Simple Inorganic Molecules Research Articles

Sulphur ion implantation into O2, CO, and CO2 ices: Implications for the formation of sulphur-bearing molecules in the Kuiper Belt

Previous experimental work has systematically investigated the radiolytic sulphur chemistry arising as a result of the implantation of reactive sulphur ions into various oxygen-bearing molecular ices (e.g., H2O, CO2) so as to better understand the surface chemistry of the Galilean moons of Jupiter, where sulphur ions are sourced from the giant Jovian magnetosphere. However, significantly less attention has been paid to analogous sulphur chemistry occurring under conditions relevant to the Kuiper Belt, where sulphur ions supplied by the solar wind may implant into the surfaces of icy bodies that are rich in volatile oxygen-bearing molecular ices such as O2, CO, or CO2. This paper presents the results of a study on the implantation of 290–400 keV S+ ions into pure O2, CO, and CO2 ices under temperature, pressure, radiation dose, and ice deposition conditions relevant to the Kuiper Belt, with a particular focus on the potential synthesis of simple inorganic sulphur-bearing molecules (e.g., SO2, OCS, CS2). Experiments involving CO2 ices were also performed at higher temperatures more typically associated with the Galilean moon system so as to determine whether there exist any differences in the chemistry resulting from the implantation of reactive sulphur ions in these two regions of the Solar System. Our results constitute the first systematic investigation of solid-phase sulphur chemistry in the Kuiper Belt mediated by the sulphur ion component of the solar wind, and thus represent an important step forward in our understanding of the astrochemical processes occurring in the outermost depths of the Solar System.

NaHCO3‐induced porous PbI2 enabling efficient and stable perovskite solar cells

AbstractDriven by their many unique features, perovskite solar cells (PSCs) have become one of the most promising candidates in the photovoltaic field. Two‐step preparation of perovskite film is advantageous for its higher stability and reproducibility compared to the one‐step method, which is more suitable for practical application. However, the incomplete conversion of the dense lead iodide (PbI2) layer during the sequential spin‐coating of formamidinium/methylammonium (FA+/MA+) organic amine salts severely affect the performance of PSCs. Herein, sodium bicarbonate (NaHCO3) is used to induce the formation of porous PbI2, which facilitates the penetration of the FA+/MA+ ions and the formation of a perovskite film with high crystallinity and large grain microstructure. Meanwhile, the introduction of Na+ not only improves the energetic alignment of the PSC, but also increases the conductivity via p‐doping. As a result, the optimized NaHCO3‐modified PSC achieves a champion power conversion efficiency of 24.0% with suppressed hysteresis. Moreover, the significant reduction in defect density and ion migration as well as a mild alkaline environment enhance the stability of device. The unencapsulated NaHCO3‐modified PSCs maintain over 90% of their original efficiency upon storage in ambient air (30%–40% relative humidity) for 2160 h. We have demonstrated an ingenious strategy for controlling the quality of perovskite and improving the performance of device by low‐temperature foaming of simple inorganic molecules of NaHCO3.image

Studying the influence of different parameters on the electrochemical oxidation of tannery dyes using a Ti/IrO2-SnO2-Sb2O5 anode

Electrochemical oxidation directly converts organic compounds into simple inorganic molecules like carboxylic acids, H2O and CO2, and it is considered an efficient method for treating highly polluted wastewater. In this study, MMO (Ti/IrO2-SnO2-Sb2O5) was tested for the electrochemical oxidation of mono-azo (Violet RL), diazo (Green A), and tetra-azo (Brown DR) dyes used in the tannery industry. The study focused on understanding the effect of different parameters such as supporting electrolyte, dye concentration, azo dye type, pH, and current density, on the performance of the electrochemical oxidation process of individual dyes and their mixture. Under 50 mM of Na2SO4 at pH 3 and j = 50 mA cm−2 close to 100% electrochemical oxidation was achieved when 50 mg L−1 Violet RL solution was tested. Using the best conditions of 35 mM NaCl + 25 mM Na2SO4 supporting electrolyte at pH 3.0 and 50 mA cm−2 current density, a rapid and complete discoloration of a mixture of the three azo dyes at 80 mg L−1 each, with about 92% COD decay and low energy consumption, with an acceptable low ECCOD value of 0.08 kWh (g COD)−1. To assess the complete level of dye oxidation, the evolution of nontoxic short-chain carboxylic acids was evaluated.

