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How is bond length of C-O and C-N same?
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How is bond length of C-O and C-N same?
Bond length is not just proportional to atom size. Determine by other things too. One other determining factor of bond length is electronegativity. Bigger the difference in electronegativity the tighter the bond. I made up a table and stuff to illustrate this point but, as it so happens, the electronegativities didn't explain the data super well either.
I think it's good to keep in mind (with this and also the rest of chem) these are trends and predictors. If you want to get reasonably close to real life you gotta use schrodinger's equation.
(Here's a table on atomic radii which also show that there's many different ways to measure the radius of an atom. One might line up better than another.)
Bond length is not just proportional to atom size. Determine by other things too. One other determining factor of bond length is electronegativity. Bigger the difference in electronegativity the tighter the bond. I made up a table and stuff to illustrate this point but, as it so happens, the electronegativities didn't explain the data super well either.
I think it's good to keep in mind (with this and also the rest of chem) these are trends and predictors. If you want to get reasonably close to real life you gotta use schrodinger's equation.
(Here's a table on atomic radii which also show that there's many different ways to measure the radius of an atom. One might line up better than another.)
The bond lengths given in your example tables are average bond lengths. That means, the actual bond length in given compound can be larger or smaller than the given value. Keep in mind that bond lengths are not just proportional to sizes of atoms involved making them. As pointed in the other answer, they are determine by other factors as well, which is a broad subject. One such factor is chemical structure of a compound. For example, let's compare chemical bonds in oxazole nucleus in oxazole derivatives with at least 2-substitutions (Ref.1-3):
These data demonstrate how bond lengths in oxazole ring deffere by its substitutions and attached ring systems. Even two $\ce{C^\mathrm{sp^2}-O^\mathrm{sp^3}}$ bonds in the same ring gives two different values (c.f., $\ce{O_{(1)}-C_{(2)}}$ and $\ce{C_{(5)}-O_{(1)}}$ values of each compound) because of substitution differences.
References:
Boon-Chuan Yip, Hoong-Kun Fun, Siang-Guan Teoh, Omar Bin Shawkataly, "Structure of 2-(1-naphthyl)-5-phenyl-1,3-oxazole ($\alpha$-NPO)," Acta Cryst. C1993, C49, 1532-1534 (https://doi.org/10.1107/S0108270193001192).
A. Albinati, M. G. Marcon, P. Traldi, P. Cavoli, "The structure of 2-amino-1,3-oxazole," Acta Cryst. B1981, B37, 2090-2092 (https://doi.org/10.1107/S0567740881008078).
P. Luger, G. Griss, R. Hurnaus, G. Trummlitz, "The $\alpha_2$-adrenoceptor agonists B-HT 920, B-HT 922, and B-HT 958, a comparative X-ray and molecular-mechanics study," Acta Cryst. B1986, B42, 478-490 (https://doi.org/10.1107/S0108768186097859).
The bond lengths given in your example tables are average bond lengths. That means, the actual bond length in given compound can be larger or smaller than the given value. Keep in mind that bond lengths are not just proportional to sizes of atoms involved making them. As pointed in the other answer, they are determine by other factors as well, which is a broad subject. One such factor is chemical structure of a compound. For example, let's compare chemical bonds in oxazole nucleus in oxazole derivatives with at least 2-substitutions (Ref.1-3):
These data demonstrate how bond lengths in oxazole ring deffere by its substitutions and attached ring systems. Even two $\ce{C^\mathrm{sp^2}-O^\mathrm{sp^3}}$ bonds in the same ring gives two different values (c.f., $\ce{O_{(1)}-C_{(2)}}$ and $\ce{C_{(5)}-O_{(1)}}$ values of each compound) because of substitution differences.
References:
Boon-Chuan Yip, Hoong-Kun Fun, Siang-Guan Teoh, Omar Bin Shawkataly, "Structure of 2-(1-naphthyl)-5-phenyl-1,3-oxazole ($\alpha$-NPO)," Acta Cryst. C1993, C49, 1532-1534 (https://doi.org/10.1107/S0108270193001192).
A. Albinati, M. G. Marcon, P. Traldi, P. Cavoli, "The structure of 2-amino-1,3-oxazole," Acta Cryst. B1981, B37, 2090-2092 (https://doi.org/10.1107/S0567740881008078).
P. Luger, G. Griss, R. Hurnaus, G. Trummlitz, "The $\alpha_2$-adrenoceptor agonists B-HT 920, B-HT 922, and B-HT 958, a comparative X-ray and molecular-mechanics study," Acta Cryst. B1986, B42, 478-490 (https://doi.org/10.1107/S0108768186097859).
Bond length is not just proportional to atom size. Determine by other things too. One other determining factor of bond length is electronegativity. Bigger the difference in electronegativity the tighter the bond. I made up a table and stuff to illustrate this point but, as it so happens, the electronegativities didn't explain the data super well either.
