Group 9 element: Difference between revisions
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All known [[isotopes]] of meitnerium are radioactive with short half-lives. Only minute quantities have been synthesized in laboratories. It has not been isolated in pure form, and its physical and chemical properties have not been determined yet.{{Citation needed|date=March 2022}} |
All known [[isotopes]] of meitnerium are radioactive with short half-lives. Only minute quantities have been synthesized in laboratories. It has not been isolated in pure form, and its physical and chemical properties have not been determined yet.{{Citation needed|date=March 2022}} |
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==Biological role== |
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{{Main|Cobalt#Biological role}} |
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Of the group 9 elements, only cobalt has a biological role. It is a key constituent of [[Vitamin B12|cobalamin]], also known as vitamin B{{sub|12}}, the primary biological reservoir of cobalt as an [[ultratrace element]].<ref>{{cite book|first1=Kazuhiro|last1=Yamada|editor=Astrid Sigel |editor2=Helmut Sigel |editor3=Roland K. O. Sigel|title=Interrelations between Essential Metal Ions and Human Diseases|series=Metal Ions in Life Sciences|volume=13|date=2013|publisher=Springer|pages=295–320|chapter=Chapter 9. Cobalt: Its Role in Health and Disease|doi=10.1007/978-94-007-7500-8_9|pmid=24470095 |
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}}</ref><ref>{{cite book|last1=Cracan|first1=Valentin |last2=Banerjee|first2=Ruma |editor1-first=Lucia |editor1-last=Banci |series=Metal Ions in Life Sciences |volume=12|chapter= Chapter 10 Cobalt and Corrinoid Transport and Biochemistry|title=Metallomics and the Cell |date=2013 |pages=333–374 |publisher=Springer |isbn=978-94-007-5560-4|doi=10.1007/978-94-007-5561-1_10|pmid=23595677 }} electronic-book {{ISBN|978-94-007-5561-1}} {{issn|1559-0836}} electronic-{{issn|1868-0402}}. |
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</ref> [[Bacteria]] in the stomachs of [[ruminant]] animals convert cobalt salts into vitamin B{{sub|12}}, a compound which can only be produced by bacteria or [[archaea]]. A minimal presence of cobalt in soils therefore markedly improves the health of [[grazing]] animals, and an uptake of 0.20 mg/kg a day is recommended, because they have no other source of vitamin B{{sub|12}}.<ref>{{cite journal |last1 = Schwarz |first1 = F. J. |last2 = Kirchgessner |first2 = M. |last3 = Stangl |first3 = G. I. |title = Cobalt requirement of beef cattle – feed intake and growth at different levels of cobalt supply |journal = Journal of Animal Physiology and Animal Nutrition |volume = 83 |pages = 121–131 |date = 2000 |doi = 10.1046/j.1439-0396.2000.00258.x |issue = 3}}</ref> |
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Proteins based on cobalamin use [[corrin]] to hold the cobalt. Coenzyme B<sub>12</sub> features a reactive C-Co bond that participates in the reactions.<ref>{{cite book |author=Voet, Judith G. |author2=Voet, Donald |title=Biochemistry |publisher=J. Wiley & Sons |location=New York |date=1995 |page=[https://archive.org/details/biochemistry00voet_0/page/675 675] |isbn=0-471-58651-X |oclc=31819701 |url-access=registration |url=https://archive.org/details/biochemistry00voet_0/page/675 }}</ref> In humans, B<sub>12</sub> has two types of [[Alkane|alkyl]] [[ligand]]: [[Methyl group|methyl]] and adenosyl. [[Methylcobalamin|MeB<sub>12</sub>]] promotes methyl (−CH<sub>3</sub>) group transfers. The adenosyl version of B<sub>12</sub> catalyzes rearrangements in which a hydrogen atom is directly transferred between two adjacent atoms with concomitant exchange of the second substituent, X, which may be a carbon atom with substituents, an oxygen atom of an alcohol, or an amine. [[Methylmalonyl coenzyme A mutase]] (MUT) converts [[L-methylmalonyl-CoA|MMl-CoA]] to [[succinyl-CoA|Su-CoA]], an important step in the extraction of energy from proteins and fats.<ref>{{cite journal |last1 = Smith |first1 = David M. |last2 = Golding |first2 = Bernard T. |last3 = Radom |first3 = Leo |title = Understanding the Mechanism of B12-Dependent Methylmalonyl-CoA Mutase: Partial Proton Transfer in Action |journal = Journal of the American Chemical Society |volume = 121 |pages = 9388–9399 |date = 1999 |doi = 10.1021/ja991649a |issue = 40}}</ref> |
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==See also== |
==See also== |
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==References== |
==References== |
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{{Periodic table (navbox)}} |
{{Periodic table (navbox)}} |
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Revision as of 18:52, 12 October 2023
Template:Periodic table (group 9) Group 9, by modern IUPAC numbering,[1] is a group (column) of chemical elements in the periodic table. Members of Group 9 include cobalt (Co), rhodium (Rh), iridium (Ir) and meitnerium (Mt).[2][page needed] These are all transition metals in the d-block, considered to be some of the most rare of which.[3]
Like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior; however, rhodium deviates from the pattern.
