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  2. Mesomeric effect - Wikipedia

    en.wikipedia.org/wiki/Mesomeric_effect

    The +M effect, also known as the positive mesomeric effect, occurs when the substituent is an electron donating group. The group must have one of two things: a lone pair of electrons, or a negative charge. In the +M effect, the pi electrons are transferred from the group towards the conjugate system, increasing the density of the system.

  3. File:Mesomeric effect (–M) V.1.png - Wikipedia

    en.wikipedia.org/wiki/File:Mesomeric_effect_(–M...

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  4. Electrophilic aromatic directing groups - Wikipedia

    en.wikipedia.org/wiki/Electrophilic_aromatic...

    However, another effect that plays a role is the +M effect which adds electron density back into the benzene ring (thus having the opposite effect of the -I effect but by a different mechanism). This is called the mesomeric effect (hence +M) and the result for fluorine is that the +M effect approximately cancels out the -I effect.

  5. Hammett equation - Wikipedia

    en.wikipedia.org/wiki/Hammett_equation

    The next set of substituents are the halogens, for which the substituent effect is still positive but much more modest. The reason for this is that while the inductive effect is still negative, the mesomeric effect is positive, causing partial cancellation. The data also show that for these substituents, the meta effect is much larger than the ...

  6. Mesoionic compounds - Wikipedia

    en.wikipedia.org/wiki/Mesoionic_compounds

    Mesoionic compounds are a subclass of betaines. [1] Examples are sydnones and sydnone imines (e.g. the stimulant mesocarb ), münchnones , [ 1 ] [ 2 ] and mesoionic carbenes . The formal positive charge is associated with the ring atoms and the formal negative charge is associated either with ring atoms or an exocyclic nitrogen or other atom. [ 3 ]

  7. Chữ Nôm - Wikipedia

    en.wikipedia.org/wiki/Chữ_Nôm

    Chữ Nôm (𡨸喃, IPA: [t͡ɕɨ˦ˀ˥ nom˧˧]) [5] is a logographic writing system formerly used to write the Vietnamese language.It uses Chinese characters to represent Sino-Vietnamese vocabulary and some native Vietnamese words, with other words represented by new characters created using a variety of methods, including phono-semantic compounds. [6]

  8. Vietnamese units of measurement - Wikipedia

    en.wikipedia.org/wiki/Vietnamese_units_of...

    Originally, many thước of varying lengths were in use in Vietnam, each used for different purposes. According to Hoàng Phê (1988), [1] the traditional system of units had at least two thước of different lengths before 1890, [2] the thước ta (lit. "our ruler") or thước mộc ("wooden ruler"), equal to 0.425 metres (1 ft 4.7 in), and the thước đo vải ("ruler for measuring ...

  9. Ngô Đình Cẩn - Wikipedia

    en.wikipedia.org/wiki/Ngô_Đình_Cẩn

    Cẩn created the Popular Force organisation to operate in central Vietnam. [1] The Popular Force was an alternative to the Strategic Hamlet Program which was used on a much larger scale in the south by Nhu, who moved peasants into fortified camps in an attempt to isolate Viet Cong cadres from accessing the rural populace and intimidating or ...