what words break the i before e rule
I before E except after C "I before E, except after C" is a mnemonic rule of thumb for English spelling. If one is unsure whether a word is spelled with the sequence ei or ie, the rhyme suggests that the correct order is ie unless the preceding letter is c, in which case it is ei. For example:
Email address Earlier forms of email addresses on other networks than the Internet included other notations, such as that required by X.400, and the UUCP bang path notation, in which the address was given in the form of a sequence of computers through which the message should be relayed. This was widely used for several years, but was superseded by the Internet standards promulgated by the Internet Engineering Task Force (IETF).