Basic Copper Chloride Research Articles

Identification of Different Copper Green Pigments in Renaissance Paintings by Cluster-TOF-SIMS Imaging Analysis

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) imaging using cluster primary ion beams is used for the identification of a green painting layer on the scene The Angels Concert from the Issenheim Altarpiece (painted in 1516) from a German Renaissance painter, Matthias Grünewald. Copper carboxylate clusters inside a basic copper chloride (atacamite) layer have been identified and located in the copper green layer. The mechanisms of transformation of atacamite into copper carboxylates may be initiated by an aging of the paint layers. The combination of the high mass resolution of the technique together with a micrometer spatial resolution and the possibility to simultaneously identify both minerals and organics, has proven to be the method of choice for the study of the stratigraphy of a paint cross-section.

Mid-IR and Raman Spectral Properties of Clinoatacamite-Structure Basic Copper Chlorides

Basic copper chloride Cu2(OH)3Cl and Cu2(OD)3Cl polycrystalline sample were successfully synthesized in the same single phase of clinoatacamite-structure, and the latter’s mid-infrared absorption spectra (4000-400cm–1) and Raman spectra (4000-95cm–1) were first, to the best of our knowledge, measured respectively by FTIR spectroscopy and Micro-Raman spectroscopy to study the corresponding relationship between their spectral properties and crystal structure. Through the comparative analysis of the four spectra we definitely assign or tentatively suggest the vibration modes of OH/D groups in the trimeric hydrogen bond environment, (H/DO)–Cu–(OH/D), Cl–Cu–Cl. These results can be propitious to their low temperature spectral properties which must help to understand the underlying physics of their exotic geometric frustration phenomenon.

Tolerance for excess basic zinc chloride and basic copper chloride in chicks

1. Four chick experiments were conducted to determine toxicity estimates for basic zinc chloride (BZC) and basic copper chloride (BCC), now being used as sources for these minerals. 2. In experiment 1, New Hampshire × Columbian crossbred chicks were fed 0, 500, 1000, 1500, 3000 and 5000 mg Zn/kg from BZC (Zn5Cl2(OH)8). Broken-line regression analysis showed that the minimal toxic break points for chick weight gain and gain:food were 1720 and 2115 mg Zn/kg, respectively. 3. Crossbred chicks were fed 0, 150, 250, 500, 750 and 1000 mg Cu/kg from BCC (Cu2(OH)3C) in experiment 2. Regression analysis indicated that the minimal toxic break points for chick weight gain and gain:food were 642 and 781 mg Cu/kg, respectively. 4. In experiment 3, commercial broiler chicks were fed 0, 1500, 2000 and 2500 mg supplemental Zn/kg from BZC or 0, 500, 650 and 800 mg supplemental Cu/kg from BCC. Broiler chicks fed those high inclusion rates of Zn did not show reduced weight gain in comparison to chicks fed no supplemental Zn. All high concentrations of supplemental Cu depressed chick weight gain in comparison to control chicks. 5. Experiment 4 involved two separate 4 × 2 factorial designs with supplemental Zn (0, 2500, 3500 and 4500 mg/kg) or Cu (0, 500, 750 and 1000 mg/kg) and two breeds of chicks (crossbred and commercial). Significant interactions for weight gain, food intake, gain:food and liver Cu suggested that the crossbred and commercial chicks responded differently to high concentrations of supplementary dietary Cu.

Raman and infrared spectroscopic study of the basic copper chloride minerals - implications for the study of the copper and brass corrosion and "bronze disease"

The vibrational spectra of both synthetic and natural atacamite and clinoatacamite are compared with natural paratacamite, have been obtained at 298 using a combination of FTIR and Raman microscopy. The vibrational spectra of the minerals are different, in line with differences in crystal structure and composition. The vibrational spectra of paratacamite are different from that of both atacamite and clinoatacamite. Paratacamite is not polymorphic with atacamite but rather is a separate phase. Some similarity in the Raman spectra of the polymorphs exists, particularly in the OH stretching region, but characteristic differences in the OH deformation regions are observed. These differences may be used to characterize the minerals. Differences are also observed in the chloride stretching and deformation regions. The implication from the study of these minerals is that copper, brass and bronze objects of archaeological, antiquarian and medieval significance can be studied by the use of Raman spectroscopy. Indeed the restoration of these types of articles can be aided by the application of Raman spectroscopy to the study of the degradation products from paintings of antiquity.