Performance of Ti/RuO2-IrO2 electrodes and comparison with BDD electrodes in the treatment of textile wastewater by electro-oxidation process

Electrochemical oxidation (EO) technology, which may directly reduce refractory contaminants into simple inorganic molecules like H2O and CO2, is an efficient approach for treating high-concentration wastewater. Boron doped diamond (BDD) electrodes has been extensively researched and used to degrade organic contaminants from real textile wastewater. In this study, two-dimensionally stable anodes, Ti/RuO2-IrO2, were produced and compared with BDD electrodes for the treatment of textile wastewater. This study focuses on the optimization of the produced electrode under different pH and current densities. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis revealed that the oxide coating on the Ti plate’s surface was effectively produced. The EO process parameters were optimized using central composite design (CCD) under response surface methodology (RSM), with total organic carbon (TOC), chemical oxygen demand (COD), and color removals as responses and pH, current density, and reaction time as control variables. The analysis of variance (ANOVA) revealed good coefficients of determination (R2) values of.0.90, indicating that the second-order regression model matched the experimental data satisfactorily. In optimized conditions, pH 4 was shown to have the maximum effectiveness for both electrodes. The best treatment efficiency was obtained by applying an 800 A/m2 current for 5 h, taking into account the time component in the different current values employed. BDD had a color, TOC, and COD removal of 93%, 75%, and 48%, respectively, whereas Ti/RuO2-IrO2 had a color, TOC, and COD removal of 88%, 62%, and 41%, respectively. In addition, the toxicity of water treated with the BDD electrode was found to be lower, whereas the toxicity of water treated with the Ti/RuO2-IrO2 electrode was found to be higher.

Stereochemical dependence of substituent γ-effects in the 19 F NMR shielding constants.

The substituent α-, β-, and γ-effects of the elements of the second and third periods on 19 F NMR chemical shifts are evaluated including the establishment of stereochemical dependence of γ-effect, the latter particularly important in stereochemical studies of fluorine-containing compounds. Benchmark calculations performed for a series of 32 simple inorganic fluorine-containing molecules demonstrated a markedly good correlation between calculated and experimental fluorine chemical shifts characterized by a mean absolute error of 22.5ppm in the range of about 900 ppm, which corresponds to a 2.5% error in the percentage terms.

Towards recognizing the mechanisms of effects evoked in living organisms by static magnetic field. Numerically simulated effects of the static magnetic field upon simple inorganic molecules.

Background: Recognizing effects of static magnetic field (SMF) of varying flux density on flora and fauna is attempted. For this purpose, the influence of static magnetic field upon molecules of water, nitrogen, ammonia, carbon dioxide, methane and molecular oxygen was studied. Methods: Computations of the effect of SMF of 0.1, 1, 10 and 100T flux density were performed in a computer vacuum involving advanced computational methods. Results: It was shown that SMF polarizes molecules depending on applied flux density but it neither ionizes nor breaks valence bonds. Three-molecular conglomerates of very dense packing form systems involving supramolecular orbitals. These orbitals deteriorate with an increase in the SMF flux density developing highly polarized structures. They are entirely different from these originally formed out of SMF. Conclusions: Small inorganic molecules commonly present in living organisms of flora and fauna can substantially influence functioning of those organisms when exposed to SMF.

Chemi-Ionization Reactions and Basic Stereodynamical Effects in Collisions of Atom-Molecule Reagents.

A new theoretical method, developed by our laboratory to describe the microscopic dynamics of gas-phase elementary chemi-ionization reactions, has been applied recently to study prototype atom–atom processes involving reactions between electronically excited metastable Ne*(3P2,0) and heavier noble gas atoms. Important aspects of electronic rearrangement selectivity have been emphasized that suggested the existence of two fundamental microscopic reaction mechanisms. The distinct mechanisms, which are controlled by intermolecular forces of chemical and noncovalent nature respectively, emerge under different conditions, and their balance depends on the collision energy regime investigated. The present paper provides the first step for the extension of the method to cases involving molecules of increasing complexity, whose chemi-ionization reactions are of relevance in several fields of basic and applied researches. The focus is here on the reactions of Ne* with simple inorganic molecules as Cl2 and NH3, and the application of the method discloses relevant features of the reaction microscopic evolution. In particular, this study shows that the balance of two fundamental reaction mechanisms depends not only on the collision energy and on the relative orientation of reagents but also on the orbital angular momentum of each collision complex. The additional insights so emphasized are of general relevance to assess in detail the stereodynamics of many other elementary processes.

