Diborane, \(\mathrm{B}_{2} \mathrm{H}_{6}\), is a highly unstable compound that reacts explosively with oxygen. Ethane, \(\mathrm{C}_{2} \mathrm{H}_{6}\), combines with oxygen only at elevated temperatures. Explain the differences in these two compounds.

: Diborane has an unusual structure with two bridging hydrogen atoms connecting the two boron atoms, which leads to three-center, two-electron bonds in addition to usual two-center, two-electron bonds between boron and terminal hydrogen atoms. This results in an electron-deficient system. In contrast, ethane has single covalent bonds between carbon and hydrogen and also between the two carbon atoms. The carbons are sp3-hybridized, and all the orbitals are filled with paired electrons, leading to a stable electron configuration.

: The three-center, two-electron bonds in diborane have weaker bond strengths compared to the single covalent bonds between carbon and hydrogen atoms in ethane. As a result, diborane is more prone to reactions than ethane, as it requires less energy to break the bonds and form new ones during a reaction.

: Diborane is an electron-deficient system, making it highly unstable and susceptible to reactions. The electron deficiency causes diborane to readily accept electrons from other compounds, such as oxygen, leading to an explosive reaction as diborane tries to fill its electron-deficient orbitals. On the other hand, ethane has a stable electron configuration with no electron deficiency. Ethane can react with oxygen, but the reaction is much slower and requires elevated temperatures. The higher temperature provides the necessary activation energy to initiate the reaction between ethane and oxygen. #Conclusion#: The differences in the reactivity of diborane and ethane with oxygen can be explained by their molecular structures, bond energies, and electron distributions. Diborane's electron-deficient system, weaker bond strength and unstable structure make it highly reactive and result in it reacting explosively with oxygen. Whereas, ethane's stable electron configuration, stronger covalent bonds, and requirement for higher activation energy results in a slower reaction at elevated temperatures.