Exactly as the title asks.

Pure oxygen is generally represented as O2 yet oxygen is an element of the periodic table. Why is it O2 and not just O?

  • Jeena
    1•1 year ago

    My guess is that it’s because most of the oxygen on earth can be found in its O2 form.

      • Jeena
        7•1 year ago

        That’s an interesting thought.

        Water on earth: 1,386 million km3 Air on earth: 5.1 million km3

        880 grams of Oxygen per liter of water 276 mg/liter of air

        From that follows that you’re right and there a several magnitudes more O in water compared to O in air.

        • @[email protected]
          8•1 year ago

          Wait until you find out the composition of the Earth’s crust and mantle

          (Spoiler: about 45% of them is oxygen)

          • @Klear
            5•1 year ago

            - Wait, it’s all oxygen?

            - Always have been.

          • @Chee_Koala
            1•1 year ago

            Is most of the rest silicates? Saw a post about environmentally friendlier concrete made mostly from silicate rock, and I thought: Is that good? Is there so much of that type? 15m internet research gave me reason to believe that yes; most rock is silicate rock on earth. Your information about oxygen contents in crust and mantle indicates you might be able to confirm or deny this.

            • @[email protected]
              2•1 year ago

              (Disclaimer: I’m not an expert, I just googled a little bit before posting that message. Fact-checking is welcome.)

              “Is most of the rest silicates?” The question is ill-posed, because it mixes elements with compounds. Specifically, silicates contain oxygen so they can’t be counted separately.

              If we go by elements, we already said that oxygen is the most abundant. The rest of the crust is mostly silicon (28%), aluminium (8.2%), iron (5.6%) and more stuff. The rest of the mantle is mostly magnesium (22.8%) and silicon (21.5%).

              But most elements don’t remain isolated, they react and form compounds. Those made primarily by silicon and oxygen are known as silicates, and they are indeed the most common type of rock in the crust and mantle.

              So yes, there is plenty of silicate material if one wants to use it for construction. I have no idea how good it is compared to current materials, however.