i before e except after c
Most people know the spelling rule about i before e except after c, as in the following words:
The rule only applies when the sound represented is ‘ee,’ however. It does not apply to words such as science or efficient, in which the -ie- combination does follow the letter c but is not pronounced ‘ee’.
Neither does the rule apply to any word without the ee sound, even when there is no c involved. For example:
-ei- (not pronounced ee)
There are a few exceptions to the general i before e rule, even when the sound is ‘ee’. Examples include seize, weird, and caffeine. There is nothing for it but to learn how to spell these words, checking in a dictionary until you are sure about them.