What's the difference between inexpiable and unatonable?

Inexpiable

Definition:

• (a.) Admitting of no expiation, atonement, or satisfaction; as, an inexpiable crime or offense.
• (a.) Incapable of being mollified or appeased; relentless; implacable.

Example Sentences:

Unatonable

Definition:

• (a.) Not capable of being brought into harmony; irreconcilable.
• (a.) Incapable of being atoned for; inexpiable.

Example Sentences: