The case of carbonic acid This means that

The case of carbonic acid This means that carbonic acid is stronger than acetic acid!! However, the conventionally given p. Ka 1(apparent) value refers to the sum of CO 2 and H 2 CO 3:

Angew. Chem. Int. Ed. 2000, 39, 892 -894 Synthesis and isolation:

Buffer equation or Henderson-Hasselbalch Equation Lawrence Joseph Henderson Karl Albert Hasselbalch (June 3, 1978, Lynn, Massachusetts, USA – February 10, 1942 Boston, USA) Henderson studied medicine at Harvard and was Professor of Biological Chemistry at Harvard University, Cambridge, Massachusetts, from 1904 to 1942 [i]. Henderson published on the physiological role of buffers [ii-vii] and the relation of medicine to fundamental science. Because he and also Hasselbalch made use of the law of mass action to calculate the p. H of solutions containing corresponding acid-base pairs, the buffer equation is frequently (esp. in biological sciences) referred to as Henderson-Hasselbalch equation. (November 1, 1874, Aastrup, Denmark – September 19, 1962) Hasselbalch studied medicine and physiology, and received his Dr. med. in 1899 for a work on respiration. In 1903/04 he made a study tour to Berlin and Leipzig [i, ii]. Hasselbalch used the law of mass action for carbonic acid as proposed by Henderson to calculate the p. H of blood from the carbon dioxide, bicarbonate status [iii, iv]. Hence it happened that the buffer equation is frequently (esp. in the biological sciences) referred to as Henderson-Hasselbalch equation. Refs. : [i] Salié H (ed) (1973) JC Poggendorff Biographisch-literarisches Handwörterbuch der exakten Naturwissenschaften, vol VIIb. Akademie-Verlag Berlin; [ii] Henderson LJ (1908) Am J Physiol 21: 173; [iii] Henderson LJ, Spiro E (1908) Biochem Z 15: 105; [iv] Henderson LJ (1908) J Amer Chem Soc 30: 954; [v] Henderson LJ, Black OF (1908) Amer J Physiol 21: 420; [vi] Henderson LJ (1909) Ergebn Physiol 8: 254; [vii] Henderson LJ (1910) Biochem Z 24: 40; [vii] Henderson LJ (1909) Ergebn Physiol 8: 254 Refs. : [i] (1936) Dansk Biografisk Leksikon, vol 9. JH Schultz, København; [ii] (1994) Scandinavian Biographical Index. KG Saur, London; [iii] Hasselbalch KA (1916) Biochem Z 78: 112; [iv] Warburg EJ(1922) Biochem J 16153

Metal aqua ions are Brønsted acids [Me(H 2 O)n]m+ + H 2 O First acidity constant: [Me(H 2 O)n-1(OH)](m-1)+ + H 3 O+

(i. e. , ~ ion potential) The polarization of the O-H bond by the metal ion

m-th ionisation potential K. -H. Tytko: Chemie in unserer Zeit 13 (1979) 187

Examples: Charge of the metal ion Mn. O 4 Cr. O 42 -, Cr 2 O 72 - Fe 3+, Al 3+ Fe 2+, Ca 2+ K+, Na+ K. -H. Tytko: Chemie in unserer Zeit 13 (1979) 187

[Me(H 2 O)n]m+ + H 2 O [Fe(H 2 O)6]3+ [Me(H 2 O)n-1(OH)](m-1)+ + H 3 O+ p. Ka 1 = 2. 2 Acetic acid [Al(H 2 O)6]3+ p. Ka 1 = 4. 9 [Fe(H 2 O)6]2+ p. Ka 1 = 9. 5 [Zn(H 2 O)6]2+ p. Ka 1 = 9. 8 p. Ka 1 = 4. 75

