounts of N at each site.     

Modeling the Reactions Between Ammonia and Dinitrogen Pentoxide to Synthesize Ammonium Dinitramide (ADN)

Only three references about the reactions of ammonia (NH₃) with dinitrogen pentoxide (N₂O₅) have been published in the course of the last 150 years. None of them describes the reactions referring to the products in dependence on the reaction conditions. In this report the experimental results due to the reaction of NH₃ and N₂O₅ lead to three equations. One of these, the formation of dinitrogen oxide (N₂O) in addition to ammonium nitrate (NH₄NO₃; AN) was not mentioned before in the references available. The other reactions are known as the formation of ammonium dinitramide (NH₄N(NO₂)₂; ADN) and AN beside the formation and decomposition of nitramide (NH₂NO₂; NA) into water and dinitrogen oxide. Summarizing the known reactions of NH₃ with N₂O₅ and those of the intermediate products in a reaction scheme a model was established for the selectivity of ammonium dinitramide (ADN) and for the dependence on the reaction conditions. The model is in good accordance with the experimental results.     

New approaches to prepare nitrogen-doped TiO2 photocatalysts and study on their photocatalytic activities in visible light

Nitrogen-doped TiO₂ nanocatalysts were successfully synthesized by adjusting a pH range using the ammonium nitrate and ammonia water as the nitrogen source. The samples were characterized by XRD, XPS and UV-DRS. When the total amount of ammonium nitrate and ammonia water was unchanged, different pH values were modified by changing the NH₄NO₃/NH₃·H₂O ratio to prepare nitrogen-doped TiO₂. The prepared photocatalyst showed the highest photo-activity for the degradation of 2,4-dichlorophenol (2,4-DCP) under visible light when prepared at pH 5.87. XPS analysis showed the presence of nitrogen in two states doped in TiO₂. The results indicated the photocatalytic activity of N-TiO₂ is varied with the change of pH values, the amount of the nitrogen sources and water. The experimental results showed that the higher activity is due to the variation in the concentration and states of nitrogen-doped in TiO₂. In the preparation methods, the photocatalyst was treated with the hydrogen peroxide before calcination, resulting in the decrease of nitrogen doped into the lattice and the photo-degradation rate of 2,4-DCP. The results suggested that the nitrogen source could be doped into the crystal lattice only in the form of reduction state as NH₄⁺ ion during the calcination process.     

Effects of mineral nitrogen andBradyrhizobium inoculation on growth and iron nutrition of groundnut

Experiments were conducted in a glasshouse to determine the effects of the mineral N supplied as ammonium nitrate andBradyrhizobium inoculation on the growth and iron nutrition of nodulating and non-nodulating groundnut (Arachis hypogaea L.) lines. In a sterilized sand-vermiculite medium supplied with N-free nutrient solution (pH 7.0), inoculation of nodulating groundnut withBradyrhizobium strain NC 43.3 enhanced dry matter production and O-phenanthroline extractable iron and N contents of the plants. The supply of mineral N at a rate of 100 mg N L^–1 (as NH₄NO₃) through deionized water (pH 8.5) induced iron chlorosis symptoms in the nodulating groundnuts grown in Vertisols, but these symptoms were not observed at higher N levels (200–400 mg N L^–1). The induced chlorosis was only partially corrected by inoculation withBradyrhizobium strains NC 92 and NC 43.3. The iron deficiency chlorosis was, however, corrected by application of higher rates of ammonium nitrate.Submitted as JA No. 942 of the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)     

