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Consider the figure given in the previous answer: Due to a lone pair of $\ce{e-}$ and thus, due to lp-bp repulsions, all equatorial fluorine atoms will move upwards but still remain in a plane. Now, the $\ce{Br}$ will be out of that plane. This will cause the $\ce{F_{axial}-Br-F_{equatorial}}$ angle to reduce. I think $\ce{F_{equatorial}-Br-F_{equatorial}}$ ...


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Column 1 is the PDB ID, column 2 the chain ID, column 3 the residue number, column 4 the residue type, column 5 the secondary structure designation by the authors, column 6 the secondary structure of a 5-residue window centered on the residue in question. The remaining columns do appear to be distances. For example, columns 7, 8, and 9 are distances between ...


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(A) and (B) are answered well in the comments by Todd Minehardt and Techie5879. So, I'll summarise their points and clarify (C) to justify the answer (D). (A) $\ce{AX3}$ must be polar. Consider the case of $\ce{BH3}$ to disprove statement (A), since it is a non polar molecule with a trigonal planar structure (equal bond angles). (B) $\ce{AX3}$ must be planar....


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I am working on the secondary structure assignment/prediction (actually I am not sure) of proteins using machine learning. Secondary structure assignment is an automated method that defines the secondary structure (helix, sheet, loop) based on a known three-dimensional structure. Secondary structure prediction refers to taking the primary structure (the ...


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Structure assignment is relating e.g., a measured absorbance frequency (like a triplet in $\pu{^1H NMR}$), or a structural feature (like $\Phi$ and $\Psi$ in a Ramachandran plot) to a structure already known. It equally may be based on a putative / postulated structure; then, you compare e.g., how a simulated NMR spectrum is similar to the experimentally ...


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Phosphorus pentoxide is the common name of a chemical with molecular formula $\ce{P4O10}$. The common name is derived from its empirical formula, $\ce{P2O5}$. This white crystalline solid is the anhydride of phosphoric acid: It is a potent dehydrating agent and used as a powerful desiccant (as indicated by the exothermic nature of its hydrolysis) in limited ...


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This might be the mechanism based on the answer in your book. The isopropyl group might shift because of the resonance stabilization due to phenyl group and inductive effect of the methyl group in the resulting carbocation. This carbocation might be the most stable one compared to the other carbocations' possible.


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According to IUPAC Goldbook: A chemical species that behaves both as an acid and as a base is called amphoteric. This property depends upon the medium in which the species is investigated: $\ce{H2SO4}$ is an acid when studied in water, but becomes amphoteric in superacids. Most common example for amphoteric compound is water, which can act either as an ...


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This is simply a matter of how shapes are defined - and this is by positions of the nuclei only. Electron pairs are not taken into account, yet of course may explain why a certain shape is preferred. Say we take a look at a single Ne-atom - one would not call it an octahedron either.


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[...] but I'm confused about D and C - I feel they should be swapped. To my understanding, B and D share a more similar chemical environment (though not identical), specifically they are near a C-O bond, moving their chemical shift left. Also, the NMR peaks labelled D display a doublet, suggesting it is next to a single proton. Though B, C and D are all next ...


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