I am trying to teach myself about Electron Ionization, and am very confused about the formation of the CH4+ Ion.

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Do the dotted lines between the C and the H, and between the two Hydrogens indicate a resonance structure of sort? I have taken organic chemistry, but cannot wrap my head around this.


The dotted lines in this structure could be thought of as partial bonds. In other words, none of those three bonds has a bond order of 1 with two electrons attributable to that bond.

Another way to look at this structure is that the dashed lines represent multicenter bonding. A common example of multicenter bonding is diborane $\ce{B2H6}$. The structure of diborane features 3-center-2-electron bonds (often abbreviated 3c2e bonds - in this notation, a typical single sigma bond is a 2c2e bond) with two hydrogen atoms shared by both boron atoms: enter image description here

These bonds in $\ce{CH4+}$ could be considered a 3-centered-3-electron bond as originally each C-H bond would have had two electrons. The radical cation is one electron short, so there are only three electrons shared between those three atoms.


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