Autocatalytic Networks at the Basis of Life's Origin and Organization.

Life is more than the sum of its constituent molecules. Living systems depend on a particular chemical organization, i.e., the ways in which their constituent molecules interact and cooperate with each other through catalyzed chemical reactions. Several abstract models of minimal life, based on this idea of chemical organization and also in the context of the origin of life, were developed independently in the 1960s and 1970s. These models include hypercycles, chemotons, autopoietic systems, (M,R)-systems, and autocatalytic sets. We briefly compare these various models, and then focus more specifically on the concept of autocatalytic sets and their mathematical formalization, RAF theory. We argue that autocatalytic sets are a necessary (although not sufficient) condition for life-like behavior. We then elaborate on the suggestion that simple inorganic molecules like metals and minerals may have been the earliest catalysts in the formation of prebiotic autocatalytic sets, and how RAF theory may also be applied to systems beyond chemistry, such as ecology, economics, and cognition.

Combined IR and XPS characterization of organic refractory residues obtained by ion irradiation of simple icy mixtures

Context. Multi-year laboratory experiments have demonstrated that frozen icy mixtures containing simple organic and inorganic molecules (such as H2O, N2, CH4, CO, CO2, C2H6, etc.), if exposed to a flux of energetic ions or UV photons, give rise to new more complex molecules at low temperatures (10–50 K). A fraction of the new synthesized molecules is volatile while the remaining fraction is refractory and therefore it is preserved after the warm-up of the substrate to room temperature. Moreover, a part of the refractory material is formed during the annealing to room temperature, when molecules and radicals into the processed ice become mobile and react to form non-volatile molecules. By means of similar mechanisms, complex organic materials may be formed on the icy surfaces of some objects in the outer solar system, such as trans-Neptunian objects, comets and some satellites of the giant planets: in fact the interaction with solar wind and solar flares ions, solar photons and galactic cosmic rays could produce more refractory materials, analogous to those produced in the laboratory. In some cases, the materials thus synthesized may contain functional groups considered relevant to the pre-biotic chemistry in the hypothesis that interplanetary dust particles, comets and meteoroids contributed to seed the early Earth with the building blocks of life. Aims. The aim of this work is to investigate the chemical similarities and differences between some organic residues left over after ion bombardment (200 keV H+) of different ice mixtures followed by subsequent warm up under vacuum to room temperature. Methods. Seven organic residues have been prepared in our laboratory following a procedure involving the proton irradiation of seven different icy mixtures and their warm-up to room temperature. All the organic samples were characterized by FTIR spectroscopy with measurements performed in situ, in the ultra-high vacuum condition preventing any sample degradation. Three of them were selected to be characterized by XPS spectroscopy as well. Results. Among the organic residues presented in this paper, only those containing nitrogen and carbon exhibit the multi-component band centred at 2200 cm−1. This multi-component band presents interest from the astrobiological point of view due to its attribution to nitriles (–C≡N) and isonitriles (–N≡C). Our results demonstrate that this band is present in the IR spectra of organic nitrogen residues regardless the use of oxygen-bearing species in the icy mixture. This finding is of interest since the 2200 cm−1 band has been observed in some extraterrestrial samples (micro-meteorites) collected in the Antarctica.

The molecular chemistry of diffuse and translucent clouds in the line-of-sight to Sgr B2: Absorption by simple organic and inorganic molecules in the GBT PRIMOS survey

