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  2. Fluorination by sulfur tetrafluoride - Wikipedia

    en.wikipedia.org/wiki/Fluorination_by_sulfur...

    For carboxlic acids, the first step gives the acyl fluorides, in keeping with the tendency of SF 4 to fluorinate acidic hydroxyl groups: SF 4 + RCO 2 H → SOF 2 + RC(O)F + HF. Similarly SF 4 converts sulfonic acids to sulfonyl fluorides: SF 4 + RSO 3 H → SOF 2 + RSO 2 F + HF. Aldehydes and ketones convert to geminal difluorides: SF 4 + R 2 ...

  3. Orbital hybridisation - Wikipedia

    en.wikipedia.org/wiki/Orbital_hybridisation

    Chemist Linus Pauling first developed the hybridisation theory in 1931 to explain the structure of simple molecules such as methane (CH 4) using atomic orbitals. [2] Pauling pointed out that a carbon atom forms four bonds by using one s and three p orbitals, so that "it might be inferred" that a carbon atom would form three bonds at right angles (using p orbitals) and a fourth weaker bond ...

  4. Isovalent hybridization - Wikipedia

    en.wikipedia.org/wiki/Isovalent_hybridization

    In chemistry, isovalent or second order hybridization is an extension of orbital hybridization, the mixing of atomic orbitals into hybrid orbitals which can form chemical bonds, to include fractional numbers of atomic orbitals of each type (s, p, d). It allows for a quantitative depiction of bond formation when the molecular geometry deviates ...

  5. Orbital overlap - Wikipedia

    en.wikipedia.org/wiki/Orbital_overlap

    In chemical bonds, an orbital overlap is the concentration of orbitals on adjacent atoms in the same regions of space. Orbital overlap can lead to bond formation. Linus Pauling explained the importance of orbital overlap in the molecular bond angles observed through experimentation; it is the basis for orbital hybridization.

  6. Localized molecular orbitals - Wikipedia

    en.wikipedia.org/wiki/Localized_molecular_orbitals

    For instance, the lone pairs of water are usually treated as two equivalent sp x hybrid orbitals, while the corresponding "nonbonding" orbitals of carbenes are generally treated as a filled σ(out) orbital and an unfilled pure p orbital, even though the lone pairs of water could be described analogously by filled σ(out) and p orbitals (for ...

  7. Ortho effect - Wikipedia

    en.wikipedia.org/wiki/Ortho_effect

    When protonated, the nitrogen in the amino group changes its orbital hybridization from sp 2 to sp 3, becoming non-planar. This leads to steric hindrance between the ortho-substituted group and the hydrogen atom of the amino group, reducing the stability of the conjugate acid and consequently decreasing the pH of substituted aniline.

  8. Migrant teen killed, another injured, after being asked if ...

    www.aol.com/migrant-teens-stabbed-nyc-1...

    Officials say two migrant teens were victims in a New York City stabbing, one fatally, after the teens were asked if they spoke English and they responded that they didn't.

  9. Protein contact map - Wikipedia

    en.wikipedia.org/wiki/Protein_contact_map

    A protein contact map represents the distance between all possible amino acid residue pairs of a three-dimensional protein structure using a binary two-dimensional matrix. For two residues i {\displaystyle i} and j {\displaystyle j} , the i j {\displaystyle ij} element of the matrix is 1 if the two residues are closer than a predetermined ...