One heritage corrosion product less: basic sodium copper carbonate

Eggert, Gerhard; Fischer, Andrea; Dinnebiér, Robert E.

doi:10.1186/s40494-016-0092-3

Cited by 5 publications

(4 citation statements)

References 11 publications

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“…Despite being a resourceful collector of compounds, SCOTT missed (and from hindsight, rightfully) an arcane basic sodium copper(II) carbonate, Na 3 [Cu 2 (CO 3 ) 3 (OH)]•4H 2 O (ICDD 00-28-1084), which was listed-without any further information-as a corrosion product identified through powder diffraction ( [32],: 167) on a cover glass of a daguerréotype (photosensitised silver layer on copper). Through synthesis experiments and the evaluation of XRPD peak lists and FTIR spectra, we could prove [33] that the postulated compound [34] is nothing other than chalconatronite; consequently, ICDD have now deleted this chart. Therefore, the listing by Barger and White [32] can now be taken as further proof of chalconatronite on another group of combined glass/metal objects.…”

Section: Rare Copper Carbonatesmentioning

confidence: 99%

“…In contrast to modern diffractograms, the angle measurements were not precise and stopped at 2Θ = 51 • , and the intensities were only estimated visually. To analyse complex mixtures, it should now be replaced by high quality data derived from the crystal structure, e.g., ICDD 01-71-1490 ( [33], Table I), covering a larger range with truly quantitative values for intensities. Such a re-evaluation could possibly solve the riddle of chalconatronite, which has been reported as a minor component together with quartz, atacamite, and cuprite in the outer concretion of the Riace Warrior A, recovered from the sea off Calabria (SCOTT 120, 328; [35]).…”

Section: Rare Copper Carbonatesmentioning

confidence: 99%

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‘Copper and Bronze in Art’ and the Search for Rare Corrosion Products

Eggert

2023

Heritage

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The information taken from David A. Scott’s book “Copper and Bronze in Art” was crucial for this research on copper corrosion products in Stuttgart. The examples discussed are: (1) the nature and variability of ‘Black Spots’ (or ‘Brown Fuzzies’), mainly copper sulfides, resulting from the action of sulfurous gases on copper containing materials at different relative humidities; (2) cupric hydroxide occurring during maritime corrosion or by cleaning, patination, and pigment synthesis (Bremen blue) when alkaline solutions are used; (3) the wondrous phenomenon of curly malachite, which does not imply any human involvement; (4) chalconatronite formed by the contact of metal to alkaline surface films on soda glass, providing sodium and carbonate ions; (5) the formation of copper formates in contact with glass by the action of electrolytes from the glass hydrolysis and the pollutant formaldehyde reacting to the formate; (6) syntheses and crystal structure determination by powder X-ray diffraction (no single crystals needed) of various basic copper acetates (‘verdigris’) with the aim to better differentiate between historic production methods.

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Section: Rare Copper Carbonatesmentioning

confidence: 99%

Section: Rare Copper Carbonatesmentioning

confidence: 99%

‘Copper and Bronze in Art’ and the Search for Rare Corrosion Products

Eggert

2023

Heritage

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“…In the latter case, the corrosion product was originally identified as Na 3 [Cu 2 (CO 3 ) 3 (OH)]•4H 2 O, ICDD 00-28-1084 [27] based on the original publication of this compound [28]. Evaluation of their XRD peak list and their FTIR spectra and own synthesis experiments proved that the compound was nothing other than chalconatronite [29]. Consequently, ICDD deleted the chart.…”

Section: Kpb2(co3)2(oh) ②mentioning

confidence: 99%

Curious Corrosion Compounds Caused by Contact: A Review of Glass-Induced Metal Corrosion on Museum Exhibits (GIMME)

