Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
expĭātĭo, ōnis, f. [expio], satisfaction, atonement, expiation (rare but class.): at vero scelerum in homines atque impietatum nulla expiatio est, * Cic. Leg. 1, 14, 40: foederis rupti, Liv. 9, 1, 4; Vulg. Exod. 29, 36 al.