electron tightly bound
"Having an electron tightly bound to an oxygen atom is like having a rock at the bottom of a hill. It's already at it's lowest energy point, so you can't get anymore energy out of it."
METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.