Search

Nucleation of neutral iodine particles has recently been found to involve both iodic acid (HIO3) and iodous acid (HIO2). However, the precise role of HIO2in iodine oxoacid nucleation remains unclear. Herein, we probe such a role by investigating the cluster formation mechanisms and kinetics of (HIO3)m(HIO2)n(m = 0-4, n = 0-4) clusters with quantum chemical calculations and atmospheric cluster dynamics modeling. When compared with HIO3, we find that HIO2binds more strongly with HIO3and also more strongly with HIO2. After accounting for ambient vapor concentrations, the fastest nucleation rate is predicted for mixed HIO3-HIO2clusters rather than for pure HIO3or HIO2ones. Our calculations reveal that the strong binding results from HIO2exhibiting a base behavior (accepting a proton from HIO3) and forming stronger halogen bonds. Moreover, the binding energies of (HIO3)m(HIO2)nclusters show a far more tolerant choice of growth paths when compared with the strict stoichiometry required for sulfuric acid-base nucleation. Our predicted cluster formation rates and dimer concentrations are acceptably consistent with those measured by the Cosmic Leaving Outdoor Droplets (CLOUD) experiment. This study suggests that HIO2could facilitate the nucleation of other acids beyond HIO3in regions where base vapors such as ammonia or amines are scarce. publishedVersion

A detailed analysis of the acousto-optical effect in biaxial crystals is performed using the examples of thallium tetratioarsenate (Tl3AsS4) and iodic acid (α-HIO3) crystals of rhombic syngony. The optimum cross sections of the crystals are determined for such acousto-optical devices as deflectors and filters. The prospects for using thallium tetratioarsenate crystal to create high-performance acousto-optical deflectors and quasi-collinear filters in the near- and mid-IR ranges are demonstrated. It is established that the spectral resolution of acousto-optical filters based on this variant of diffraction is comparable to the resolution of quasi-collinear filters with the same length of acousto-optical interaction.

Gaseous sulfur compounds are emitted from many facilities, such as wastewater facilities or biomass power plants, due to the decay of organic compounds. Gaseous dimethyl sulfide removal by ozone catalytic oxidation was investigated in this study. A Vacuum-Ultra-Violet (VUV) xenon excimer lamp of 172 nm was used for ozone generation without NOx generation, and activated carbon impregnated with iodic acid and H2SO4 was utilized as a catalyst. Performance assessment of dimethyl sulfide removal ability was carried out by a dynamic adsorption experiment. Empty-Bed-Contact-Time (EBCT), superficial velocity, concentration of dimethyl sulfide, temperature and humidity were set at 0.48 s, 0.15 m/s, 3.0 ppm, 25 °C and 45%, respectively. Without ozone addition, the adsorption capacity of impregnated activated carbon was 0.01 kg/kg. When ozone of 7.5 ppm was added, the adsorption capacity of impregnated activated carbon was increased to 0.15 kg/kg. Methane sulfonic acid, a reaction product of dimethyl sulfide and ozone, was detected from the activated carbon. The results suggest that the VUV and activated carbon impregnated with iodic acid and H2SO4 are workable for ozone catalytic oxidation for gas treatments.

During summer, the Southern Ocean is largely unaffected by anthropogenic emissions, which makes this region an ideal place to investigate marine natural aerosol sources and processes. A better understanding of natural aerosol is key to constrain the preindustrial aerosol state and reduce the aerosol radiative forcing uncertainty in global climate models. We report the concentrations of gaseous sulfuric acid, iodic acid, and methanesulfonic acid (MSA) together with a characterization of new particle formation (NPF) events over a large stretch of the Southern Ocean. Measurements were conducted on board the Russian icebreaker Akademik Tryoshnikov from January to March 2017. Iodic acid is characterized by a particular diurnal cycle with reduced concentration around noon, suggesting a lower formation yield when solar irradiance is higher. Gaseous MSA does not have a diurnal cycle and measured concentrations in gas and condensed phase are compatible with this species being primarily produced via heterogeneous oxidation of dimethyl sulfide and subsequent partitioning into the gas phase. We also found that NPF in the boundary layer is mainly driven by sulfuric acid but it occurred very rarely over the vast geographical area probed and did not contribute to the cloud condensation nuclei budget in a directly observable manner. Despite the near absence of NPF events in the boundary layer, Aitken mode particles were frequently measured, supporting the hypothesis of a free tropospheric source. Iodic acid and MSA were not found to participate in nucleation, however, MSA may contribute to aerosol growth via heterogeneous formation in the aqueous phase.

Both iodic acid (HIO3, IA) and methanesulfonic acid (CH3S(O)2OH, MSA) have been identified by field studies as important precursors of new particle formation (NPF) in marine areas. However, the mechanism of NPF in which IA and MSA are jointly involved is still unclear. Hence, we investigated the IA-MSA nucleation system under different atmospheric conditions and uncovered the corresponding nucleating mechanism at a molecular level for the first time using quantum chemical approach and Atmospheric Cluster Dynamics Code (ACDC). The findings showed that MSA can stabilize IA clusters via both hydrogen and halogen bonds. Moreover, the joint nucleation rate of IA-MSA system is significantly higher than that of IA self-nucleation, particularly in relatively cold marine regions with sparse IA and rich MSA. For the IA-MSA nucleation mechanism, in addition to self-nucleation of IA, the IA-MSA-involved clusters can also directly participate in the nucleation process, and their contribution is particularly prominent in the polar regions with rich MSA and sparse IA. The IA-MSA nucleation mechanism revealed in this work may help to elucidate some missing sources of marine NPF.

Polymer films with regular pores oriented perpendicular to the surface are obtained by irradiating a polymer film with synchrotron radiation through a mask followed by the chemical etching of destruction zones. Optical and electron microscopic studies of regular and irregular porous structures are carried out. The observed diffraction at the regular porous polymer film suggests it is promising for use as a diffraction component. On the basis of a porous polymer film, dielectric microstructures of iodic acid (HIO3) are obtained using the template method.