"Group 9" is the modern standard designation for this group, adopted by the IUPAC in 1990.[2]
In the older group naming systems, this group was combined with group 8 (iron, ruthenium, osmium, and hassium) and group 10 (nickel, palladium, platinum, and darmstadtium) and called group "VIIIB" in the Chemical Abstracts Service (CAS) "U.S. system", or "VIII" in the old IUPAC (pre-1990) "European system" (and in Mendeleev's original table).
Chemistry
| Z | Element | No. of electrons per shell |
M.P. | B.P. | Year of Discovery |
Discoverer |
|---|---|---|---|---|---|---|
| 27 | cobalt | 2, 8, 15, 2 | 1768 K 1495 °C |
3200 K 2927 °C |
~1735 | Georg Brandt |
| 45 | rhodium | 2, 8, 18, 16, 1 | 2237 K 1964 °C |
3968 K 3695 °C |
1803 | W. H. Wollaston |
| 77 | iridium | 2, 8, 18, 32, 15, 2 | 2719 K 2446 °C |
4403 K 4130 °C |
1803 | S. Tennant |
| 109 | meitnerium | 2, 8, 18, 32, 32, 15, 2[*] | — | — | 1982 | P. Armbruster and G. Münzenberg |
[*] Predicted.
The first three elements are hard silvery-white metals:
- Cobalt is a metallic element that can be used to turn glass a deep blue color.
- Rhodium can be used in jewelry as a shiny metal.
- Iridium is mainly used as a hardening agent for platinum alloys.
All known isotopes of meitnerium are radioactive with short half-lives. Only minute quantities have been synthesized in laboratories. It has not been isolated in pure form, and its physical and chemical properties have not been determined yet.[citation needed]
Biological role
Of the group 9 elements, only cobalt has a biological role. It is a key constituent of cobalamin, also known as vitamin B12, the primary biological reservoir of cobalt as an ultratrace element.[4][5] Bacteria in the stomachs of ruminant animals convert cobalt salts into vitamin B12, a compound which can only be produced by bacteria or archaea. A minimal presence of cobalt in soils therefore markedly improves the health of grazing animals, and an uptake of 0.20 mg/kg a day is recommended, because they have no other source of vitamin B12.[6]
Proteins based on cobalamin use corrin to hold the cobalt. Coenzyme B12 features a reactive C-Co bond that participates in the reactions.[7] In humans, B12 has two types of alkyl ligand: methyl and adenosyl. MeB12 promotes methyl (−CH3) group transfers. The adenosyl version of B12 catalyzes rearrangements in which a hydrogen atom is directly transferred between two adjacent atoms with concomitant exchange of the second substituent, X, which may be a carbon atom with substituents, an oxygen atom of an alcohol, or an amine. Methylmalonyl coenzyme A mutase (MUT) converts MMl-CoA to Su-CoA, an important step in the extraction of energy from proteins and fats.[8]
See also
References
- ^ Fluck, E. (1988). "New Notations in the Periodic Table" (PDF). Pure Appl. Chem. 60 (3): 431–436. doi:10.1351/pac198860030431. S2CID 96704008. Retrieved 24 March 2012.
- ^ a b Leigh, G. J. Nomenclature of Inorganic Chemistry: Recommendations 1990. Blackwell Science, 1990. ISBN 0-632-02494-1.
- ^ "Group 9: Transition Metals". Chemistry LibreTexts. 2020-08-15. Retrieved 2022-03-24.
- ^ Yamada, Kazuhiro (2013). "Chapter 9. Cobalt: Its Role in Health and Disease". In Astrid Sigel; Helmut Sigel; Roland K. O. Sigel (eds.). Interrelations between Essential Metal Ions and Human Diseases. Metal Ions in Life Sciences. Vol. 13. Springer. pp. 295–320. doi:10.1007/978-94-007-7500-8_9. PMID 24470095.
- ^ Cracan, Valentin; Banerjee, Ruma (2013). "Chapter 10 Cobalt and Corrinoid Transport and Biochemistry". In Banci, Lucia (ed.). Metallomics and the Cell. Metal Ions in Life Sciences. Vol. 12. Springer. pp. 333–374. doi:10.1007/978-94-007-5561-1_10. ISBN 978-94-007-5560-4. PMID 23595677. electronic-book ISBN 978-94-007-5561-1 ISSN 1559-0836 electronic-ISSN 1868-0402.
- ^ Schwarz, F. J.; Kirchgessner, M.; Stangl, G. I. (2000). "Cobalt requirement of beef cattle – feed intake and growth at different levels of cobalt supply". Journal of Animal Physiology and Animal Nutrition. 83 (3): 121–131. doi:10.1046/j.1439-0396.2000.00258.x.
- ^ Voet, Judith G.; Voet, Donald (1995). Biochemistry. New York: J. Wiley & Sons. p. 675. ISBN 0-471-58651-X. OCLC 31819701.
- ^ Smith, David M.; Golding, Bernard T.; Radom, Leo (1999). "Understanding the Mechanism of B12-Dependent Methylmalonyl-CoA Mutase: Partial Proton Transfer in Action". Journal of the American Chemical Society. 121 (40): 9388–9399. doi:10.1021/ja991649a.
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