Phosphate

Phosphate is a molecule containing a phosphorus atom. Its chemical formula is HPO.

When heated (perhaps on the side of some ancient volcano on the young Earth) phosphate molecules can join together by dry-joining to form chains.

Phosphate is an acid. When placed in water it looses a proton it becomes negatively charged. In a chain of phosphates, each phosphate can loose become charged. These charges repel each other. But the covalent bond is stronger than the force of repulsion, so the chain does not break apart. Instead it gains springiness in the bond between phosphates.

This spring is the driving force of many of life's processes. Phosphate is used by life to carry energy from one molecule to another in ATP. It is also part of RNA and DNA.

Because it is part of the fundamental molecules of life, we can be fairly sure phosphate was used when life was first evolving, soon after the Earth was formed.