This paper studies the propagation of symmetric and antisymmetric Lamb waves along a 1 mm thick iodic acid plate (HIO3) in the 1–50 MHz frequency range. The Lamb mode propagation along three crystallographic planes was theoretically investigated, for two mutually orthogonal propagation directions. Several frequencies were found that correspond to Lamb modes with zero group velocity (ZGV) and non-null phase velocity values. The first symmetric Lamb mode, S1, was found to possess only one ZGV point, regardless of the propagation direction; higher order symmetric and antisymmetric modes with up to four ZGV points were found, depending on the propagation plane. The dependence of the ZGV frequencies on each elastic constant (c11, c13, c33, c55) of the HIO3 plate material was also investigated by changing the constant values by 5% and 10%. It was found that c33 and c55 affect the number of the ZGV points, while c11 and c13 affect the frequency of the ZGV points. The existence and frequencies of the ZGV points are strongly dependent on the proximity of standing longitudinal and transverse waves at nearby cutoff frequencies.

The interaction of ethylenediamine with iodic acid by the slow evaporation method at room temperature gives rise to the crystals of α-C2H10N2(IO3)2 and β-C2H10N2(IO3)2 denoted as α-EBI and β-EBI, respectively. The acentric crystal structures of both polymorphs that consist of [C2H10N2]2+ cations and [IO3]− anions connected together by N–H…O hydrogen bonds are discussed and compared. The optical properties of both polymorphs were determined using UV-vis diffuse reflectance spectroscopy (DRS) showing a wide transparency windows. The DFT calculations using the mixed B3PW91/[6–31 + (d, p), LanL2Dz] basis set of optimized geometries, dipole moment (μ), polarizability (α), first static hyperpolarizability (β), and population analysis were also reported. The experimental and theoretical IR and Raman spectra were compared, and the careful and complete assignment of the vibrational motions of both compounds was undertaken with the aid of potential energy distribution (PED) analysis. DSC and AC conductivity analysis revealed that α-C2H10N2(IO3)2 and β-C2H10N2(IO3)2 undergo a first-order phase transition around 360 K. The electrical σtot (ω, T) conductivity obeyed to Jonscher’s power law and the temperature dependence of the S(T) parameter showed that the electrical conductivity of both polymorph phases might be treated using the correlated barrier hopping (CBH) model.

This work describes exploration of mitigating the parasitic amorphous alumina (Al2O3) shell of aluminum nanoparticles (n-Al) and modifying the surface using different plasmas, leading to n-Al with thinner shell and different coatings including carbons and oxidizing salt called aluminum iodate hexahydrate (AIH), respectively. The approach exploits a prototype atmospheric non-thermal plasma reactor with dielectric barrier discharge (DBD) configuration for nanoparticle surface modifications using n-Al of 80 nm average diameter as an example. Preliminary results indicate that the amorphous Al2O3 shell surrounding the active aluminum core can be mitigated with inert plasmas by as much as 40% using either helium (He) or argon (Ar). The particle surface becomes carbon-rich with carbon monoxide (CO) / He plasmas. By immersing the plasma-treated n-Al in an iodic acid (HIO3) solution, AIH crystals can be formed on the n-Al surface. Transmission electron microscopy (TEM) is used as a major tool to study the details of the modified surface morphologies, diffraction patterns, and chemical composition of the modified n-Al. The results demonstrate effective surface passivation of n-Al via atmospheric plasma techniques.

This work presents a facile approach for preparing porous graphitic carbon nitride tubes with cyano groups and carbon vacancies (I/N-CN) through thermal polymerization of the pre-assembled melamine–cyanuric acid supramolecules from melamine by a mixed iodic acid/nitric acid assisted hydrothermal process. I/N-CN demonstrates 3.64-fold higher visible-light-driven hydrogen evolution rate (9.75 μmol h−1) than the traditional tubular carbon nitride (HCN) prepared without iodic acid or nitric acid, originating from the promoted light absorption extending to the near-infrared region, accelerated electron transfer, inhibited recombination of charge carriers, higher reduction capability, more accessible active sites from the combination of porous tubular structure and enriched cyano groups and carbon vacancies.

Chemical Ionisation Mass Spectrometry (CIMS) using I− (the iodide anion) as primary chemi-ion has previously been used to measure NO3 and N2O5 both in laboratory and field experiments. We show that reports of the large daytime mixing ratios of NO3 and N2O5 (usually only present in detectable amounts at night-time) are likely to be heavily biased by the ubiquitous presence of HNO3 in the troposphere and lower stratosphere. We demonstrate in a series of laboratory experiments that the CIMS detection of HNO3 at m/z 62 using I− ions is efficient in the presence of PAN or peracetic acid (PAA) and especially O3. We have characterised the dependence of the sensitivity to HNO3 detection on the presence of acetate anions (CH3CO2−, m/z 59, from either PAN or PAA). The loss of CH3CO2− via conversion to NO3− in the presence of HNO3 may represent a significant bias in I-CIMS measurements of PAN and CH3C(O)OOH. The largest sensitivity to HNO3 at m/z 62 is achieved in the presence of ambient levels of O3 whereby the thermodynamically disfavoured, direct reaction of I− with HNO3 to form NO3− is bypassed by the formation of IOX− which react with HNO3 to form e.g. iodic acid and NO3−. The ozone and humidity dependence of the detection of HNO3 at m/z 62 was characterised in laboratory experiments and applied to daytime, airborne measurements in which very good agreement with measurements of the I−(HNO3) cluster-ion (specific for HNO3 detection) was obtained.