Raman spectroscopy of the basic copper chloride minerals atacamite and paratacamite: implications for the study of copper, brass and bronze objects of archaeological significance

AbstractRaman spectra of the basic copper chloride minerals atacamite and paratacamite were obtained at 298 and 77 K using a Raman microprobe in combination with a thermal stage. Four distinct regions involved with hydroxyl stretching, hydroxyl deformation, CuO stretching and CuCl stretching and bending were identified. The implication from the study is that Raman spectroscopy can be a useful tool for identifying corrosion products of copper, brass and bronze objects of archaeological or antiquarian significance. In addition, the technique may be a useful aid in the restoration degraded pigment products from old paintings. Copyright © 2002 John Wiley & Sons, Ltd.

A Note on the Efficacy of Ethylenediaminetetraacetic Acid Disodium Salt as a Stripping Agent for Corrosion Products of Copper

The efficacy of ethylenediaminetetra-acetic acid disodium salt (EDTANa2) as a stripping agent for the removal of corrosion products of copper have been studied by simulation experiment. Six corrosion products of copper—malachite. nantokite, basic copper (II) chloride, parafacamife, atacamite and brochantite—were synthesized. The interaction between the solid metal, corrosion products and EDTANa2 was evalated by estimating the amount of copper dissolved in the EDTANa2 and calculating the rate of dissolution at various concentrations and time. As Cu-EDTANa2 water-soluble-complex, EDTANa2 is a good stripping agent for the remoral of corrosion products of copper, without affecting the surface of the metallic copper. The rate of dissolution of corrosion products in EDTANa2 depends on the properties and constituents of individual corrosion products and the concentration of EDTANa2. It is can eluded from these findings that the lIilOle process is controlled by forces of diffusion.

A corrosion inhibitor test for copper-based artifacts

A new quantitative corrosion testing procedure for copper and copper alloy corrosion inhibitors was developed, with the aim of calculating corrosion protection in percent for each inhibitor on trial. 2-aminopyrimidine, 2-amino-5-mercapto-1,3,4-thiadiazole, benzotriazole, 5,6-dimethylbenzimidazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptopyrimidine and 2-mercaptobenzothiazole were tested for their effectiveness in preventing the conversion of nantokite (copper (I) chloride, CuCl) into paratacamite (basic copper (II) chloride, CuCl2·3Cu(OH)2) which causes major damage in archaeological copper artifacts.

Green degradation products of azurite in wall paintings: identification and conservation treatment

After the restoration of the fourteenth- to fifteenth-century wall painting of San Antonio Abate in the church of San Pietro at Quaracchi near Florence, using the well-known treatment involving application of ammonium carbonate followed by barium hydroxide, a small region of the green degradation products of azurite changed colour to a dark blue. After two years, this blue had again changed colour, showing that the conservation procedure could cause chemical alterations, and that it had produced an unstable material. This study investigated the chemistry of these phenomena, in order to determine whether a conservation procedure based on the application of ammonium carbonate and barium hydroxide is suitable and appropriate in the presence of certain green degradation products of azurite. Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD) showed that the main green degradation product was not malachite but paratacamite, a basic copper chloride which forms when there is a source of chloride ions in proximity to the painting. The blue colour that appeared after the treatment was identified as copper hydroxide. Experiments on plaster samples painted with paratacamite showed that this compound is easily soluble in a solution of ammonium carbonate, while treatment with barium hydroxide produced a blue copper hydroxide which is unstable and can form either black copper oxide or, in the presence of chloride ions, a mixture of atacamite and paratacamite. This paper also showed that, when basic copper chlorides are present as green degradation products of azurite, the conservation procedure based on ammonium carbonate and barium hydroxide caused cyclic reactions resulting in the dissolution of paratacamite from the surface, formation of copper hydroxide and degradation of the blue copper hydroxide into either green paratacamite if the chloride ion source is not removed, or to black copper oxide. Great care must, therefore, be taken by conservators and restorers when these green degradation products of azurite are present in a wall painting.

Atmospheric corrosion of copper at Heron Island

Atmospheric corrosion tests have been conducted at Heron Island, Queensland, a low SO 2 marine environment. The corrosion rates for copper followed the linear bi-logarithmic law. X-ray diffraction identified atacamite (basic copper chloride) and cuprite (cuprous oxide) as the predominant corrosion products. Biogenic and anthropogenic sources of pollution did not have a measurable influence.

Magnetic properties of copper chloride hydroxide hydrate Cu 3Cl 4(OH) 2·2H 2O

A weak ferromagnetic signal at T N = 17.5 K has been observed in the FC branch of dc magnetic susceptibility of the basic copper chloride Cu 3Cl 4(OH) 2·2H 2O. Magnetization measurements at 10 K showed a hysteresis loop. The saturation moment was 0.012 μ B Cu . The ferromagnetic behavior was produced by only a small fraction of the Cu moments.

