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Of the group 9 elements, only cobalt has a biological role. It is a key constituent of cobalamin , also known as vitamin B 12 , the primary biological reservoir of cobalt as an ultratrace element . [ 21 ] [ 22 ] Bacteria in the stomachs of ruminant animals convert cobalt salts into vitamin B 12 , a compound which can only be produced by ...
In chemistry, the valence (US spelling) or valency (British spelling) of an atom is a measure of its combining capacity with other atoms when it forms chemical compounds or molecules. Valence is generally understood to be the number of chemical bonds that each atom of a given chemical element typically forms.
A mnemonic is a memory aid used to improve long-term memory and make the process of consolidation easier. Many chemistry aspects, rules, names of compounds, sequences of elements, their reactivity, etc., can be easily and efficiently memorized with the help of mnemonics.
A chemical bond is an attraction between atoms. This attraction may be seen as the result of different behaviors of the outermost or valence electrons of atoms. These behaviors merge into each other seamlessly in various circumstances, so that there is no clear line to be drawn between them.
The first compound of this class was introduced 1975 with Cyclomusk, though similar structures were noted earlier in citronellyl oxalate and Rosamusk. [7] Alicyclic musks are dramatically different in structure than previous musks (aromatic, polycyclic, macrocyclic) in that they are modified alkyl esters. [ 8 ]
The side chains are: an ethyl- at carbon 4, an ethyl- at carbon 8, and a butyl- at carbon 12. Note: the −O−CH 3 at carbon atom 15 is not a side chain, but it is a methoxy functional group. There are two ethyl- groups. They are combined to create, 4,8-diethyl. The side chains are grouped like this: 12-butyl-4,8-diethyl.
The concept of PINs is defined in the introductory chapter and chapter 5 of the "Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013" (freely accessible), [4] which replace two former publications: the "Nomenclature of Organic Chemistry", 1979 (the Blue Book) and "A Guide to IUPAC Nomenclature of Organic Compounds ...
• the purple manganese oxyanion MnO − 4 from KMnO 4 This table lists the ionic species that are most likely to be present, depending on pH, in aqueous solutions of binary salts of metal ions. The existence must be inferred on the basis of indirect evidence provided by modelling with experimental data or by analogy with structures obtained ...