In this study, a low temperature hydro iodic acid (HI) vapor treatment of the self-assembled graphene films has been developed, and the electrical, optical, structural and morphological properties were investigated by four point probe, UV-Visible spectroscopy, Raman spectroscopy and scanning electron microscopy (SEM). Mono-, doubleand triple-layer of graphene flakes were deposited on glass substrates by using the Double Self-Assembly (DSA) process. The self-assembled graphene films were treated with HI vapors at 40 degrees C for different time intervals between 1 and 24 h. In addition, graphene deposition and HI-vapor treatment (at 40 degrees C for 1 h) was enforced three times to the same substrate. The optical transparency values of the self-assembled mono- (MGFs), double- (DGFs) and triple-layer graphene flakes (TGFs) were measured as 91, 85 and 80%, respectively (values at 550 nm). Due to the HI-vapor treatment, the sheet resistance of MGFs significantly reduced from 1.1 x 10(7) Omega omega square(-1) to 2.9 x 10(4) omega square(-1), the transparency of the graphene films slightly reduced by 2-5%, the I-D/I-G ratio of the DGFs decreased from 1.01 to 0.81, while the I-2D/I-G ratio increased from 0.43 to 0.48 in the Raman spectrum. Thanks to its impressive reducing effect on sheet resistance, HI-vapor treatment can be a suitable method to improve the conductivity of low-cost large area graphene films. Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK)

Diiodine trioxide (I2O3) is one of the most common iodine oxides in the marine boundary layer (MBL). Both theoretical and experimental studies have confirmed that they can be quickly formed and are relatively stable under dry conditions. However, there is no report on the field observation of I2O3, which means that I2O3 is likely to be lost in the actual marine atmosphere. But the specific loss pathways and mechanisms are still unclear. Considering that the humidity in the marine regions is generally high and the loss of I2O3 will be affected by some substances in the marine atmosphere, water (H2O, W) and iodic acid (HIO3, IA) were selected as a catalyst to investigate the catalytic hydration mechanisms of I2O3 at DLPNOCCSD(T)//ωB97X-D/aug-cc-pVTZ + aug-cc-pVTZ -PP (for iodine) level of theory. The results show that hydration of I2O3 presents a high energy barrier, but IA can reduce it to 3.76 kcal/mol. Therefore, in the marine atmosphere, I2O3 can be hydrolyzed under the catalysis of IA, and cannot directly participate in the new particle formation process.

Open Access Article. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/., Emitted from the oceans, iodine-bearing molecules are ubiquitous in the atmosphere and a source of new atmospheric aerosol particles of potentially global significance. However, its inclusion in atmospheric models is hindered by a lack of understanding of the first steps of the photochemical gas-to-particle conversion mechanism. Our laboratory results show that under a high humidity and low HOx regime, the recently proposed nucleating molecule (iodic acid, HOIO2) does not form rapidly enough, and gas-to-particle conversion proceeds by clustering of iodine oxides (IxOy), albeit at slower rates than under dryer conditions. Moreover, we show experimentally that gas-phase HOIO2 is not necessary for the formation of HOIO2-containing particles. These insights help to explain new particle formation in the relatively dry polar regions and, more generally, provide for the first time a thermochemically feasible molecular mechanism from ocean iodine emissions to atmospheric particles that is currently missing in model calculations of aerosol radiative forcing. © 2020, The Author(s)., This study has received funding from the European Research Council Executive Agency under the European Union’s Horizon 2020 Research and Innovation programme (Project “ERC-2016-COG 726349 CLIMAHAL”). J.C.G.M. acknowledges financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709), the Ramon y Cajal Program (RYC-2016-19570) and the National I + D + i Program (RTI2018-095330-B-100). We thank the Holland Computing Center of the University of Nebraska—Lincoln for providing computing resources.

Iodine is enriched in marine aerosols, particularly in coastal mid-latitude atmospheric environments, where it initiates the formation of new aerosol particles with iodic acid (HIO3) composition. However, particle formation in polluted and semipolluted locations is inhibited when the iodine monoxide radical (IO) is intercepted by NO2 to form the iodine nitrate (IONO2). The primary fate of IONO2 is believed to be, besides photolysis, uptake by aerosol surfaces, leading to particulate iodine activation. Herein we have performed Born-Oppenheimer molecular dynamics (BOMD) simulations and gas-phase quantum chemical calculations to study the iodine acids-iodine nitrate [HIOx (x = 2 and 3)-IONO2] dynamics at the air-water interface modeled by a water droplet of 191 water molecules. The results indicate that IONO2 does not react directly with these iodine acids, but forms an unusual kind of interaction with them within a few picoseconds, which is characterized as halogen bonding. The halogen bond-driven HIO3-IONO2 complex at the air-water interface undergoes deprotonation and exists as IO3--IONO2 anion, whereas the HIO2-IONO2 complex does not exhibit any proton loss to the interfacial water molecules. The gas-phase quantum chemical calculations suggest that the HIO3-IONO2 and HIO2-IONO2 complexes have appreciable stabilization energies, which are significantly enhanced upon deprotonation of iodine acids, indicating that these halogen bonds are fairly stable. These IONO2-induced halogen bonds explain the rapid loss of IONO2 to background aerosol. Moreover, they appear to work against iodide formation. Thus, they may play an important role in enhancing the amount of atmospherically nonrecyclable iodine (iodate) in marine aerosol. © 2020 American Chemical Society, This work was supported by the University of Nebraska Holland Computing Center.

Ions enhance the formation rate of atmospheric aerosol particles, which play an important role in Earth’s radiative balance. Ion-induced nucleation involves the stepwise accretion of neutral monomers onto a molecular cluster containing an ion, which helps to stabilize the cluster against evaporation. Although theoretical frameworks exist to calculate the collision rate coefficients between neutral molecules and ions, they need to be experimentally confirmed, ideally under atmospherically relevant conditions of around 1000 ion pairs cm−3. Here, in experiments performed under atmospheric conditions in the CERN CLOUD chamber, we have measured the collision rate coefficients between neutral iodic acid (HIO3) monomers and charged iodic acid molecular clusters containing up to 11 iodine atoms. Three methods were analytically derived to calculate ion-polar molecule collision rate coefficients. After evaluation with a kinetic model, the 50% appearance time method is found to be the most robust. The measured collision rate coefficient, averaged over all iodine clusters, is (2.4 ± 0.8)×10−9 cm3 s−1, which is close to the expectation from the surface charge capture theory.

