Search

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.

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...

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.

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.

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

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 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.

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.

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).

The exact mechanisms for new particle formation (NPF) under different boundary layer conditions are not known yet. One important question is if amines and sulfuric acid lead to efficient NPF in the atmosphere. Furthermore, it is not clear to what extent highly oxidized organic molecules (HOM) 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 if 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. It is shown that the nitrate CI-APi-TOF is suitable for sensitive measurements of sulfuric acid, amines, a nitrosamine, ammonia, iodic acid and HOM. 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 HOM do not efficiently self-nucleate as no night-time 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 doped titanium dioxide has been successfully prepared by simple hydrolysis of tetrabutyl titanate in the presence of iodic acid. The adopted method allowed for the production of spherical iodine doped titaniun dioxide nanoparticles with varied amount of iodine content. Analysis by X-ray diffraction, Raman, transmission electron microscopy as well as UV–vis DRS revealed that titanium dioxide nanostructures were doped with iodine which existed in two different valence states I 5+ and I − . The iodine in the form of I 5+ is believed to have doped into the lattice whereas I − was well dispersed on the surface of TiO 2 probably as iodine adducts hence rendering it to be highly absorbing in visible light region. The I-TiO 2 exhibited improved photocatalytic activity toward degradation of acid orange 7 (AO7), methyl orange (MO) and 2,4-dichlorophenol (2,4-DCP) under visible light over the pristine TiO 2 prepared by the same method. High catalytic properties are attributed to iodine doping which led to high specific surface area, absorption in visible region as well as alleviation of charge carrier recombination. The most probable route undertaken in the degradation of AO7 is through indirect oxidation by the hydroxyl radicals.

Zirconium and iodine co-doped titanium dioxide (Zr–I–TiO 2 ) was prepared by the hydrolysis of tetrabutyl titanate, premixed with zirconium nitrate in an iodic acid aqueous solution, followed by calcination in air. The structure and properties of the resultant catalyst powders were characterized by X-ray diffraction, the Brunauer–Emmett–Teller method, X-ray photoelectron spectroscopy, transmission electron microscopy, and UV–vis absorption spectroscopy. The catalytic activity of the catalyst was evaluated by monitoring the photocatalytic decolorization of methyl orange under visible light irradiation. The results showed that the activities of Zr–I–TiO 2 catalysts were higher than that of TiO 2 doped with iodine alone (I–TiO 2 ), and the optimal doping concentration in the Zr–I–TiO 2 calcined at 400 °C was determined to be about 0.05 (molar ratio of Zr:Ti). In addition, the photocatalytic activity of Zr–I–TiO 2 calcined at 400 °C was found to be significantly higher than that calcined at 500 or 600 °C. Based on the physico-chemical characterization, we concluded that the role of zirconium on the I–TiO 2 surface is to increase the number of reactive sites by generating a small crystal size and large surface area. The inhibition of electron–hole pair recombination, by trapping photo-generated electrons with Zr 4+ , did not contribute markedly to the improved photocatalytic activity of Zr–I–TiO 2 .

Green, mild and efficient iodination of hydroxylated aromatic aldehydes and ketones using iodine and iodic acid in the solid-state by grinding under solvent-free conditions at room temperature. This method provides several advantages such as environmentally friendly, short reaction times, high yields, non-hazardous and simple work-up procedure.

This work focuses on the structure, morphology and photocatalytic performance of pure TiO2 and IO3--doped TiO2 nanoparticles. The photocatalytic activity IO3--doped TiO2 nanoparticles in the decomposition of monocrotophos (MCP) are illustrated and discussed in comparison with standard Degussa P-25. Furthermore, IO3--doped TiO2 showed high relative photonic efficiency compared with some of the commercial photocatalysts. The obtained results show a significant dependence of the degradation performance on IO3--doped TiO2 nanoparticles’s structural, morphological and composition properties. In particular, smaller particle size, large surface area and the formation of mixed phases of TiO2 by the addition of iodic acid have a beneficial influence to enhance the photocatalytic activity of IO3--doped TiO2 nanoparticles for the degradation as well as mineralization of MCP.

