Tell that to the children brain damaged from thimerosal, or to the people who ate too much mercury tainted fish. Take a look at the video from the University of Calcary that I linked in the main article. There, mercury is introduced to a neuron. You can see what happens to that neuron.
It is mercury ions which are toxic. Mercury IONS are not limited to mercury gas, and are available from virtually ANY mercury compound in solution. They are of course available from elemental mercury, as a mercury ion IS simply a mercury atom short of one electron.
As far as thimerasol, it is banned in the UK, Finland, and South Africa, and is classified as a highly acutely toxic, reproductive or developmental toxicant.