I was about to buy a box of 20 mule team borax until I noticed the ingredient "sodium borate", not tetraborate.. Is this the same thing? Plus there was no mention of decahydrate, penta, etc. At times companies can change their formulas. Calgon being one example I can think of. Does 20 mule team still use tetraborate?
You can ask that of seasoned chemists and they won't know the answer until they look it up. The chemistry of boron is truly bizzare. It has but three valence electrons and (almost) always manages to make four 2-electron bonds. Good question.