2-Pentafluorophenyl hydrazono alkylphosphonates and phosphine oxides 1 are converted to the corresponding phosphorylated azoalkenes 2 in excellent yields (86–94%) upon treatment with a suspension of iodic acid in dichloromethane at room temperature.

Using high-level ab initio calculations and excited state ab initio molecular dynamics simulations, we show that hydrated iodic acids release hydrogen radicals and/or hydrogen molecules as well as iodine radicals upon excitation. Its photoreaction process involving charge transfer to the solvent takes place in four steps: 1) hydration of the acid, 2) charge transfer to water upon excitation of hydrated acid, 3) detachment of the neutral iodine atom, and 4) detachment of the hydrogen radical. The iodine detachment process from excited hydrated hydro-iodic acids is exothermic and the detachment of hydrogen radicals from hydrated hydronium radicals is spontaneous if the initial kinetic energy of the cluster is high enough to get over the activation barrier of the detachment. The complete release of the radicals can be understood in terms of kinetics. This study shows how the hydrogen and halogen radicals are dissociated and released from their hydrated acids. Simple experiments corroborate our predicted mechanism for the release of hydrogen molecules from iodic acid in water by ultraviolet light.

We determined apparent molar volumes Vϕ at 298.15 ⩽ (T/K) ⩽ 368.15 and apparent molar heat capacities Cp,ϕ at 298.15 ⩽ (T/K) ⩽ 393.15 for aqueous solutions of HIO3 at molalities m from (0.015 to 1.0) mol · kg−1, and of aqueous KIO3 at molalities m from (0.01 to 0.2) mol · kg−1 at p = 0.35 MPa. We also determined Vϕ at the same p and at 298.15 ⩽ (T/K) ⩽ 368.15 for aqueous solutions of KI at m from (0.015 to 7.5) mol · kg−1. We determined Cp,ϕ at the same p and at 298.15 ⩽ (T/K) ⩽ 393.15 for aqueous solutions of KI at m from (0.015 to 5.5) mol · kg−1, and for aqueous solutions of NaIO3 at m from (0.02 to 0.15) mol · kg−1. Values of Vϕ were determined from densities measured with a vibrating-tube densimeter, and values of Cp,ϕ were determined with a twin fixed-cell, differential temperature-scanning calorimeter. Empirical functions of m and T were fitted to our results for each compound. Values of Ka, ΔrHm, and ΔrCp,m for the proton ionization reaction of aqueous HIO3 are calculated and discussed.

Chemoselective oxidation of various alcohols was proceeded by using a catalytic amount of KBr in the presence of periodic acid or iodic acid and wet SiO 2 under mild and heterogeneous conditions with moderate to excellent yields.

The article describes the use of iodic acid in combination with catalytic amounts of tetraethylammonium bromide (TEAB) as a mild and alternative reagent system for oxidation of sulfides to sulfoxides. The salient features of the developed system are room‐temperature reactions, short reaction times, and compatibility with a wide range of functional groups.

The 127 I NQR, IR absorption and Raman spectra of impurity-doped and mixed lithium iodate Li 1− x H x IO 3 crystals grown from water solutions with different LiIO 3 /HIO 3 ratios were investigated depending on the content of the impurity hydrogen x . The NQR results suggested that, at small concentration of doping iodic acid x x 1− x H x IO 3 are formed.

The electrochemical oxidation of iodic acid and lithium iodate to periodate, a powerful oxidation agent for dialdehyde carbohydrates, was investigated for various anode materials (viz. boron-doped diamond, lead and platinum). Galvanostatic electrolyses and voltammetric experiments were carried out for iodic acid, iodic acid–lithium iodate and lithium iodate–lithium hydroxide solutions. It was found that the maximum periodate current efficiency for boron-doped diamond and lead electrodes is about 0.6 and for platinum electrodes almost zero. A reaction mechanism for the oxygen and periodate formation on the boron-doped diamond electrode in acid solution has been proposed. For a boron-doped diamond electrode in the high potential range the charge transfer coefficient and the exchange current density for the oxygen evolution are 0.14×10 −4 and 4×10 −4 A m −2 , respectively.

The mechanism of the hypercoordination of the iodine atom and its role in the crystal packing of iodic acid were examined within the topological analysis of the experimental electron density function.

