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Are homodesmotic reactions isodesmic reactions?

Answer 1

Ella Allen

Yes, homodesmotic reactions are a subset of isodesmic reactions.

An isodesmic reaction is a reaction that has the same number and type of bonds in the reactants and in the products.

An example of an isodesmic reaction is

Homodesmotic reactions are a subclass of isodesmic reactions.

Here, the reactants and products are even more similar. They must contain equal numbers of

atoms in the same state of hybridization
groups containing the same number of H atoms.
An example of a homodesmotic reaction is

The reactants and products contain equal numbers of bonds between carbons in the same state of hybridization and hydrogens bound to identical atom types.

#C_(sp^3)"-"O_(sp^3) # = 1

#C_(sp^3)"-"C_(sp^2) # = 1

#C_(sp^2)"-"O_(sp^3) # = 1

#C_(sp^2)"-"C_(sp^2) # = 7

#C_(sp^2)"="C_(sp^2) # = 6

#C_(sp^3)H_3# = 2

#C_(sp^2)H_2 # = 2

#C_(sp^2)H # = 9

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Answer 2

Nicholas Antonuccio

No, homodesmotic reactions are not the same as isodesmic reactions. While both involve comparing the energies of different molecular species, they are used in different contexts and have different purposes. Homodesmotic reactions involve comparing the energies of similar molecules or molecular fragments to determine the energetics of a particular chemical bond or group. Isodesmic reactions, on the other hand, involve comparing the energies of different molecules that have the same types and numbers of bonds in order to estimate the stability of a particular molecular structure or species.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.