Analysis of ADN,Its Precursor and Possible By‐Products Using Ion Chromatography

In the last years ammonium dinitramide (ADN) appeared to be a promising new oxidator and a possible substitute for ammonium nitrate (AN) and especially for the chlorinated oxidizer ammonium perchlorate. Among other main advantages of ADN are to be mentioned the higher energy input combined with a reduced pressure in application. Furthermore, ADN shows no phase transitions like AN. For evaluating the purity of the synthesized and/or treated or aged pure or formulated ADN, the estimated ammonium nitrate content was taken into account. AN is known to be as well a by‐product of the ADN synthesis as a possible decomposition product of ADN. Thermally treated ADN decomposes mainly to N₂O, H₂O, NO₂ and AN which further reacts to N₂O and NH₃. Determining the nitrate contents assuming the rest being intact ADN must not lead to correct values especially in cases where ADN was treated/handled at higher temperatures in open systems. Concerning the technical scale synthesis of ADN, the precursor ammonium nitrourethane (ANU) must be eliminated in a quick but sufficient way needing a suitable analysis method for detecting nitrourethane besides nitrate and ADN. The objective of this work was to develop a suitable ion chromatographic method for the direct analysis of the anions concerned. Different ion exchanger phases were tested with organic and/or inorganic eluants. The ionic strength and flow rate of the eluant was improved to get an acceptable resolution for nitrite and nitrate combined with a short run time for the whole analysis. Detection was realized by electrical conductivity or UV absorption whereby the measurement wavelengths were optimized in order to get a small signal‐to‐noise ratio and simultaneously a suitable sensitivity especially for NO₃⁻ and nitrourethane. Under improved conditions (Ion Pac 11, 1 ml/min NaOH, 300 mmol), limits of detection (LOD) of 0.05 to 0.01 ppm were realized for NO₃⁻ and NO₂⁻, respectively, measured at 214 nm. Using 220 nm as detection wavelength resulted in a LOD of about 0.3 ppm for nitrate. Using a wavelength between 210 and 220 nm results in a LOD for ANU of about 1 ppm. The linearity range for the analysis of DN⁻ (285 nm) was found to be very broad (up to 700 ppm). All anions can be analyzed in one run taking maximally 30 minutes.     

Displacement of Ammonium from Aerosol Particles by Uptake of Triethylamine

The displacement of ammonium by triethylammonium (TEAH) in aerosol particles of about 15–35 μm in diameter was investigated using an electrodynamic balance (EDB) coupled with in situ Raman spectroscopy. The phase state of particles played a crucial role in the extent of triethylamine (TEA) uptake. At 50 or 75% relative humidity (RH), the heterogenous uptake of about 40-ppm TEA by aqueous ammonium salts of sulfate [(NH₄)₂SO₄], bisulfate (NH₄HSO₄), nitrate (NH₄NO₃), chloride (NH₄Cl), and oxalate [(NH₄)₂C₂O₄] led to increases in particle mass of over 90%. A complete displacement of ammonium by TEAH was confirmed by direct EDB mass measurements and the Raman spectra obtained. TEAH sulfate was formed during the exposure of aqueous droplets of (NH₄)₂SO₄ and NH₄HSO₄ to TEA vapor at 50% RH; but a fraction of it decomposed to TEAH bisulfate when the TEA supply was removed. Crystalline solid particles of (NH₄)₂SO₄ and (NH₄)₂C₂O₄ experienced small mass increases of <5%, both of which were attributed to the hindered mass transfer of TEA in crystalline solids. However, TEA reacted with the amorphous solid NH₄NO₃ particle at <3% RH as effectively as if it was in the aqueous NH₄NO₃ droplet (50% RH) and formed TEAH nitrate. On the other hand, the amorphous NH₄HSO₄ solid particle reacted with TEA at <3% RH to form crystalline (NH₄)₂SO₄ and liquid TEAH bisulfate and sulfate. The formation of rather inert crystalline (NH₄)₂SO₄ suppressed the ammonium exchange.

