Magnesium is Mg.

perhaps "T" is shorthand for a toluene molecule? And "R" is perhaps Rigglium (a long shot, I know -- I haven't done any chemistry since 12th grade, over 20 years ago, so they probably haven't named any elements for me recently).

Did they finally scrap that method of naming the elements one-oh-fivium and such (albeit in Latin)? That was the styoooopidest idea.

Alex