It would appear to be the case that scientists have managed to use Manganese to create magnetic silicon. This offers some interesting future paths with respect to data storage as well as "spintronics". The referencing article is here.
If this can be pushed to the limits then one can imagine a manganese atom within a silicon matrix whose spin state can be regulated. This might result in a memory storage device even more capable than that proposed by Drexler (e.g. Nanosystems Sec. 12.6.4). In part because there is a lot more Mn in the universe than F and so one simply has more memory storage capacity given the materials we have to work with.