The 1–50 GHz PRebiotic Interstellar MOlecular Survey (PRIMOS) contains ~50 molecular absorption lines observed in clouds located in the line-of-sight to Sgr B2(N). The line-of-sight material is associated with diffuse and translucent clouds located in the Galactic center, bar, and spiral arms in the disk. We measured the column densities and estimate abundances, relative to H2, of 11 molecules and additional isotopologues observed in this material. We used absorption by optically thin transitions of c-C3H2 to estimate the molecular hydrogen columns, and argue that this method is preferable to more commonly used methods. We discuss the kinematic structure and abundance patterns of small molecules including the sulfur-bearing species CS, SO, CCS, H2CS, and HCS+; oxygen-bearing molecules OH, SiO, and H2CO; and simple hydrocarbon molecules c-C3H2, l-C3H, and l-C3H+. Finally, we discuss the implications of the observed chemistry for the structure of the gas and dust in the ISM. Highlighted results include the following. First, whereas gas in the disk has a molecular hydrogen fraction of 0.65, clouds on the outer edge of the Galactic bar and in or near the Galactic center have molecular fractions of 0.85 and >0.9, respectively. Second, we observe trends in isotope ratios with Galactocentric distance; while carbon and silicon show enhancement of the rare isotopes at low Galactocentric distances, sulfur exhibits no trend with Galactocentric distance. We also determine that the ratio of c-C3H2/c-H13CCCH provides a good estimate of the 12C/13C ratio, whereas H2CO/H213CO exhibits fractionation. Third, we report the presence of l-C3H+ in diffuse clouds for the first time. Finally, we suggest that CS has an enhanced abundance within higher density clumps of material in the disk, and therefore may be diagnostic of cloud conditions. If this holds, the diffuse clouds in the Galactic disk contain multiple embedded hyperdensities in a clumpy structure, and the density profile is not a simple function of AV.

Detection of simple inorganic and organic molecules over Cu-decorated circumcoronene: a combined DFT and QTAIM study.

Nowadays graphene materials have attracted a considerable attention because of their potential utilization as gas sensors, biosensors, or adsorbents. Doping or decorating the graphene surface with transition metals can significantly tune its electronic properties and chemical reactivity. Circumcoronene, being a polyaromatic hydrocarbon composed of 19 benzene rings, can be used as a model system of a tiny graphene quantum dot. The adsorption of a set of small molecules (water, hydrogen peroxide, methanol, ethanol, and oxygen) over the copper-decorated circumcoronene was theoretically investigated using density functional theory (DFT) and Bader's quantum theory of atoms in molecules (QTAIM). Following the obtained B3LYP energies, the adsorption of O2 and the chemisorption of H2O2 were found to be energetically the most favorable, with energetic outcomes of -3.6 eV and -3.7 eV, respectively. Moreover, an H2O2 molecule was decomposed during the chemisorption on the Cu atom to form a neutral Cu(OH)2 molecule. Changes in the electronic structure of the studied systems, in particular the oxidation of copper, after the adsorption were investigated within the framework of QTAIM (e.g., charges, bond critical points, and delocalization indices) and partial density of states (PDOS) analysis. The results of this study suggest the suitability of the Cu-decorated graphene materials as adsorbents and/or gas sensors in practical applications.

Cavitation-Induced Synthesis of Biogenic Molecules on Primordial Earth.

Despite decades of research, how life began on Earth remains one of the most challenging scientific conundrums facing modern science. It is agreed that the first step was synthesis of organic compounds essential to obtain amino acids and their polymers. Several possible scenarios that could accomplish this step, using simple inorganic molecules, have been suggested and studied over the years. The present study examines, using atomistic reactive molecular dynamics simulations, the long-standing suggestion that natural cavitation in primordial oceans was a dominant mechanism of organic molecule synthesis. The simulations allow, for the first time, direct observation of the rich and complex sonochemistry occurring inside a collapsing bubble filled with water and dissolved gases of the early atmosphere. The simulation results suggest that dissolved CH4 is the most efficient carbon source to produce amino acids, while CO and CO2 lead to amino acid synthesis with lower yields. The efficiency of amino acid synthesis also depends on the nitrogen source used (i.e., N2, NH3) and on the presence of HCN. Moreover, cavitation may have contributed to the increase in concentration of NH3 in primordial oceans and to the production and liberation of molecular O2 into the early atmosphere. Overall, the picture that emerges from the simulations indicates that collapsing bubbles may have served as natural bioreactors in primordial oceans, producing the basic chemical ingredients required for the beginning of life.

RNA networks at the origins of life

The origin of life has often been viewed as the advent of a single self-replicating molecular species, such as RNA. We propose a somewhat different approach in that a network of co-operating molecules could have kick-started life. This view has both theoretical and experimental support. The foundations for life, as we understand it on our planet, began some 4.5 billion years ago with the formation of the Earth1 and by 4.0 billion years ago evidence for the presence of life existed. Within that timeframe, physical and chemical processes would have produced increasingly more complex interactions, moving from simple inorganic molecules to biopolymers capable of replication and variation. In order to answer the question of how life originated and to even understand what life is, empirical proof-ofconcept simple abiotic pathways demonstrating these transitions are needed. In this article, we discuss how networks of molecules, rather than single replicating molecular species, is an emerging view that may unlock some longstanding problems in the origins field.