Atmospheric measurement techniques 13(5), 2501 - 2522 (2020). doi:10.5194/amt-13-2501-2020, Published by Copernicus, Katlenburg-Lindau

11 pags., 4 figs.-- Correction: https://www.nature.com/articles/s41467-020-19533-y, In the central Arctic Ocean the formation of clouds and their properties are sensitive to the availability of cloud condensation nuclei (CCN). The vapors responsible for new particle formation (NPF), potentially leading to CCN, have remained unidentified since the first aerosol measurements in 1991. Here, we report that all the observed NPF events from the Arctic Ocean 2018 expedition are driven by iodic acid with little contribution from sulfuric acid. Iodic acid largely explains the growth of ultrafine particles (UFP) in most events. The iodic acid concentration increases significantly from summer towards autumn, possibly linked to the ocean freeze-up and a seasonal rise in ozone. This leads to a one order of magnitude higher UFP concentration in autumn. Measurements of cloud residuals suggest that particles smaller than 30 nm in diameter can activate as CCN. Therefore, iodine NPF has the potential to influence cloud properties over the Arctic Ocean., The Swedish Polar Research Secretariat (SPRS) provided access to the I/B Oden and logistical support in collaboration with the U.S. National Science Foundation. This work was supported by the Swiss National Science Foundation (grant no. 200021_169090), the Swiss Polar Institute, the BNP Paribas Swiss Foundation (Polar Access Fund 2018), the Knut-and Alice-Wallenberg Foundation within the ACAS project (Arctic Climate Across Scales, project no. 2016.0024), the Bolin Centre for Climate Research (RA2), the Swedish Research Council (project nos. 2018-05045 and 2016-05100) and by the Natural Environment Research Council (grant no. NE/R009686/1). J.S. holds the Ingvar Kamprad Chair, sponsored by Ferring Pharmaceuticals. A.S.-L. acknowledges the funding from the European Research Council Executive Agency under the European Union’s Horizon 2020 Research and Innovation program (Project ‘ERC-2016-COG 726349 CLIMAHAL’). Funding of the expedition AO2018 was provided to Caroline Leck by the NSF and SPRS’s Cost sharing Understanding Arctic Ocean 2018 Reg. no. 2018-113, and by the Swedish Research Council projects nos. 824-2013-222 and 2016-03518. We are grateful to Xu-Cheng He (University of Helsinki, Finland) for the insightful discussions about iodine NPF and for helping with the calibration of the nitrate CIMS. We would like to thank Michael Wheeler and Richard Leaitch (Environment and Climate Change Canada) for lending the CVI inlet and the technical support and Silvia Henning (TROPOS, Germany) for lending and calibrating the cloud condensation nuclei counter. We also thank Heini Wernli (ETH Zürich, Switzerland) for calculating the air mass backtrajectories, Barbara Brooks (National Centre for Atmospheric Science, U.K.) for processing the FSSP data and John Prytherch (Stockholm University, Sweden) for processing temperature and wind speed data. We acknowledge the CABM network for providing the iodine measurement at Alert and CFS Alert for maintaining infrastructure for Alert location.

An oxidation system in which iodic acid (HIO3) is used as an oxidant in the presence of N-hydroxyphthalimide (NHPI) permitted the selective hydroxylation of tertiary C-H bonds and the lactonization of carboxylic acids containing a tertiary carbon center. These reactions are operationally simple and proceed under metal-free conditions using commercially available reagents, thus offering an ideal tool for the efficient oxidation of C-H bonds at tertiary carbon centers.

Etching characteristics of lattice-matched GaInP/GaAs/GaInNAsSb heterostructures by aqueous solutions of iodic acid (HIO3) and hydrochloric acid (HCl) is reported. The study aims at optimization of mesa fabrication process involved in the development of III‒V multijunction solar cells. The effects of temperature, agitation, etchant composition, and illumination on the etching selectivity are investigated. Varying the etchant composition and agitation rate at room temperature results in various mesa sidewall morphologies, ranging from rough surfaces and significant undercut to smoother sidewall profiles with only minor undercut. Especially, the undercut emerging in the GaInNAsSb junction, as well as in the AlInP layers, was observed for several etching conditions. Increasing the etching temperature also caused an unwanted increase in the selectivity, whereas reducing the temperature below the room temperature enhanced remarkably the formation of smooth morphology. Illumination during the etching resulted in a severe undercut in the GaAs junction, due to an increased selectivity caused by photoetching. This points out the need of controlled illumination condition to avoid unwanted reactions in wet etching of such multijunction structures. The etching process resulting in the best morphology was used for electrical isolation of triple-junction GaInP/GaAs/GaInNAsSb solar cells. The good photovoltaic performance exhibited by these devices proves the suitability of the nonselective etch process in developing multijunction solar cells. publishedVersion

f-element-bearing iodate compounds are a large family mostly synthesized by hydrothermal reactions starting with actinide/lanthanide ions and iodic acid or iodate salt. In this work, we introduce melting periodic acid flux as a new reaction medium and provide a safe way for single-crystal growth of a series of new f-element iodate compounds including UO2(IO3)2·H2O (1), UO2(IO3)2(H2O)·HIO3 (2), α-Th(IO3)2(NO3)(OH) (3), β-Th(IO3)2(NO3)(OH) (4), and (H3O)9Nd9(IO3)36·3HIO3 (5). The structures of these compounds deviate from those afforded from hydrothermal reactions. Specifically, compounds 1 and 2 exhibit pillared structures consisting of uranyl pentagonal bipyramids and iodate trigonal pyramids. Compounds 3 and 4 represent two new thorium iodate compounds that are constructed from subunits of thorium dimers. Compound 5 exhibits a flower-shaped trivalent lanthanide iodate structure with HIO3 molecules and H3O+ cations filled in the channels. The aliovalent replacement of f elements in 5 is available from a h...

A new polymorph of iodic acid,δ-HIO3, synthesized via aerosol spray pyrolysis was characterized with powder X-ray diffraction and its crystal structure was solved. We find that a previously misidentified phase of I4O9hydrate is in fact a new polymorph of HIO3, which crystalizes in the orthorhombic space groupP212121.

The possibility of applying paratellurite, iodic acid, and lithium iodate crystals in acousto-optics in the THz range has been investigated. The transparency windows of these crystals and their refractive indices in the THz range have been determined. The acousto-optic figures of merit of these materials are calculated for different acousto-optic interaction geometries.