Ln(IO3)3 (Ln = Ce, Nd, Eu, Gd, Er, Yb) polycrystals were hydrothermally synthesized using lanthanide nitrate or lanthanide oxide and iodic acid as precursors. X-ray diffraction was used to characterize the crystal structures of the Ln(IO3)3 products. Scanning electron microscopy was carried out to observe the microscopic morphologies. The lattice spacings were studied by high-resolution transmission electron microscopy and selected area electron diffraction. We evaluated the photocatalytic efficiency by decomposing methyl orange dye under ultraviolet light irradiation, and the Ln(IO3)3 products show excellent photocatalytic properties. To rule out the effect of photosensitization, 2,4-dichlorophenol was also photodegraded. As one of the key factors of photocatalysis, ultraviolet–visible diffuse reflectance spectra of the Ln(IO3)3 samples were also studied, and all products have strong absorption in the ultraviolet region.

Durch Umsetzung von Iodsaure mit Oleum bei 210 °C wurde erstmals HIS2O8 dargestellt. Nach der Rontgenstrukturanalyse (monoklin, P21/c, a = 1172,0(2), b = 625,7(2), c = 956,0(2) pm, β = 106,50(2), Z = 4, 1083 unabhangige Reflexe, R1 = 0,037, wR2 = 0,103) sind jeweils eine Sulfat und Hydrogensulfatgruppe uber Iod verbruckt, so das IO2-Brucken resultieren. Die neue Heteropolysaure kann formal als durch Kondensation der hypothetischen Iodsaure (III), HIO2, mit Schwefelsaure entstanden angesehen werden. Synthesis and Constitution of HIS2O8 Novel HIS2O8 has been obtained by reacting iodic acid and oleum at 210 °C. According to the results of a X-ray structure determination (monoclinic, P21/c, a = 1172.0(2), b = 625.7(2), c = 956.0(2) pm, β = 106.50(2), Z = 4, 1083 reflections, R1 = 0.037, wR2 = 0.103) iodine is connecting a sulfate and a hydrogensulfate group, thus forming IO2 bridges. This can be regarded as a condensation of hypothetical iodic acid (III), HIO2, with sulfuric acid.

Durch Umsetzung von Iodsaure in Oleum bei 195°C wurden erstmals Einkristalle von Iodyldisulfat erhalten. Nach der Rontgenstrukturanalyse (monoklin, P21/a, a = 885,0(2), b = 1037,3(2), c = 915,8(2) pm, β = 94,75(2)°, Z = 4, 1466 unabhangige Reflexe, R1 = 0,033, wR2 = 0,063) liegen dimere Iodylkationen (IO2) vor, die uber Disulfatgruppen zu polymeren Strangen verknupft sind. Auffallig ist eine nahezu gleichmasige Verteilung der IO-Abstande uber den gesamten Bereich von starken intramolekularen Bindungen (174 pm) bis zu intermolekularen Kontakten vom van der Waals Typ (> 300 pm). The First Crystal Structure Analysis of an Iodyl Compound Single crystals of (IO2)2S2O7 were obtained for the first time by reacting iodic acid and oleum at 195°C. According to the results of a X-ray structure determination (monoclinic, P21/a, a = 885.0(2), b = 1037.3(2), c = 915.8(2) pm, β = 94.75(2)°, Z = 4, 1466 diffractometer data, R1 = 0.033, wR2 = 0.063), (IO2)2S2O7 contains dimeric iodyl cations (IO2), which are connected by disulfate groups thus forming polymeric strands. Strikingly, the IO-distances range almost continously from 174 pm (strong intramolecular bonds) to 300 pm (van der Waals contacts).

Etching profiles at mask edges on (100) InP are obtained in acidic FeCl{sub 3} containing solutions under uniform illumination and in iodic acid solutions in darkness. For both etching systems, the results of microscopic etching near mask edges are compared to the macroscopic etching behavior of individual crystallographic faces. In the case of photoetching by FeCl{sub 3}, a difference in profile shape is observed between p- and n-type samples, associated with the fact that the photoetching occurs by an electrochemical mechanism. At p-type samples, the slowest etching face [i.e., the (111) face] is revealed whereas at n-type, profiles with very rough bottoms are observed. A tentative interpretation for this phenomenon is proposed. No difference in profile shape is found between p- and n-type in the iodic acid solution, which operates through a chemical mechanism. An anisotropic microscopic etching behavior is however observed. A model, in which the presence of a thin oxide layer on the InP plays a crucial role, can explain this etching behavior.