The mineralization of fibres in burial environments

Abstract The mineralization of cellulosic and proteinaceous fibres has been simulated using oxygenated aqueous solutions. In addition to chemical analysis of the fibres and the aqueous media, the reactions of the fibres were studied by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) microscopy and reflectance UV spectroscopic techniques. Both positive and negative casting mechanisms were observed. The mechanism peculiar to a given solution depends on kinetic factors relating to the mineral product formation; in particular the relative mineralization rates of the basic copper(II) chloride trimorphs are considered. Mineralization of fibres occurs within days of deposition in the burial environment and acts to preserve the fibre morphology. These experiments rationalize both the occurrence and the comparative rarity of mineralized organic fibres from archaeological deposits. Traces of the organic component have been shown to survive long-term burial and, in appropriate circumstances, pe...

Electron crystallography of inorganic compounds. Direct determination of the basic copper chloride structure CuCl2·3Cu(OH)2

Experimental electron diffraction intensity data from basic copper chloride CuCl2·3Cu(OH)2 in its metastable form have been used for a direct structure analysis based on the evaluation of three and four phase structure invariants. The resultant electrostatic potential maps clearly show the correct atomic positions which correspond to those determined earlier by Voronova and Vainshtein (1958) from their interpretation of Patterson maps, and also to the X-ray analysis of the isostructural CuBr2·3Cu(OH)2 carried out by Aebi in 1948.

A Morphological Study of Pitting Corrosion of Copper in Soft Tap Water

Abstract A morphological study was carried out on the pitting corrosion of copper in soft tap water at room temperature. Pitting corrosion was initiated through localized breakdown of a relatively thin protective cuprous oxide film. This film increased in thickness and became a scale that separated from the metal surface by cuprous oxide crystals. The oxide crystals ruptured the scale and extruded from it forming mounds at sites that corresponded to grain boundaries. The initiation of pitting attack was observed along the grain boundaries, and the pits developed into hemispherical shapes. After the pits were already established, basic copper sulfate corrosion products were formed on top of the scale through a precipitation reaction that involved basic copper chloride crystals grown underneath the scale. A new mechanism is proposed that can explain pitting corrosion of copper in soft and hard waters. The presence of chloride ions is a prerequisite in the breakdown of the film and the initiation of pitting ...

The oxidative coupling polymerization of 2.6‐dimethylphenol with basic copper(II) chloride‐pyridine complex

AbstractThe results of the investigation on the oxidative coupling polymerization reaction of 2.6‐dimethylphenol in the presence of copper(II) chloride‐pyridine‐KOH complex (basic copper(II) complex) are reported. The yield of poly(2.6‐dimethyl‐4.4′‐phenylene oxide) which is the CO coupling product closely depends upon the copper(II) chloride concentration, the ratio of pyridine/copper(II) chloride, and the ratio of KOH/copper(II) chloride. However, the yield of 3.3′.5.5′‐tetramethyl‐4.4′‐diphenoquinone, the CC coupling product, scarcely changes with these reaction conditions.The rate of polymerization of 2.6‐dimethylphenol under oxygen was much larger than that determined in an air atmosphere.The basic copper(II) chloride complex catalyst showed the unusual property that the electron spin resonance‐detectable copper(II) ion in the basic copper(II) chloride complex was only 35 ± 5% using pure copper(II) chloride‐pyridine complex not containing KOH as a standard.It has been found by means of ESR measurements that the basic copper(II) complex had the function of an one‐electron transfer reagent.

Atmospheric corrosion of copper and some copper alloys

Two-year atmospheric corrosion tests in an urban environment were conducted on specimens of copper, Muntz metal, and copper-zinc-aluminum alloys. X-ray diffraction and X-ray spectrographic studies were made of the films on the top surface and underside of the exposure coupons which were exposed facing south but inclined at a 45° angle to the vertical. Differences between the two surfaces are attributed to the leaching action of rain as well as the possible effect of direct sunlight. The corrosion products of copper were found to consist predominantly of Cu2O, but also included a substance of undetermined composition, copper chloride and basic copper chloride. The zinc-containing alloys formed similar products, along with zinc sulphates, and showed considerable dezincification. A preoxidation treatment improved the tarnished appearance of the ternary alloy. Résumé Des essais de corrosion atmosphérique en milieu urbain ont été exécutés sur du cuivre, du métal Muntz et des alliages Cu-Zn-Al. Les échantillons étaient placés à un angle de 45°, face au sud et des mesures de diffraction aux rayons-X et de spectrographie X ont été faites sur chacune des faces. Les differences entre les deux faces d'un même échantillon peuvent étre attribuables à la pluie et peut-être aussi au solell. Les produits de corrosion du cuivre sont surtout formés de Cu2O et également du chlorure de cuivre, du chlorure basique de cuivre et un composé non identifié sur les alliages contenant du zinc des produits semblables se sont formés avec aussi des sulfures de zinc; on y notait aussi une dézincification. Dne oxydation avant les essais améliorait l'apparence finale des alliages ternaires.