The effect of processing liquids on particle surface hydration and subsequent reactivity of mixtures containing aluminum (Al) with different oxidizing agents was investigated. Recently, polar processing liquids were shown to significantly increase the surface hydration layer on Al particles and effect the reactivity of Al combined with polytetrafluoroethylene (PTFE). Processing mixtures of Al and PTFE using hexane (e.g., a non-polar liquid) limited surface hydration and produced significantly lower flame speeds than the same mixture processed in isopropanol (e.g., a polar liquid). Increased surface hydroxyl concentration was linked to higher exothermic behavior within a pre-ignition reaction (PIR) which may contribute to higher overall flame speed. This study extends the previous analysis toward assessing the influence of processing liquid on reactivity of aluminum with other oxidizing agents, specifically CuO, MoO 3 and I 2 O 5 . Results from DSC analysis show no PIR kinetics associated with Al and CuO or MoO 3 , and Al+ CuO showed no difference in reactivity as a function of processing liquid. But, MoO 3 FTIR shows modified surface structures after treatment in a polar solvent. Correspondingly, Al + MoO 3 processed in polar solvent exhibited increased flame speed by 19% when compared to Al + MoO 3 processed in a non-polar liquid. For Al + I 2 O 5 , water in polar processing liquids produces various hydrated states of iodic acid (i.e., HIO 3 and HI 3 O 8 ). Changing the hydration state of I 2 O 5 significantly impacts reactivity. Results from this study confirm that carrier fluid used to process Al with metal oxides can also alter the surface structure of the metal oxide, thereby promoting greater reactivity with Al. A polar carrier fluid not only modifies the surface of Al but also hydration sensitive metal oxides such as MoO 3 and correspondingly promotes greater reactivity.

Iodic acid (HIO3) was exploited as the effective source to build an artificial solid-electrolyte interphase (SEI) on the surface of Li anode. On one hand, HIO3 is a weak solid-state acid and can be easily handled to remove most ion-insulating residues like Li2CO3 and/or LiOH from the pristine Li surface; on the other hand, both the products of LiI and LiIO3 resulted from the chemical reactions between Li metal and HIO3 are reported to be the ion-conductive components. As a result, the lower voltage polarization and impedance, longer cycling lifetime and higher Coulombic efficiency have been successfully achieved in the HIO3-treated Li–Li and Li–Cu cells. By further using the HIO3-treated Li anode into practical Li–S batteries, the impressive results also have been obtained, with average discharge capacities of 719 mAh g–1 for 200 cycles (0.2 C) and 506 mAh g–1 for 500 cycles (0.5 C), which were better than the Li–S batteries using the pristine Li anode (552 and 401 mAh g–1, respectively) under the same co...

High iodine containing oxides are of interest as biocidal components in energetic applications requiring fast exothermic reactions with metallic fuels. Aerosol techniques offer a convenient route and potentially direct route for preparation of small particles with high purity, and are a method proven to be amenable and economical to scale-up. Here, we demonstrate the synthesis of various iodine oxide/iodic acid microparticles by a direct one-step aerosol method from iodic acid. By varying temperature and humidity, we produced near phase pure δ-HIO3, HI3O8, and I2O5 as determined by X-ray diffraction. δ-HIO3, a previously unknown phase, was confirmed in this work. In addition, scanning electron microscopy was used to examine the morphology and size of those prepared iodine oxide/iodic acid particles and the results show that all particles have an irregularly spherical shape. Thermogravimetric/differential scanning calorimetry measurement results show that HIO3 dehydrates endothermically to HI3O8, and then to I2O. I2O5 decomposes to I2 and O2.

The pure gold dissolution has been explored in (dilute) chloric, bromic, or iodic acid (HXO3, X = Cl, Br, I) aqueous solution containing abundant halide ions at 60 °C. It has been found that mixtures between sodium chlorate and HCl (NaClO3 + HCl ⇆ HClO3 + NaCl) in 20 mL are effective media for the dissolution of pure gold-wire (99.95 %, ca. 20 mg, 0.25 mm diameter). The gold-wire dissolution is much more enhanced by HBr than HCl in NaClO3 solution. At 0.50 mol dm-3 NaClO3, for instance, log (k/s-1) values are -5.11 and -3.40 (ca. 50-fold increase) for 1.0 mol dm-3 HCl and HBr, respectively, where “pseudo” first-order dissolution rate constants (k/s-1) have been evaluated by the changes in the mass of gold-wire. In HClO3 solution containing abundant halide ions (X- = Cl-, Br-), the Au metal should be oxidized mainly by X2 to be AuX4-, where X2 is produced by the oxidizing power from HClO3, just as dilute HNO3 ( ~ 5 mol dm-3).

Iodic acids are widely studied in atmospheric and biological applications but their inherent hydrophilic properties introduce complexities that affect their functionality and reactivity. We have shown that iodic acid (HIO3) dehydrates directly into iodine pentoxide (I2O5) in contradiction to the generally accepted multi-step dehydration mechanism where HIO3 dehydrates into HI3O8 first, then dehydrates into I2O5. The generally accepted mechanism is used to determine the concentration of iodic acid by TGA and is only valid for special conditions. The revised mechanism allows for the determination of concentrations of iodic acids under all conditions, and the more specific conditions where the accepted mechanism is valid are shown. The determination of concentration of iodic acid with the revised dehydration mechanism is dependent on assumptions of residual water and initial concentration of HI3O8. The validity of these assumptions is established by studying the absorption and hydration behavior of I2O5 from atmospheric water. These results will have an impact on the handling and use of iodine.

An efficient iodic acid-triggered radical cyclization of alkenes with N-hydroxyphthalimide (NHPI) is described. This operationally simple method was conducted under metal- and catalyst-free conditions, producing the precious aminooxylated 3,3-disubstituted 2-oxindoles in good to high yields. Green and readily available HIO3 was used as a sole and safe initiator, making this protocol highly advantageous.

