What is the spacing between channels in the 2.4 GHz spectrum?

The recommended channels to use on 2.4 Ghz are Channel 1, 6 & 11 . As can be seen in the above diagram, these channels do not overlap into each other. In general 2.4 Ghz should be considered a legacy band for older devices that do not support 5 Ghz. It is often more crowded and less performant than 5 Ghz.

2.4 GHz (802.11b/g/n/ax) Fourteen channels are designated in the 2.4 GHz range, spaced 5 MHz apart from each other except for a 12 MHz space before channel 14. Nations apply their own RF emission regulations to the allowable channels, allowed users and maximum power levels within these frequency ranges.

The 2.4GHz band is broken up into 11 channels (1-11), each 20MHz wide.