I am adopted, and when I was young I used to speak of the "adoptiation agency." For some reason, it didn't occur to me that I could have said simply "adoption agency"; but why do we add -at- to orient but not adopt? (Okay, I threw in -iat-, and, again, "adoptation" would not sound nearly as good.)
Another word that adds -at- is preventative. At the oriention this morning, I noticed they used the word "preventive" to describe certain kinds of health care that we employees are eligible for, so I thought maybe preventative was just incorrect, along the lines of adoptiation. But, no, it appears to be a legitimate alternative, sometimes with a slightly different meaning (preventative is a noun describing a procedure in preventive medicine), but sometimes with the identical meaning.