Aerosol Formation Iodine species are one of only a handful of atmospheric vapors known to make new aerosol particles, which play a central role in controlling the radiative forcing of climate. He et al. report experimental evidence from the CERN Cosmics Leaving Outdoor Droplets, or CLOUD, chamber demonstrating that iodic acid and iodous acid rapidly form new particles and can compete with sulfuric acid in pristine regions. Science , this issue p. [589][1] [1]: /lookup/doi/10.1126/science.abe0298

Various primary and secondary benzylic alcohols were efficiently oxidized to aromatic aldehydes and aromatic ketones with iodic acid in DMF at 60 °C for 2 h and with iodic acid in the presence of TEMPO (5 mol %) in DMF at room temperature, respectively. The former method was effective for the oxidation of sterically hindered alcohols at 60 °C and the latter method was effective for the oxidation of less sterically hindered alcohols at room temperature.

The exact mechanisms for new particle formation (NPF) under different boundary layer conditions are not known yet. One important question is whether amines and sulfuric acid lead to efficient NPF in the atmosphere. Furthermore, it is not clear to what extent highly oxidized organic molecules (HOMs) are involved in NPF. We conducted field measurements at a rural site in central Germany in the proximity of three larger dairy farms to investigate whether there is a connection between NPF and the presence of amines and/or ammonia due to the local emissions from the farms. Comprehensive measurements using a nitrate chemical ionization–atmospheric pressure interface time-of-flight (CI-APi-TOF) mass spectrometer, a proton-transfer-reaction mass spectrometer (PTR-MS), particle counters and differential mobility analyzers (DMAs), as well as measurements of trace gases and meteorological parameters, were performed. We demonstrate here that the nitrate CI-APi-TOF is suitable for sensitive measurements of sulfuric acid, amines, a nitrosamine, ammonia, iodic acid and HOMs. NPF was found to correlate with sulfuric acid, while an anti-correlation with RH, amines and ammonia is observed. The anti-correlation between NPF and amines could be due to the efficient uptake of these compounds by nucleating clusters and small particles. Much higher HOM dimer (C19/C20 compounds) concentrations during the night than during the day indicate that these HOMs do not efficiently self-nucleate as no nighttime NPF is observed. Observed iodic acid probably originates from an iodine-containing reservoir substance, but the iodine signals are very likely too low to have a significant effect on NPF.

Iodine pentoxide (I 2 O 5 ) is typically synthesized by dehydration of iodic acid such that the produced material inherently includes hydrated iodic acid species that facilitate further water absorption when exposed to ambient environments. This is a detrimental property for I 2 O 5 powder used in energetic systems. A dry-approach for synthesizing I 2 O 5 with either crystalline (nano C I 2 O 5 ) or amorphous (nano A I 2 O 5 ) structure was used for this study and compared to the commercially available material. This synthesis approach enabled isolation of the microstructure as a variable to better understand water absorption behavior of I 2 O 5 and associated reactivity. Material characterization included BET, SEM, TEM, and XRD as well as equilibrium analyses using DSC and TGA along with flame speeds. Results show that nano C I 2 O 5 reacts less with atmospheric water and has a more anhydrous behavior than the crystalline I 2 O 5 powder commercially available. The nano A I 2 O 5 also produced a distinct pre-ignition reaction (PIR) and evidence for smaller PIRs are shown for all mixtures of Al with I 2 O 5 . These properties along with increased specific surface area of the nano C I 2 O 5 and nano A I 2 O increased reactivity and enhanced combustion with Al when compared with commercial I 2 O 5 .

An efficient, green, rapid multitasking protocol for the selective C-5 substitution of 2-aminothiazole using iodic acid and aqueous PEG-400 was developed. The method found suitable for C-5 substitution i.e. iodination and thiocyanation of 2-amino thiazole using iodine and ammonium thiocyanate respectively. Iodic acid was found to be a good oxidant and aqueous PEG-400 as green reaction solvent.

The iodine-arsenous acid (Roebuck), iodide-iodate (Dushman), and iodate-arsenous acid reactions have been studied simultaneously by a stopped-flow technique by monitoring the absorbance-time profiles at the isosbestic point of the I2/I3(-) system (468 nm). Using the well-accepted rate coefficients of iodine hydrolysis, we have proven that iodine is the kinetically active species of the iodine-arsenous acid reaction. Strong iodide inhibition of this system is explained by a rapidly established equilibrium between iodine and arsenous acid to produce an iodide ion, a hydrogen ion, and a short-lived intermediate H2AsO3I, which is shifted far to the left. Taking into consideration the generally accepted kinetic model of the Dushman reaction where I2O2 plays a key role to account for all of the most important observations in this subsystem and a sequence of simple formal oxygen-transfer reactions between arsenous acid and iodic acid as well as iodous acid and hypoiodous acid, we propose a 13-step comprehensive kinetic model, including seven rapidly established equilibria with only six fitted parameters, that is able to explain all of the most important characteristics of the kinetic curves of all of the title systems both individually and simultaneously.

The possibility of experimentally obtaining backward collinear isotropic acousto-optic interaction based on bulk ultrasonic waves and terahertz electromagnetic waves is considered. The magnitudes of the acousto-optic figure of merit and the corresponding acoustic frequencies are calculated for the basic crystallographic axes in germanium and iodic acid crystals. The acousto-optic parameters of both crystals are compared.

A program for calculating characteristics of acousto-optic interaction in biaxial crystals is developed and used to analyze light diffraction by ultrasound in an iodic acid crystal. Crystal cuts with maximum acousto-optic figures of merits are found. It is shown that in the region of the optical axes the frequency dependences of the Bragg angles under anisotropic diffraction are substantially different from those in uniaxial crystals.

A crystalline aluminum iodate acid salt has been synthesized from aluminum particles dissolved in iodic acid solution. The precipitate from solution is aluminum iodate hexahydrate [Al(H2O)6](IO3)3(HIO3)2, as confirmed by X-ray diffraction (XRD) analysis. The method of synthesis first dissolves iodine oxide in water, creating an IO3− solution with pH

We synthesized pure Zn(IO3)2 structures employing a chemical method and characterized them using the electron microscopy to understand the effect of acidity on particle size. The average particle size of Zn(IO3)2 sample was measured to be 46 nm. We analyzed the results of X-ray diffraction characterization, scanning electron microscopy (SEM), UV–vis absorbance and FTIR spectra. Structural, mechanical, electronic, and related linear optical properties of monoclinic Zn(IO3)2 have been explored using density functional theory (DFT) methodology based on pseudo-potential plane wave method approach. The electronic structure shows that Zn(IO3)2 has an indirect band gap of 2.59 eV. This value is underestimated, due to DFT shortcoming, compared to the experimental optical band gap that was extracted from the absorbance curve and evaluated at 3.53 eV. The dielectric functions and associated optical responses spectra were calculated. The present zinc iodate could be considered as a promising material for optoelectronics and nonlinear optics applications.

