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Enantiotopic groups are identical and indistinguishable except in chiral environments. For instance, the CH 2 hydrogens in ethanol (CH 3 CH 2 OH) are normally enantiotopic, but can be made different (diastereotopic) if combined with a chiral center, for instance by conversion to an ester of a chiral carboxylic acid such as lactic acid, or if coordinated to a chiral metal center, or if ...
One example is [Ru(NH 3) 5 (SMeEt)] 2+. The complex cis-VOCl 2 (SMeEt) 2 exists as meso- and a pair of enantiomers. [7] In complexes of thioethers of the type S(CH 2 R) 2 (R ≠ H), the methylene protons are diastereotopic. Examination of the NMR spectra of such complexes reveal that they undergo inversion at sulfur, without dissociation of the ...
These are biblical figures unambiguously identified in contemporary sources according to scholarly consensus.Biblical figures that are identified in artifacts of questionable authenticity, for example the Jehoash Inscription and the bullae of Baruch ben Neriah, or who are mentioned in ancient but non-contemporary documents, such as David and Balaam, [n 1] are excluded from this list.
Symmetrical norbornanes and similarly rigid compounds (e.g. 7-oxabicyclo[2.2.1]heptane) also show complex signals for the ethylene fragments, made more complicated by additional splitting by the bridgehead protons. Reich gives several additional examples of magnetic inequivalence in acyclic and cyclic systems containing H 2 C-CH 2 fragments. [3]
In discussing the role of his discipline in interpreting the biblical record, Dever has pointed to multiple histories within the Bible, including the history of theology (the relationship between God and believers), political history (usually the account of "Great Men"), narrative history (the chronology of events), intellectual history ...
The Cone Nebula, sometimes referred to as the Jesus Christ Nebula because of its resemblance to the popular depictions of Jesus with his hands in a prayer position.. People have been found to perceive images with spiritual or religious themes or import, sometimes called iconoplasms or simulacra, in the shapes of natural phenomena.
The term p-process (p for proton) is used in two ways in the scientific literature concerning the astrophysical origin of the elements (nucleosynthesis).Originally it referred to a proton capture process which was proposed to be the source of certain, naturally occurring, neutron-deficient isotopes of the elements from selenium to mercury.
For example, the half-life of 256 No is almost three seconds, but that of 258 No is only 1.2 milliseconds. [ 73 ] [ 71 ] [ 72 ] This shows that at nobelium, the mutual repulsion of protons poses a limit to the region of long-lived nuclei in the actinide series. [ 75 ]