In my Guide to English Language Usage I say
information technology (IT): The word informatics appears in dictionaries but is not in common current use.
True the COED defines it as
the science of processing data for storage and retrieval
but I have always thought of it as falling into the category of what I call
dictionary words: Some words are found in dictionaries but are hardly ever used outside them. The synonyms architectural and western are almost always used instead of architectonic and occidental.
other examples being petroleum (excepting technical use and OPEC) and milliard.
Nevertheless, in a letter in today’s Guardian I read:
… expertise in [algorithms] is to be found predominantly in departments of computer science and informatics
I wonder what the status of this word is. It may have a precise technical meaning but I am sure that it is not used generally, as informática is in Spanish for example