The reinvestigation of the EDA–HIO3–H2O system using a different stoichiometric ratio gives rise to a new iodate salt C2H10N2(IO3)2.HIO3 denoted as EBIMIA. In this study, we reported the structural properties of ethylenediammonium bis iodate mono iodic acid using X-ray powder and single crystal diffraction at room temperature. The Hirshfeld and the potential energy surface analysis reveal that I⋯O and N–H⋯O are the most noticeable interactions that took place inside the crystal and contribute to the cohesion and stability of the synthesized compound. The DSC measurement shows that this iodate salt undergoes two structural phase transitions, the first occurs at T = 290 K while the second occurs at T = 363 K. However, the dielectric analysis confirms only the second transition because it lies in the studied temperature domain 338–413K. Besides, the impedance data obey a circuit model consisting of a parallel combination of a bulk resistance and CPE. The frequency dispersion of the conductivity follows Jonscher’s law and the charge carrier transport may be interpreted using the correlation barrier hopping mechanism (CBH). Finally, the electronic properties and the vibrational analysis of this novel iodate salt are studied using DFT and compared to the experimental data given by the FT-IR, Raman and UV–visible spectroscopies.

In coastal regions, intense bursts of particles are frequently observed with high concentrations of iodine species, especially iodic acid (IA). However, the nucleation mechanisms of IA, especially in polluted environments with high concentrations of sulfuric acid (SA) and ammonia (A), remain to be fully established. By quantum chemical calculations and atmospheric cluster dynamics code (ACDC) simulations, the self-nucleation of IA in clean coastal regions and that influenced by SA and A in polluted coastal regions are investigated. The results indicate that IA can form stable clusters stabilized by halogen bonds and hydrogen bonds through sequential addition of IA, and the self-nucleation of IA can instantly produce large amounts of stable clusters when the concentration of IA is high during low tide, which is consistent with the observation that intense particle bursts were linked to high concentrations of IA in clean coastal regions. Besides, SA and A can stabilize IA clusters by the formation of more halogen bonds and hydrogen bonds as well as proton transfers, and the binary nucleation of IA-SA/A rather than the self-nucleation of IA appears to be the dominant pathways in polluted coastal regions, especially in winter. These new insights are helpful to understand the mechanisms of new particle formation induced by IA in clean and polluted coastal regions.

In this study, the production of particulate films of iodine (V) oxides is investigated. The influence that sonication and solvation of suspended particles in various alcohol/ketone/ester solvents have on the physical structure of spin or drop cast films is examined in detail with electron microscopy, powder x-ray diffraction, and UV-visible absorption spectroscopy. Results indicate that sonicating iodine oxides in alcohol mixtures containing trace amounts of water decreases deposited particle sizes and produces a more uniform film morphology. UV-visible spectra of the pre-cast suspensions reveal that for some solvents, the iodine oxide oxidizes the solvent, producing I2 and lowering the pH of the suspension. Characterizing the crystals within the cast films reveal their composition to be primarily HI3O8, their orientations to exhibit a preferential orientation, and their growth to be primarily along the ac-plane of the crystal, enhanced at higher spin rates. Spin-coating at lower spin rates produces laminate-like particulate films versus higher density, one-piece films of stacked particles produced by drop casting. The particle morphology in these films consists of a combination of rods, plates, cubes, and rhombohedra structure.

The formation of oriented nanostructures of iodic acid (HIO3) on track-etched membranes has been studied. The study has shown that the method of forced filtration of supersaturated crystallization solutions through track membrane pores can be used to grow needlelike faceted microcrystals that have the cross size and preferential growth direction corresponding to those of the pores.

Metal iodates with a lone-pair containing I(V) in an asymmetric coordination geometry can form a diversity of unusual structures, including non-centrosymmetric (NCS) structures with promising second-order nonlinear optical (NLO) properties. They have wide transparent wavelength regions (0.4–12 μm), large second harmonic generation (SHG) coefficients (>10 × KDP for many iodates) and high optical-damage thresholds (4–50 GW cm −2 ) as well as good thermal stability (usually >400 °C). In this review, the structures and second-order NLO properties of metal iodates will be discussed. Under reaction media with a high concentration of iodic acid, the iodate groups can be condensed into binuclear or polynuclear iodate anions, these compounds are able to display large SHG responses. The introduction of other lone pair containing cations into the iodate system is also an effective strategy to design new NCS materials. The combination of d 0 transition-metal cations with iodate groups afforded a large number of NCS metal iodates with anionic structures ranging from 0D clusters, 1D chains, 2D layers to 3D networks. These NCS materials can display excellent second-order NLO properties when the polarizations from both types of the asymmetric units are aligned properly. As for the iodates of d 8 -transition metal ion with a square planar TMO 4 geometry, the cis TM(IO 3 ) 4 unit in which the four iodate groups are located at the same side of the TMO 4 plane favors the formation of NCS structures whereas the trans - one in which the four iodate groups being located at both sides of the TMO 4 square plane prefers to a centrosymmetric structure. NCS structures with good SHG properties can also be found in other mixed metal iodate systems.