The first protolysis reaction: [Me(H 2 O)n]m+ + H 2 O [Me(H 2 O)n-1(OH)](m-1)+ + H 3 O+ The second protolysis reaction: [Me(H 2 O)n-1(OH)](m-1)+ + H 2 O [Me(H 2 O)n-2(OH)2](m-2)+ + H 3 O+ The third protolysis reaction: [Me(H 2 O)n-2(OH)2](m-2)+ + H 2 O [Me(H 2 O)n-3(OH)3](m-3)+ + H 3 O+ … and so on …

Protolysis reactions are followed by condensation reactions [Me(H 2 O)n-1(OH)](m-1)+ + [Me(H 2 O)n-1(OH)](m-1)+ [Me(H 2 O)n-1 -O-M(H 2 O)n-1]2(m-1)+ + H 2 O Dimers, trimers, oligomers, polymers … solid precipitates

K. -H. Tytko: Chemie in unserer Zeit 13 (1979) 187

K. -H. Tytko: Chemie in unserer Zeit 13 (1979) 187

„Hydrolysis of Inorganic Iron(III) Salts“ C. M. Flynn, Jr. Chem. Rev. 84 (1984) 31 -41

The iron oxide story, or why the soils are brown Atmosphere 4[Fe(H 2 O)6]2+ + O 2 + 4 H+ 4[Fe(H 2 O)6]3+ + 2 H 2 O Corrosion of minerals on the surface Soil [Fe(H 2 O)6]2+ in groundwater

The iron oxide story, or why the soils are brown Iron oxides [Fe(H 2 O)6]3+ + H 2 O Hydroxocomplexes Iron oxide hydrates (Goethite, limonite, …) [Fe(H 2 O)6]2+ in groundwater

Ruda łąnkowa (darniowa, błotna) nem: Raseneisenerz Bog iron ore (morass ore) : Layers of Goethite (or limonite) around a sandstone cor

l Goethite nodules (buły) formed on the bottom of lake Schwielowsee, near Potsdam, Germ The diameters range from 1 to 6 mm.

start of sediment records overall O 2 gram 58% in Fe 2 O 3 gigantic redox titration of Fe 2+, S 2 -, Mn 2+, etc. with O 2 83% in SO 42 O 2 in oceans and atmosphere years before present Oxygen produced by photosynthesis. C = cyanobacteria, E = eobionts, EK = eukaryotes, R = red beds

Banded Iron Formations When the oceans first formed, the waters must have dissolved enormous quantities of reducing iron ions, such as Fe 2+. These ferrous ions were the consequences of millions of years of rock weathering in an anaerobic (oxygen-free) environment. The first oxygen produced in the oceans by the early prokaryotic cells would have quickly been taken up in oxidizing reactions with dissolved iron. This oceanic oxidization reaction produces Ferric oxide Fe 2 O 3 that would have deposited in ocean floor sediments. The earliest evidence of this process dates back to the Banded Iron Formations, which reach a peak occurrence in metamorphosed sedimentary rock at least 3. 5 billion years old. Most of the major economic deposits of iron ore are from Banded Iron formations. These formations, were created as sediments in ancient oceans and are found in rocks in the range 2 - 3. 5 billion years old. Very few banded iron formations have been found with more recent dates, suggesting that the continued production of oxygen had finally exhausted the capability of the dissolved iron ions reservoir. At this point another process started to take up the available oxygen. Red Beds Once the ocean reservoir had been exhausted, the newly created oxygen found another large reservoir - reduced minerals available on the barren land. Oxidization of reduced minerals, such as pyrite Fe. S 2 , exposed on land would transfer oxidized substances to rivers and out to the oceans via river flow. Deposits of Fe 2 O 3 that are found in alternating layers with other sediments of land origin are known as Red Beds, and are found to date from 2. 0 billion years ago. The earliest occurrence of red beds is roughly simultaneous with the disappearance of the banded iron formation, further evidence that the oceans were cleared of reduced metals before O 2 began to diffuse into the atmosphere.

Steep coast on Rügen island build up from chalk around 70 million years ago as sea sediment (on a grey December day in 2004)

Pyrite (Fe. S 2) nodule (buła) from the chalk of Rügen island (Germany) and Goethite nodules formed by oxidation of such pyrite nodules

Goethite nodules formed by oxidation and leaching of pyrite nodules. The primary product is a very acidic solution of iron(III) sulfate. This salt dissolves and it is washed away. Only at the outside Goethite is formed by protolysis, condensation and aging.