I think it's good to keep in mind (with this and also the rest of chem) these are trends and predictors. If you want to get reasonably close to real life you gotta use schrodinger's equation.
(Here's a table on atomic radii which also show that there's many different ways to measure the radius of an atom. One might line up better than another.)
Bond length is not just proportional to atom size. Determine by other things too. One other determining factor of bond length is electronegativity. Bigger the difference in electronegativity the tighter the bond. I made up a table and stuff to illustrate this point but, as it so happens, the electronegativities didn't explain the data super well either.
I think it's good to keep in mind (with this and also the rest of chem) these are trends and predictors. If you want to get reasonably close to real life you gotta use schrodinger's equation.
(Here's a table on atomic radii which also show that there's many different ways to measure the radius of an atom. One might line up better than another.)
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The bond lengths given in your example tables are average bond lengths. That means, the actual bond length in given compound can be larger or smaller than the given value. Keep in mind that bond lengths are not just proportional to sizes of atoms involved making them. As pointed in the other answer, they are determine by other factors as well, which is a broad subject. One such factor is chemical structure of a compound. For example, let's compare chemical bonds in oxazole nucleus in oxazole derivatives with at least 2-substitutions (Ref.1-3):
$$ \begin{array}{c|ccc} \text{Bonds} & \text{Bond length in $\bf{I}$} & \text{Bond length in $\bf{II}$} & \text{Bond length in $\bf{III}$} \\ \hline \ce{O_{(1)}-C_{(2)}} & \pu{1.370 \mathring{A}} & \pu{1.356 \mathring{A}} & \pu{1.356 \mathring{A}} \\ \ce{C_{(2)}-N_{(3)}} & \pu{1.299 \mathring{A}} & \pu{1.294 \mathring{A}} & \pu{1.297 \mathring{A}} \\ \ce{N_{(3)}-C_{(4)}} & \pu{1.382 \mathring{A}} & \pu{1.410 \mathring{A}} & \pu{1.405 \mathring{A}} \\ \ce{C_{(4)}-C_{(5)}} & \pu{1.333 \mathring{A}} & \pu{1.310 \mathring{A}} & \pu{1.332 \mathring{A}} \\ \ce{C_{(5)}-O_{(1)}} & \pu{1.375 \mathring{A}} & \pu{1.399 \mathring{A}} & \pu{1.402 \mathring{A}} \\ \hline \end{array} $$
These data demonstrate how bond lengths in oxazole ring deffere by its substitutions and attached ring systems. Even two $\ce{C^\mathrm{sp^2}-O^\mathrm{sp^3}}$ bonds in the same ring gives two different values (c.f., $\ce{O_{(1)}-C_{(2)}}$ and $\ce{C_{(5)}-O_{(1)}}$ values of each compound) because of substitution differences.
References:
The bond lengths given in your example tables are average bond lengths. That means, the actual bond length in given compound can be larger or smaller than the given value. Keep in mind that bond lengths are not just proportional to sizes of atoms involved making them. As pointed in the other answer, they are determine by other factors as well, which is a broad subject. One such factor is chemical structure of a compound. For example, let's compare chemical bonds in oxazole nucleus in oxazole derivatives with at least 2-substitutions (Ref.1-3):
$$\begin{array}{c|ccc}\text{Bonds} & \text{Bond length in $\bf{I}$} & \text{Bond length in $\bf{II}$} & \text{Bond length in $\bf{III}$} \\\hline\ce{O_{(1)}-C_{(2)}} & \pu{1.370 \mathring{A}} & \pu{1.356 \mathring{A}} & \pu{1.356 \mathring{A}} \\\ce{C_{(2)}-N_{(3)}} & \pu{1.299 \mathring{A}} & \pu{1.294 \mathring{A}} & \pu{1.297 \mathring{A}} \\\ce{N_{(3)}-C_{(4)}} & \pu{1.382 \mathring{A}} & \pu{1.410 \mathring{A}} & \pu{1.405 \mathring{A}} \\\ce{C_{(4)}-C_{(5)}} & \pu{1.333 \mathring{A}} & \pu{1.310 \mathring{A}} & \pu{1.332 \mathring{A}} \\\ce{C_{(5)}-O_{(1)}} & \pu{1.375 \mathring{A}} & \pu{1.399 \mathring{A}} & \pu{1.402 \mathring{A}} \\\hline\end{array}$$
These data demonstrate how bond lengths in oxazole ring deffere by its substitutions and attached ring systems. Even two $\ce{C^\mathrm{sp^2}-O^\mathrm{sp^3}}$ bonds in the same ring gives two different values (c.f., $\ce{O_{(1)}-C_{(2)}}$ and $\ce{C_{(5)}-O_{(1)}}$ values of each compound) because of substitution differences.
References:
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