Difference between Eubacteria and Eubacterium

What is the difference between Eubacteria and Eubacterium?

Eubacteria as a noun is any bacterium considered to be within the obsolete taxonomic subkingdom eubacteria while Eubacterium as a noun is any bacterium considered to be within the obsolete domain eubacteria

We hope you now know whether to use Eubacteria or Eubacterium in your sentence.