Acid Mine Drainage Rio Tinto, Spain (Wikipedia)

Biogeochemistry Profile of a hydrothermal ore course with sulfidic ore paragenesis in the oxidation-cementation zone

Acidithiobacillus ferrooxidans: oxidizes Fe(II) and sulfur (and S-compounds)) Acidithiobacillus thiooxidans: oxidizes sulfur (and S-compounds)) -autotrophic, chemolithotrophic: Oxidation von Fe 2+, S 0, S 2 -, S 2 O 32 - zu Fe 3+, SO 42 -; Electron acceptor: O 2 C-source: CO 2 Source: http: //www. google. de/imgres? imgurl=http: //2009. igem. org/wiki/images/thumb/4/4 a/Tokyo_tech_Iron_bacteria. jpg/300 px. Tokyo_tech_Iron_bacteria. jpg&imgrefurl=http: //2009. igem. org/ Team: Tokyo_Tech/Ironoxidizing_bacteria&usg=__BHHdz. C 2 o. XQx. ZWcanm 8 TBt 0 r 3 Br 0=&h=225&w=300&sz=11&hl=de&start=0&zoom=1&tbnid=e. Kmb. Skl ar 8 k. Ec. M: &tbnh=147&tbnw=196&ei=n. TDCTqf. A 4 a. Pswavjv 3 z. Cw&prev=/search%3 Fq%3 Dacidithiobacillus%26 um%3 D 1%26 hl%3 Dde%26 sa%3 DN%26 biw%3 D 1280%26 bih%3 D 841%26 tbm%3 Disch&um=1&itbs=1&iact=hc&vpx=204&vpy=540&dur=406&hovh=180&hovw=240&tx=126&ty=209&sig=10299631 9110756286540&page=1&ndsp=21&ved=1 t: 429, r: 16, s: 0 http: //www. google. de/imgres? imgurl=http: //www. amrita. ac. in/bioprojects/Indus. Micro. Bio/microb%2 520_cultech/images_culturetech/Acidithiobacillus %2520 ferrooxidans. jpg&imgrefurl=http: // www. am rita. ac. in/bioprojects/Indus. Micro. Bio/microb%252 0_cultech/Mbocultech 32. php&usg=__m 4_Tk. IJPi op. Oa. XVu. Ii_xw. Dd. PNKU=&h=223&w=570&sz=37 &hl=de&start=0&zoom=1&tbnid=Krfr. SLf. XIIBXq. M : &tbnh=90&tbnw=231&ei=n. TDCTqf. A 4 a. Pswavjv 3 z. Cw&prev=/search%3 Fq%3 Dacidit hiobacillus%26 um%3 D 1%26 hl%3 Dde%26 sa%3 DN%26 biw%3 D 1280%26 bih%3 D 841%26 tbm%3 Disch&um=1&itbs=1&iact=rc&dur=188&sig=1029 96319110756286540&page=1&ndsp=21&ved=1 t : 429, r: 1, s: 0&tx=53&ty=48

Naica cave, Mexico: 50 °C, 90% relative humidity; length of gypsum crystals up to 15 m; formed over about 500 000 years. Produced by Acidithiobacillus ferrooxidans!!

The biochemical relevance of the acidity of metal-aqua ions Rate constant of CO 2 + H 2 O → H 2 CO 3 : 0. 039 s− 1 Rate constant of H 2 CO 3 → CO 2 + H 2 O : 23 s− 1 Rate constants of the carbonic anhydrase-catalyzed reactions: CO 2 + H 2 O → H 2 CO 3 : 1. 000 s− 1 H 2 CO 3 → CO 2 + H 2 O : 400. 000 s− 1

Carbonic anhydrase The significance of the acidity of metal-aqua complexes for biochemistry, i. e. , for human life