ON THE FORMATION OF AMIDE POLYMERS VIA CARBONYL–AMINO GROUP LINKAGES IN ENERGETICALLY PROCESSED ICES OF ASTROPHYSICAL RELEVANCE

ABSTRACT We report on the formation of organic amide polymers via carbonyl–amino group linkages in carbon monoxide and ammonia bearing energetically processed ices of astrophysical relevance. The first group comprises molecules with one carboxyl group and an increasing number of amine moieties starting with formamide (45 u), urea (60 u), and hydrazine carboxamide (75 u). The second group consists of species with two carboxyl (58 u) and up to three amine groups (73 u, 88 u, and 103 u). The formation and polymerization of these linkages from simple inorganic molecules via formamide und urea toward amide polymers is discussed in an astrophysical and astrobiological context. Our results show that long chain molecules, which are closely related to polypeptides, easily form by energetically processing simple, inorganic ices at very low temperatures and can be released into the gas phase by sublimation of the ices in star-forming regions. Our experimental results were obtained by employing reflectron time-of-flight mass spectroscopy, coupled with soft, single photon vacuum ultraviolet photoionization; they are complemented by theoretical calculations.

A Comprehensive Review of Aliphatic Hydrocarbon Biodegradation by Bacteria.

Hydrocarbons are relatively recalcitrant compounds and are classified as high-priority pollutants. However, these compounds are slowly degraded by a large variety of microorganisms. Bacteria are able to degrade aliphatic saturated and unsaturated hydrocarbons via both aerobic and anaerobic pathways. Branched hydrocarbons and cyclic hydrocarbons are also degraded by bacteria. The aerobic bacteria use different types of oxygenases, including monooxygenase, cytochrome-dependent oxygenase and dioxygenase, to insert one or two atoms of oxygen into their targets. Anaerobic bacteria, on the other hand, employ a variety of simple organic and inorganic molecules, including sulphate, nitrate, carbonate and metals, for hydrocarbon oxidation.

Soups & SELEX for the origin of life.

The theory of evolution quickly brought up the most fascinating question in biology: the origin of life. How did life emerge? The biggest challenge in this endeavor to understand how life could have emerged without a controller is to unravel the chemical processes that made the synthesis of complex molecules containing information possible. Already at high school I was totally caught by Oparin's hypothesis that simple unicellular organisms evolved from simple organic molecules, which in turn originated from simple inorganic molecules present in the early atmosphere of our planet. Oparin and Haldane coined the idea of “primordial soup” experiments. For my “Matura” (that is the name of the exam you do in Austria, when you finally leave high school) I got Stanley Miller's famous primordial soup experiments as question. I just now realize that ever since SOUP & SELEX experiments are the ones I find most seminal for shaping our view of the world. I still consider these experiments as the breakthrough in biology of the 20th century because it opened up a whole new field clearly suggesting that one day it might be possible to understand how life emerged. Until the discovery of microorganisms by Louis Pasteur, fermentation by microorganisms was thought to be the product of spontaneous generation. Until Eduard Buchner demonstrated that fermentation could occur outside a living organism, in a test tube, it was the belief that only living cells were able to catalyze biochemical reactions. When in 1897 Bucher reported that a cell-free extract from yeast was able to ferment sugar, the field of biochemistry was invented and the analysis of chemical reactions taking place in living cells became accessible. There have been several theoretical approaches to the emergence of life as a self-replicating system, whereby the most essential part of all these concepts is the idea that complex systems can evolve from simple compounds without an external controller. This was indeed a revolutionary thought! As Erwin Schrodinger pointed out in 1944, it looks like living organisms bypass the second law of thermodynamics because they are able to evolve to complex systems out of disordered compounds ignoring Maxwell's Demon. Manfred Eigen, Leslie Orel and Stuart Kauffmann coined theoretical backgrounds on which chemists could develop experimental set ups. Combinatorial events of simple chemical reactions could lead to stably replicating populations of increasing complexity.

The RNA world and the origin of metabolic enzymes.