Copyright 2012 American Association for Aerosol Research     

Hydrolysis to the first dumbbell-like high-nuclearity bismuth-oxo cluster [Bi12(μ3-OH)4(μ2-OH)2(μ3-O)8(μ4-O)2(NO3)6]4+: Synthesis,structure and spectroscopic characterizations

The first dumbbell-like high-nuclearity bismuth-oxo cluster [Bi₁₂(μ₃-OH)₄(μ₂-OH)₂(μ₃-O)₈(μ₄-O)₂(NO₃)₆](NO₃)₄ · 6H₂O was obtained by diffusing ethanol into the hydrolysate of Bi(NO₃)₃ aqueous solution. The dumbbell consists of two Bi–O bonds as the handle and two [Bi₆(μ₃-OH)₂(μ₂-OH)(μ₃-O)₄(μ₄-O)] subunits as the bells. The bell can be regarded as a piercing bracelet-like ring consisted of six edge-sharing tetragons with one cross section enveloped by one μ₃-O linking three Bi(III) atoms and the other connected by one μ₂-O as a open cover. The structure is further stabilized by the interactions of Bi⋯Bi, Bi⋯O and hydrogen bondings. The optical gap of 2.85 eV suggests that the title compound behaves as semiconductors. The title compound features a blue fluorescence at 441 nm, which is assigned to ¹P₁–¹S₀ and ³P–¹S₀ transitions from the s² electron of Bi³⁺ cation.     

Effects of soil fumigation and N source on soil inorganic N and tomato growth

Soil fumigation, commonly used in vegetable production, may alter the rate of nitrification, affecting availability of N for crop use. The objective of this research was to examine effects of soil fumigation and N fertilizer source on tomato growth and soil NO₃–N and NH₄–N in field production. Experiments 1 and 2 included application of methyl bromide at 420 kg ha^-1 to a Norfolk sandy loam (fine loamy siliceous thermic Typic Kandiudult) in combination with preplant applications of calcium nitrate, ammonium nitrate, and ammonium sulfate at 144 kg N ha^-1. An additional fumigant, metam-sodium, was included in the second experiment at 703 L ha^-1 (268 kg sodium methyldithiocarbamate ha^-1). Experiment 3 included methyl bromide and metam-sodium, with ammonium sulfate as the sole source of N applied at 144 kg N ha^-1. In the first two studies, fumigants had little or no effect on soil NH₄–N or NO₃–N concentration. Tomato plants were larger and fruit yield was greater in fumigated plots, but there were few growth or yield responses to N source. In the third experiment, fumigants increased concentration of soil NO₃–N and NH₄–N at 16 days after fumigation (DAF), however, there was no effect on nitrification owing to fumigants. It appears that N source selection to overcome inhibition of nitrification is not necessary in plant production systems that involve fumigation     

Thermal Decomposition of Energetic Materials 41. Fast thermolysis of cyclic and acyclic ethanediammonium dinitrate salts and their oxonium nitrate double salts,and the crystal structure of piperazinium dinitrate

Fast thermolysis/FTIR spectroscopy of [H₃NCH₂CH₂NH₃]-(NO₃)₂ (EDD), [H₂N(CH₂CH₂)₂NH₂](NO₃)₂ (PIPDN), and [HN(CH₂CH₂)₃NH](NO₃)₂(DABCOD) and new oxonium nitrate (H₃O⁺NO⁻³) double salts of PIPDN and DABCOD is described. EDD initially yields HNO₃ and then small molecule decomposition products from redox reactions when heated at ≥ 100°C (dcc.). PIPDN initially yields HNO₃, but then generates a significant amount of N,N′-dinitrosopiperazine along with small molecule fragments. DABCOD produces no HNO₃(g), but instead gives CH₂O, N,N′-dinitrosopiperazine and small molecule products. These patterns are entirely consistent with the behavior observed for primary, secondary and teritary ammonium mononitrate salts in our previous work. The presence of nitrosamines strongly increases the health hazard of the matcrials upon heating. No nitramines were detected as thermolysis products. Thermolysis of the oxonium nitrate double salts liberates HNO₃ and H₂O at a relatively low temperature (≥ 60 °C). Above this temperature, the thenmolysis proceeds in the same way as that of pure PIPDN and DABCOD. The crystal structure of PIPDN is described.