Replacement of calcite by atacamite in copper chloride solutions

Replacement of calcite by basic copper chloride has been studied as a function of time, temperature, and concentration in flowing solutions. The replacement does not follow the laws of chemical equivalence; instead, the control is a rough type of catalysis on the calcite surface. The mechanism gives great promise of producing volume for volume replacements.

Societies and Academies

LONDON Institute of Metals (Silver Jubilee Autumn Meeting at Birmingham), September 18–21. O. F. HUDSON: Wear in the polishing of plated and other surfaces. The following materials, using magnesia on wet parchment as the polishing medium, were examined: pure platinum, pure palladium, platinum plating on brass, palladium plating (?soft?,?hard?, and burnished) on brass, nickel plating (?soft? and?hard?) on brass, silver plating, and brass (60: 40). Considered as loss of thickness, the rate of wear of the palladium-plated specimens was found to be greater than that of the platinum-plated specimens, but considered as loss of weight, the wear of the palladium coatings was slightly less than that of the platinum coatings? whilst the precious metal coatings generally were more resistant than the same metals in massive form. W. HUME-ROTHERY: A graphical method for converting the weight percentage compositions of ternary systems into atomic or molecular percentages. The method is suitable for use where 60° ruled triangular paper is available. It permits the direct transference of a triangular diagram drawn on the weight percentage scale to one in atomic percentages, and the accuracy obtained is of the order 0?l-0?5 per cent, according to the precision of the instruments and of the ruled paper. BRINLEY JONES: Preparation of lead and lead alloys for microscopic examination. Time devoted to preliminary polishing is restricted, the true structure of the metal being revealed by chemical solution of surface layers. After the removal of recrystallised layers, sections may finally be prepared for highpower examination by a treatment of alternate polishing and etching, the final polishing being vigorous. D. G. JONES, L. B. PFEIL and W. T. GRIFFITHS: Precipitation-hardening nickel-copper alloys containing aluminium. The properties of nickel-copper-aluminium alloys with nickel contents from 10 to 45 per cent and aluminium contents up to 4 per cent have been investigated. The relationships between composition and capacity for hardening by heat-treatment have been studied by means of hardness tests on the heat-treated specimens. A study has also been made of the most suitable heatreatments to produce the soft condition, and the stability at elevated temperatures of a selection of the alloys in the precipitation-hardened condition. H. O?NEILL, G. S. FARNHAM and J. F. B. JACKSON: An investigation of the heat-treatment of?standard silver?. The precipitation-hardening of quenched?standard silver? (7.25 per cent copper) has been investigated by Meyer hardness analysis. Precision X-ray spectrograms obtained with Cu-radiation from thick disc specimens of the heat-treated alloy indicate that surface preparation may considerably affect the lattice parameter results. Polishing should be avoided in this work, and etching may have bad effects. Quenched?standard silver? when reheated for 30 minutes in the 300° C. region is in a sensitive condition, and appears to precipitate completely when deformed. If precautions are taken, the lattice parameters indicate a normal progressive precipitation of copper constituent as the quenched alloy is reheated at increasing temperatures. D. STOCKDALE: The constitution of the aluminium-rich aluminium-copper alloys above 400° C. A part of the work of Dix and Richardson on the solubility of copper in aluminium has been repeated and their results have been closely confirmed. A considerable range of solid solutions has been found near the composition CuAl2, but no evidence for the existence of the compound CuAl2 has been obtained. W. H. J. VERNON: Green patina on copper: examples from Elan Valley, Wales, and Dundalk, Ireland. The patina from a copper structure in mid-Wales contained 20-75 per cent basic copper chloride, as compared with 8.15 per cent in the patina from a copper spire at Dundalk, on the east coast of Ireland (approximate ratio 2.5: 1)? this result is attributed to the influence of prevailing winds. Basic copper sulphate constituted the bulk of the deposit in each case, relationship of formula with period of exposure confirming the conclusions of previous work.