Background: Tranexamic acid and etamsylate drugs belong to a group of antifibrinolytics. Tranexamic Acid (TRA) is the most potent antifibrinolytic lysine analogue used in a broad spectrum of peri-and postoperative interventions and bleeding disorders. The administration of TRA is associated with a reduction in bleeding due to its inhibitory effect on clot breakdown (fibrinolysis). Etamsylate (ESL) is a haemostatic agent that appears to maintain the stability of the capillary wall and correct abnormal platelet adhesion. It is given for the prophylaxis and control of haemorrhages from small blood vessels. Objective: Two simple and sensitive spectrophotometric methods are described for the determination of tranexamic acid (TRA) and etamsylate (ESL) drugs in pure form and pharmaceutical preparations. Materials and Methods Method (A) is used for the determination of TRA and based on condensation reaction of the primary amino group of TRA with salicylaldehyde reagent (SA) (Schiff base formation) producing a yellow coloured product which is measured spectrophotometrically at 400 nm. Method (B) is utilized for the determination of ESL and based on the oxidation-reduction reaction of ESL using iodic acid (HIO3). The liberated iodine was extracted in chloroform and the absorbance of the red coloured product is measured spectrophotometrically at 510 nm. For method A and B, different variables affecting the reactions were studied and optimized. Results: Under the optimum conditions, linear relationships with good correlation coefficients 0.9989 and 0.9959 were found between the absorbance and the concentration of the drug in the range from 5 to 500 and 2.5 to 275 μg mLG 1 for ESL and TRA drugs, respectively. The limit of detection (μg mLG 1 ), limit of quantification (μg mLG 1 ) and molar absorptivity (L molG 1 cmG 1 ) values were found to be 1.442, 4.80 and 5.39×10 2 for TRA drug and 2.20, 7.25 and 3.0×10 2 for ESL drug, respectively. Conclusion: The method was applied for determination of the investigated drugs in tablets. The method was validated and can be suggested for routine analysis of both drugs.

International audience; In this paper, the mechanism of the HOIO2 + OH → products reaction is investigated using quantum chemistry tools. Two pathways are considered: HOIO2 + OH → OIO2 + H2O and HOIO2 + OH → OIO + H2O2. The potential energy surfaces are calculated at the CCSD(T)/CBS(D,T)//B3LYP/aug-cc-pVTZ level of theory. The OH radical was found to attack iodic acid from either the frontside (TSHabs) or the topside (TSOHabs), subsequently leading to H- or OH-transfer channels. Reaction enthalpies and standard Gibbs free reaction energies at 298 K are provided. The values indicate that only the HOIO2 + OH → OIO2 + H2O channel is exothermic and exergonic. Theoretical prediction of the kinetic parameters is performed within the framework of the transition state theory (TST) and variational transition state theory (VTST). The rate constants (in cm³ molecule–1 s–1) for temperatures from 250 to 2500 K are kHabs(T) = 1.76 × 10–22T2.39 exp(−3.5 (kJ mol–1)/RT) and kOHabs(T) = 3.16 × 10–21T2.57 exp(−96.2 (kJ mol–1)/RT). The HOIO2 + OH overall reaction is significantly dominated by the HOIO2 + OH → OIO2 + H2O channel for tropospheric temperatures. The main outcomes of this work are as follows: (i) The lifetime of iodic acid toward its removal by OH radicals is extremely long (1336 years), enabling its transportation to different locations around the Earth (marine, polar, and continental), as confirmed by recent field measurements; other possible loss pathways under clear sky (gas phase) and cloudy (aqueous phase) conditions could reduce its atmospheric lifetime. (ii) The thermochemical properties of the OIO2 radical are provided: ΔfH298 K° = 168.3 kJ mol–1, S298 K° = 301.45 J mol–1 K–1, and Cp(300 K) = 65.82 J mol–1 K–1.

Alfred Ditte (1843–1908), a student of Henri Sainte-Claire Deville, carried on a large number of important researches in the areas of mineralogy, chemistry, and thermodynamics, in particular, vanadium and its compounds, properties of aluminum, alumina, and aluminates, the Leclanché cell, dissociation mechanism, and iodic acid and iodates.

A facile and efficient way of generating oxygen vacancies in visible light activated one-dimensional iodine doped TiO2 photocatalysts was first reported in this work. A two-step hydrothermal synthesis was used to synthesize TiO2 nanomaterials modified by iodic acid (HIO3) as a dopant. Detailed analysis was conducted to illustrate the intrinsic doping/reaction mechanisms of iodic acid in the modification of the TiO2 matrix. The phase and structure evolution were deduced from X-ray diffraction (XRD), Raman, and scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) was conducted to analyze the generation of oxygen vacancies and the formation of I–O–Ti bonds in the TiO2 lattice. Multi-valences of iodine, due to the reduction of iodic acid, facilitated the generation of oxygen vacancies and 3d state Ti3+ species in the TiO2 lattice. The visible light absorption and enhanced photocatalytic activity of the TiO2 nanomaterials were attributed to existing oxygen vacancies, iodine multi-valences in I–O–Ti bonds, and 3d state Ti3+ sites in the TiO2 lattice. The photocatalytic degradation efficiency under visible light (λ > 400 nm) followed a pseudo first-order kinetic model. Rutile nanowires using a two-step synthesis method produced the highest methylene blue (10 mg L−1) degradation rate constant, Kap, of 7.92 × 10−3 min−1 compared to other synthesized nanomaterials. The Kap value obtained was an order of magnitude greater than commercial P25 (3.87 × 10−4 min−1) and pristine TiO2 nanowires (4.18 × 10−4 min−1). The iodine doped TiO2 photocatalysts can be used in TiO2/light irradiation advanced oxidation processes (AOPs) in water treatment using sunlight or a visible light source, rather than an ultraviolet irradiation source.

Catalysis of the oxidative processes by iodoarenes has become a promising direction in synthesis. The mechanism, involving the well-known isolable hypervalent iodine species, is generally limited to aromatic iodides, since the corresponding aliphatic species are normally highly unstable. Nevertheless, in this work catalytic amount of several primary, secondary or tertiary iodoalkanes were found to promotes the α-tosyloxylation of a range of ketones with RSO3H, including aliphatic sulfonates. The process, was found to proceed through the oxidative breakdown of the iodoalkane to an inorganic catalytic species (likely IO− or IO2−), thus falling within the previously described catalysis using molecular iodine or inorganic iodides. The catalyst eventually becomes deactivated through the precipitation of an iodine overoxidation product, the structure of which was solved ab initio from the powder diffraction data as a hitherto unreported phase of the iodic acid (HIO3).