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To kill a hanging job, I use Ctrl+c, to send an interrupt signal to the hanging job. Sometimes this wouldn't stop the job, at least not immediately. I can then use Ctrl+z to suspend the job and then kill it with kill %1 (or whatever the number of the job is).

Why is Ctrl+z more powerful than Ctrl+c in interfering with a job? Sometimes, not even Ctrl+z works. Are there other key combinations one could use in such situations?

I tried stty -a, but none of the other listed key combinations do anything for me.

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Ctrl+C (control character intr): It will send SIGINT signal to a process and usually application gets abort but the application can handle this signal. For example you can handle a signal with signal() function in C Language.

Ctrl+Z (control character susp): It will send SIGTSTP signal to a process to put it in background and like SIGINT it can be handle.

The process will not kill immediately with Ctrl+C if it has wait I/O and you have to wait to finish its I/O and then the application will terminate from memory. ‌
But Ctrl+Z will pause your process and its I/Os. Technically the operating system will not give it CPU time and if you kill the background process, it may lose some I/O and data.

For force killing a process you have to SIGKILL or signal number 9 which is most powerful signal - the operating system will kill it immediately, but you may lose data, as the program will have no way to react to this signal.

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