A variety of aromatic amines are oxidized to their corresponding quinones in excellent yields by supported iodic acid under microwave irradiation and solvent free conditions.

Iodine oxide particles are known to nucleate in the marine boundary layer where gas phase molecular iodine and organoiodine species are produced by macroalgae. These ultra-fine particles may then grow through the condensation of other materials to sizes where they may serve as cloud condensation nuclei. There has been some debate over the chemical identity of the initially nucleated particles. In laboratory simulations, hygroscopic measurements have been used to infer that they are composed of insoluble I2O4, while elemental analysis of laboratory generated particles suggests soluble I2O5 or its hydrated form iodic acid, HIO3 (I2O5·H2O). In this paper we explore the response of super-micron sized aqueous iodic acid solution droplets to varying humidity using both Raman microscopy and single particle electrodynamic traps. These measurements reveal that the propensity of an iodic acid solution droplet to crystallise is negligible on drying to ~0% relative humidity (RH). On applying mechanical pressure to these droplets they shatter in a manner consistent with an ultra-viscous liquid or a brittle glass. Water retention in amorphous material at low RH is important for understanding the hygroscopic growth of aerosol particles and uptake of other condensable material. Subsequent water uptake between 10 and 20% RH causes their viscosity to reduce sufficiently that the cracked droplets flow and merge. The persistence of iodic acid solution in an amorphous state, rather than a crystalline state, suggests they will more readily accommodate other condensable material and are therefore more likely to grow to sizes where they may serve as cloud condensation nuclei. On increasing the humidity to ~90% the mass of the droplets only increases by ~20% with a corresponding increase in radius of only 6%, which is remarkably small for a highly soluble material. We suggest that the small growth factor of aqueous iodic acid solution droplets is consistent with the small aerosol growth factors observed in previous experiments.

Iodine oxide particles are known to nucleate in the marine boundary layer where gas phase molecular iodine and organoiodine species are produced by macroalgae. There has been some debate over the chemical identity of these particles. Hygroscopic measurements have been used to infer that they are composed of insoluble I2O4, while elemental analysis of laboratory generated particles suggests soluble I2O5 or its hydrated form iodic acid, HIO3 (I2O5 · H2O). In this paper we explore the response of super-micron sized aqueous iodic acid solution droplets to varying humidity using both Raman microscopy and single particle electrodynamic traps. These measurements reveal that the propensity of an iodic acid solution droplet to crystallise is negligible on drying to ~0% relative humidity (RH). On applying mechanical pressure to these droplets they shatter in a manner consistent with an ultra-viscous liquid or a brittle glass, but subsequent water uptake between 10 and 20% RH causes their viscosity to reduce sufficiently that the cracked droplets flow and merge. The persistence of iodic acid solution in an amorphous state, rather than a crystalline state, suggests they will more readily accommodate other condensable material and are therefore more likely to grow to sizes where they may serve as cloud condensation nuclei. On increasing the humidity to ~90% the mass of the droplets only increases by ~20% with a corresponding increase in radius of only ~6 %, which is remarkably small for a highly soluble material. We suggest that the small growth factor of aqueous iodic acid solution droplets is consistent with the small aerosol growth factors observed in field experiments.

(C5H5NH)2MO2F4 (M = Mo and W) and C5H5NHIO2F2 have been synthesized at room temperature by the reaction of molybdic, tungstic or iodic acid, respectively, with pyridinium poly(hydrogen fluoride). These complexes have been characterized by chemical analyses, H-1 nmr and infrared spectroscopy.

ESR studies of single crystals of H5IO6 ?-irradiated at 77 K reveal two paramagnetic centers, one exhibiting 11 hyperfine components in the free-spin region and the other revealing two broad features at higher field. The radical which is in the free-spin region has a low hyperfine coupling and is identified as (HO)5IO{minus sign, dot below}OI(OH)+ 5 (dimer hole center). The spin density of the unpaired electron on the iodine 5s and 5p orbitals is found to be 0.014. The center at the higher field, however, has a larger coupling and is identified as H5IO- 6 (electron gain center). The spin density for this center has been found to be 0.34. The temperature variation studies reveal that both the centers are unstable above 120 K. ? 1994.