Eggert¹,

Fischer²

2022

CMD

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Many heritage objects consist of glass in contact with metals. By ion exchange with absorbed water, alkaline aqueous films are formed on the glass surface. They contain sodium and/or potassium, hydroxide, and carbonate (uptake of carbon dioxide) ions. These electrolytes induce corrosion while in contact with metal. Surprisingly, this phenomenon has only been realised by research in Stuttgart in the last two decades. About 350 affected objects were detected in the meantime in a number of heritage collections. Because of the special electrolytes, unusual corrosion products are often formed. The unknown structure and formula of three of them could be determined by modern X-ray powder diffraction data evaluation. One example is the basic potassium lead carbonate, KOH‧2PbCO3, detected on a pewter lid of a glass jug. The sodium analogon of already known structure was found in hollow glass balls mirrored on the inside with molten lead. Chalconatronite, Na2[Cu(CO3)2]‧3H2O, is known as a corrosion product of copper alloys in contact with soda solutions (here: from glass degradation). Exposed to acetic acid emissions (e.g., from wood), it transforms to a sodium copper acetate carbonate of hitherto undetermined structure. The ubiquitous pollutant formaldehyde reacts directly to formate in the alkaline medium provided by glass degradation. On copper alloys in contact with glass, formates are, therefore, frequent: Na4Cu4O(HCOO)8(OH)2‧4H2O in 50% of all cases and in 33% Cu2(HCOO)(OH)3. Zinc (from brass) forms Zn(HCOO)2‧2H2O and Zn4Cu3(Zn1−xCux)6(HCOO)8 (OH)18·6H2O. There are a number of other corrosion products, e.g., containing zinc and carboxylates awaiting further characterisation. Preventive conservation needs to slow down corrosion by dry storage (not lower than 35% rH). Pollutants need to be avoided by careful selection of materials for storage, display, and conservation.

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“…7: Corrosion on a nickel silver reflector (p-RFA: ca 60% Cu, 24% Zn, 13% Ni) of a miner's lamp in contact with glass: chalconatronite and a basic zinc copper formate (see below), photo: A. Schorpp, ABK Despite being a resourceful collector of compounds, SCOTT missed (and from hindsight, rightfully) an arcane basic sodium copper(II) carbonate: Na3[Cu2(CO3)3(OH)]•4H2O (ICDD 00-28-1084) was listedwithout any further information -as a corrosion product identified by powder diffraction (Barger and White 1991: 167) on a cover glass of a daguerréotype (photosensitised silver layer on copper). By synthesis experiments and evaluation of XRPD peak lists and FTIR spectra, we could prove (Eggert et al 2016) that the postulated compound (Sengupta and Nandi 1974) is nothing other than also chalconatronite; consequently, ICDD now deleted this chart. Therefore, the listing by Barger and White can now be taken as another proof for chalconatronite on another group of combined glass/metal objects.…”

Section: Rare Copper Carbonatesmentioning

confidence: 99%

'Copper and Bronze in Art' and the Search for Rare Corrosion Products

Eggert¹

2021

Preprint

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Information taken from David A. Scott’s book “Copper and Bronze in Art” was crucial for research on copper corrosion products in Stuttgart. Examples discussed are the nature and variability of ‘Black Spots’ (aka ‘Brown Fuzzies’); cupric hydroxide by cleaning, patination, and pigment synthesis; the wondrous phenomenon of curly malachite; chalconatronite formed by contact to soda glass; the formation of copper formates by glass-induced metal corrosion; and synthesis and X-ray diffraction of basic copper acetates (‘verdigris’).

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One heritage corrosion product less: basic sodium copper carbonate

Cited by 5 publications

References 11 publications

‘Copper and Bronze in Art’ and the Search for Rare Corrosion Products

‘Copper and Bronze in Art’ and the Search for Rare Corrosion Products

Curious Corrosion Compounds Caused by Contact: A Review of Glass-Induced Metal Corrosion on Museum Exhibits (GIMME)

'Copper and Bronze in Art' and the Search for Rare Corrosion Products

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