The writer is a science commentator

The idea struck Richard Robson, a British-born chemist at Melbourne University, as he was building large wooden models of crystals to show in undergraduate lectures. Diamond, for example, is a repeating pattern where each carbon atom binds to four other carbon atoms in a tetrahedral pattern — and easily duplicated with wooden balls representing carbon atoms and rods for chemical bonds.

What if, Robson pondered in the 1970s, metals and organic (carbon-based) molecules could link up to make similar kinds of 3D patterns? Around a decade later, his experiments showed that metal ions (metal atoms that carry a charge) and organic molecules could indeed form a viable crystal structure: an infinitely repeating pattern filled with vast spaces, making the material a porous sponge.