A new reagent system, a combination of iodic acid and sodium nitrite has been investigated for oxidative coupling of N,N-disubstituted anilines. A facile para-selective coupling occurs to give benz...

The etch rate of the (100)-face of n- and p-type InP and that of the (111)- and (111)-faces of n-InP in aqueous iodic acid solutions was measured as a function of several variables using a flow-cell setum. The electrochemical behavior of HIO 3 at the n- and p-InP electrode was investigated cathodically and anodically, in darkness and unter illumination. The limiting photocurrent, both cathodically for p-type as anodically for n-type InP, was found to be enhanced when adding HIO 3 to the different electrolyte solution;possible electrode reaction mechanisms are discussed

Crystal data : Be(IO 3 ) 2 .2HIO 3 .6H 2 O, orthorhombic, Pnam, a=7.842(1), b=8.613(1), c=24.407(2) A, V=1648.5(5) A 3 , Z=4, T=292 K, R=0.030 for 3018 observed reflections with I>3σ(I). The iodic acid and iodate groups are arranged in along the b-axis corrugated slabs with the HIO 3 molecules at the crests and troughs. The channels between them are extended along the a-axis and filled with Be(H 2 O) 4 2+ cations and water molecules. All the structural fragments take part in a H-bonding scheme

International audience

Phosphorus trifluoride and thiophosphoryl fluoride both react smoothly with iodine monochloride at room temperature to form dichlorotrifluorophosphorane. The oxidants, nitryl chloride, iodic acid and periodic acid undergo reduction to nitrosyl chloride and iodine respectively, oxidising the phosphorus trifluoride to phosphoryl fluoride. The nitrite salts of sodium and potassium also undergo reduction at elevated temperatures(200°C) with phosphorus trifluoride and then react further with the formed phosphoryl fluoride to yield the corresponding monofluorophosphates of sodium and potassium.

Soret coefficients of aqueous phosphoric acid and aqueous iodic acid are determined conductimetrically at 25 °C. As the molality of phosphoric acid drops from 0.05 toward 0.00 mol kg−1, the enthalpy of transport jumps from 2 to 15 kJ mol−1. For iodic acid, a stronger electrolyte, the corresponding increase is smaller, from 12 to 17 kJ mol−1. Equations are developed for the enthalpy of transport of 1:1 weak electrolytes. The equations are used to evaluate the reactive enthalpy of transport and the intrinsic enthalpies of transport of the ionized and molecular forms of phosphoric and iodic acids. Equating the enthalpies of transport of the acid molecules and the acid anions provides estimates of single-ion enthalpies of transport. Thermal diffusion measurements are reported for potassium dihydrogen phosphate and potassium iodate to help interpret the results. Keywords: thermal diffusion, enthalpy of transport, Soret coefficients, weak electrolytes, phosphoric acid, iodic acid.

The direct intercalation of iodic acid into the layered uranyl iodate, UO2(IO3)2(H2O), has been observed to yield UO2(IO3)2(H2O)·2HIO3 in crystalline form. This is the first example of this type of reaction with iodic acid.

From solutions of chromium(III) perchlorate and periodic acid, single crystals of gamma-HIO3 were obtained and characterized by single-crystal X-ray diffraction, Raman spectroscopy and thermal analysis. The compound crystallizes in the orthorhombic crystal system, space group Pbca (a = 563.92, b = 611.10, c = 1507.16 pm). The structure is built up by dimers (HIO3)(2), which are formed by hydrogen bonds. The crystals are metastable and transform into the stable modification, alpha-HIO3, within a couple of weeks.

The hydrothermal reaction of a 2 3 9 Pu(IV) stock solution in the presence of iodic acid and 1 M KOH produces reddish-brown single crystals of (PuO 2 ) 2 (IO 3 )(OH) 3 . The structure consists of two-dimensional layers forming in the ac plane and is the first single-crystal structure of plutonium(VI) connected through hydroxide anions. The additional linkage of plutonium centers is completed through iodate ligands.