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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.

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.

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.

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.

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.

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.

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...

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.

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.

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

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 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 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 Ritter-type amination of a tertiary C–H bond using iodic acid (HIO3) as an oxidant, in the presence of N-hydroxyphthalimide (NHPI) is reported. This operationally simple method is conducted under metal-free conditions, is scalable, and efficiently provides valuable α-tertiary amine derivatives.

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.

The structures, energetics, and thermodynamic properties of HIO 3 isomers (HOOOI, HOOIO, HOIO 2 , and HIO 3 ) have been computed using CCSD(T)/CBS theoretical method. The spin orbit corrections (SOC) have also been evaluated for the each iodine-containing molecule. The SOC value decreases as the iodine valence increases within the molecule. The results revealed that HOIO 2 was the most stable form and that HOOOI was the next most stable isomer. The standard enthalpies of formation at 298 K have been derived from IO + HO 2 and OH + OIO dissociation pathways. At the CCSD(T)/CBS level on B3LYP geometries, the recommended Δ f H ° 298K is (−95.4 ± 0.3) kJ mol −1 for HOIO 2 , and its computed S ° 298K and C p (300 K) values are respectively 339.12 and 75.28 J mol −1 K −1 . Further, monohydrated and dihydrated complexes of iodic acid have been investigated using DFT and wavefunction methods. Three and six mono- and di-hydrated complexes, respectively, have been identified. The hydrogen bonded complexes (HOIO 2 _1wa and HOIO 2 _2wa) are the lowest lying structures. The thermodynamics of dihydrates have been calculated from the total hydration of iodic acid (HOIO 2 + 2H 2 O). Mono- and di-hydration of iodic acid is a favored process at tropospheric and ambient conditions with the formation of HOIO 2 _1wa and HOIO 2 _2wa at T ⩽ 310 K. The positive Gibbs free energies at high temperatures indicate that gas-phase iodic acid would not be present in a hydrated form inside the nuclear containment building of a pressurized water reactor.

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 .

This article describes simple and efficient method for the iodination of different aromatic amines, hydroxy aromatic aldehydes, hydroxy acetophenones and phenols using iodine and iodic acid in ethanol as a solvent. Notable advantages include mild reaction condition, no need of catalyst, short reaction time, simple practical procedure, giving excellent yield of the product.

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.

A combination of iodic acid and potassium iodide has been used for trimethylsilylation of alcohols and phenols in the presence of HMDS and iodination of aromatic amines. The reactions occur very rapidly to provide the products in good to high yields in dichloromethane at room temperature while the use of toxic and corrosive molecular iodine is avoided.

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.

1,1′-Methylenebis(1H-pyrazole) and 1,1′-methylenebis(3,5-dimethyl-1H-pyrazole) reacted with iodine in the presence of iodic acid to give the corresponding 4,4′-diiodo derivatives. Polycondensation of the latter with p-diethynylbenzene led to the formation of oligomeric compounds. 1,1′-Methylenebis(4-iodo-1H-pyrazoles) were converted into 4,4′-diethynyl derivatives by the Sonogashira and reverse Favorskii reactions, and their oxidative polycondensation in the presence of copper(I) chloride in pyridine also gave oligomeric products with a molecular weight exceeding 9000.

A variety of ortho hydroxy substituted aromatic carbonyl compounds were regioselectively mono or diiodinated with iodine and iodic acid in excellent yields.

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.

Bismuth iodate was synthesized by precipitation from bismuth nitrate and iodic acid. The powder was dissolved in dilute nitric acid and single crystals were obtained by slow evaporation at 70°C. Bi(IO3)3 crystallizes in the monoclinic system, space group P21/n (N° 14), a = 8.8882(2) A, b = 5.9445(2) A, c = 15.2445(5) A, β = 97.064(1) A. BiO9 polyhedra are edge-connected forming chains parallel to the b axis; these chains are linked through (IO3) groups forming layers parallel to (101). The 3D framework is designed by linking these layers through long I–O bonds. DSC analysis shows a remarkable thermal stability.

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.

A variety of ortho-hydroxy substituted aromatic carbonyl compounds were regioselectively iodinated with iodine and iodic acid in excellent yields.

K2S2O8, iodic acid or Selectfluor can be used as oxidants to afford ortho-hydroxylated benzoates selectively.

(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.

A simple, mild, and efficient method for the iodination of various aromatic amines, hydroxy aromatic aldehydes, hydroxy acetophenones and phenols is presented (34 examples).

A variety of substrates is regioselectively iodinated under mild conditions in short reaction times.

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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.

The structure of the solud solution Li1-xHxIO3 (x = 0.33) is determined at room temperature by X-ray single crystal and neutron powder diffraction. The space group is found to be P63 like α-LiIO3. Hydrogen atoms are in general positions with the occupation factor 0.33 and form weak bonds with neighbouring oxygens. The structure is briefly compared with that of α-LiIO3.

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.

Selective electrophilic iodination of 2-acetyl-1-naphthol was achieved using iodine and iodic acid in combination with grinding at room temperature under solvent-free conditions to yield 1-(1-hydroxy-4-iodo-naphthalen-2-yl)-ethanone. Grinding mode of reactions has not only of interest from economical point of view, in many cases they also offer considerable advantages in terms of yield, mild reaction conditions, selectivity and simplicity of reaction procedure.

(Difluoro)methoxyoxo iodine(V) (IF2(O)OCH3), the methyl ester of the unknown difluoro iodic acid (IF2(O)OH), was obtained by the reaction of methoxytrimethyl silane with iodine pentafluoride. IF2(O)OCH3 crystallizes orthorhombic in the space group Pbca with a = 7.605(1) A, b = 7.360(1) A, c = 15.017(1) A, and eight formula units per unit cell. The final R indices [I > 2 sigma(I)] are R1 = 0.0264 and wR2 = 0.0516. Additionally, IF2(O)OCH3 was characterized by its vibrational spectra and quantum mechanical calculations were performed.

The halogens fluorine, chlorine, bromine, and iodine are reactive nonmetals and hence are found in nature as chemical compounds and not in the free elemental state. These elements and their compounds have similar chemical characteristics but with gradations of several properties. The reactions of halogen cations, the commercial sources of iodide, and their evaluation by chromatographic techniques have been described (see Additional Readings, Chapter 7).

Based on Landolt's reaction between iodic acid and sulfite to produce iodine, a method has been developed for the high-yield iodination of tyrosine to form diiodotyrosine without significant formation of monoiodotyrosine. The use of sulfite as reductant for iodic acid cannot be effectively replaced by citric or oxalic acid under the reaction conditions.

The hydrolysis (or disproportionate) of molecular iodine to form iodate and iodide ions has been studied by emf measurements over the temperature range, 3.8 to 209.0°C. The interpretation of these results required a knowledge of the formation constant for triiodide ion and the acid dissociation constant of iodic acid, both of which were measured as a function of temperature. The resulting thermodynamic data have been incorporated into a general computer model describing the hydrolysis equilibria of iodine as a function of initial concentration, pH and temperature.

The iodine concentration behaviour of the title reaction has been investigated. Production and consumption rates under various conditions are reported. Some mechanistic details are suggested.

The hydrogen peroxide-iodic acid-manganese(II)-malonic acid oscillating system has been investigated. The reaction has been shown to be photosensitive and to be inhibited by chloride ion. In the absence of light oscillations of ca. 200 mV were obtained in the initial stages of the reaction. An “activation energy” (Ew) of 72.7±2 kJ/mol was obtained.