An RNA world has been placed centre stage for explaining the origin of life. Indeed, RNA is the most plausible molecule able to form both a (self)-replicator and to inherit information, necessities for initiating genetics. However, in parallel with self-replication, the proto-organism had to obtain the ability to catalyse supply of its chemical constituents, including the ribonucleotide metabolites required to replicate RNA. Although the possibility of an RNA-catalysed metabolic network has been considered, it is to be questioned whether RNA molecules, at least on their own, possess the required catalytic capacities. An alternative scenario for the origin of metabolism involves chemical reactions that are based on environmental catalysts. Recently, we described a non-enzymatic glycolysis and pentose phosphate pathway-like reactions catalysed by metal ions [mainly Fe(II)] and phosphate, simple inorganic molecules abundantly found in Archaean sediments. While the RNA world can serve to explain the origin of genetics, the origin of the metabolic network might thus date back to constraints of environmental chemistry. Interestingly, considering a metal-catalysed origin of metabolism gives rise to an attractive hypothesis about how the first enzymes could have formed: simple RNA or (poly)peptide molecules could have bound the metal ions, and thus increased their solubility, concentration and accessibility. In a second step, this would have allowed substrate specificity to evolve.

Reactions of V4O10+ cluster ions with simple inorganic and organic molecules

The reactivity of mass-selected V4O10+ cluster ions toward hydrocarbon molecules including CH4, C2H4, and C2H6 was explored in the references case by case. Herein, further systematic studies on the reactions of V4O10+ with simple inorganic and organic molecules (H2, CO, CH4, C2H2, C2H4, and C2H6) are presented. The vanadium oxide cluster ions are prepared by laser ablation and the V4O10+ clusters are selected by a quadrupole mass filter and interacted with the simple molecules in a hexapole reaction cell. The reactant and product ions are detected by a reflectron time-of-flight mass spectrometer. Hydrogen and oxygen atom transfer reactions are observed. Density functional theory calculations are carried out for the reaction mechanism of V4O10++H2. The oxygen atom transfer (OAT) channel V4O10++H2→V4O9++H2O is much more exothermic than the hydrogen atom transfer (HAT) channel V4O10++H2→V4O10H++H whereas the former is less favorable than the later in terms of the reaction kinetics. The computational result is in good agreement with the experiment that the HAT (H2 splitting) rather than the OAT (water formation) is observed for V4O10++H2.

Research on the Rheological Property of Low-Rank Bitumite Coking Wastewater Slurry

Coking wastewater's components are complex, leading to treatment difficulties. Preparing the wastewater to slurries with low-rank bitumite can not only transform the high pollution components to simple and easy-treated inorganic molecules, but also utilize the heat it creates, and at the meanwhile expand the low-rank bitumite's application scope. Three coking wastewater samples of different treating depth, from a coking plant in Tangshan, were prepared slurries with a low-rank bitumite from a mine in Shanxi, and the slurries' rheological and temperature-depended properties were also tested. The results indicated that: preparing slurries with the feed of clean-room can optimize the flow-ability of which is with clean water; the viscosities reduce when heating the slurries, until the temperature increase over a unique value; the change pattern of the viscosity is depended on the properties of the interstitial water, water film and dispersant molecules by heating the slurries.

Anion inhibition studies of an α-carbonic anhydrase from the living fossil Astrosclera willeyana

An α-carbonic anhydrase (CA, EC 4.2.1.1) isolated from the living fossil sponge Astrosclera willeyana, Astrosclerin, was investigated for its inhibition profile with simple inorganic anions, complex anions and other small molecules known to interact with these zinc enzymes. Astrosclerin is a catalytically highly efficient enzyme, and is inhibited in the low micromolar range by sulfamide, sulfamic acid, phenylboronic acid and phenylarsonic acid, and in the submillimolar range by a variety of anions including fluoride, chloride, cyanate, thiocyanate, cyanide, hydrogen sulfide, bisulfate, stannate, perosmate, divanadate, perrhenate, perruthenate, selenocyanide, trithiocarbonate, diethyldithiocarbamate and iminodisulfonate. Less efficient Astrosclerin inhibitors were sulfate, bromide, iodide, azide, bicarbonate, carbonate, tetraborate and perchlorate (K(I)s of 5.11-30.6mM) whereas tetrafluoroborate was not at all inhibitory. Because Astrosclerin is involved in calcification processes in vivo, its anion inhibition profile may be important for future studies designed to shed light on the physiologic functions of α-CAs in marine organisms.