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  2. Oxonium ion - Wikipedia

    en.wikipedia.org/wiki/Oxonium_ion

    Extreme acidity, heat, and dehydrating conditions are usually required. Other hydrocarbon oxonium ions are formed by protonation or alkylation of alcohols or ethers (R−C− + −R 1 R 2). Secondary oxonium ions have the formula R 2 OH +, an example being protonated ethers. Tertiary oxonium ions have the formula R 3 O +, an example being ...

  3. Resonance (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Resonance_(chemistry)

    Contributing structures of the carbonate ion. In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures (or forms, [1] also variously known as resonance structures or canonical structures) into a resonance hybrid (or hybrid structure) in valence bond theory.

  4. Mechanical resonance - Wikipedia

    en.wikipedia.org/wiki/Mechanical_resonance

    Mechanical resonance is the tendency of a mechanical system to respond at greater amplitude when the frequency of its oscillations matches the system's natural frequency of vibration (its resonance frequency or resonant frequency) closer than it does other frequencies. It may cause violent swaying motions and potentially catastrophic failure in ...

  5. Oxime - Wikipedia

    en.wikipedia.org/wiki/Oxime

    In organic chemistry, an oxime is an organic compound belonging to the imines, with the general formula RR’C=N−OH, where R is an organic side-chain and R' may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. O-substituted oximes form a closely related family of compounds.

  6. Mesomeric effect - Wikipedia

    en.wikipedia.org/wiki/Mesomeric_effect

    In chemistry, the mesomeric effect (or resonance effect) is a property of substituents or functional groups in a chemical compound.It is defined as the polarity produced in the molecule by the interaction of two pi bonds or between a pi bond and lone pair of electrons present on an adjacent atom. [1]

  7. Metal roof - Wikipedia

    en.wikipedia.org/wiki/Metal_roof

    A metal roof is a roofing system featuring metal pieces or tiles exhibiting corrosion resistance, impermeability to water, and long life. It is a component of the building envelope . The metal pieces may be a covering on a structural, non-waterproof roof, or they could be self-supporting sheets.

  8. Lewis structure - Wikipedia

    en.wikipedia.org/wiki/Lewis_structure

    Expressing resonance when drawing Lewis structures may be done either by drawing each of the possible resonance forms and placing double-headed arrows between them or by using dashed lines to represent the partial bonds (although the latter is a good representation of the resonance hybrid which is not, formally speaking, a Lewis structure ...

  9. Cyanate - Wikipedia

    en.wikipedia.org/wiki/Cyanate

    The cyanate ion can bridge between two metal atoms by using both its donor atoms. For example, this structure is found in the compound [Ni 2 (NCO) 2 2](BPh 4) 2. In this compound both the Ni−N−C unit and Ni−O−C unit are bent, even though in the first case donation is through the nitrogen atom. [16]