If chemistry is, ultimately, about the bonds between things, Chemistry is about when those bonds are broken and how they break, I suppose.
Is it enough to feel something inside, or is saying it out loud a necessary part of the bonding process? If it is enough, what does that say - as the person who wants or needs to hear it out loud - about the trust required? If it isn’t, then what is that catalyst doing?
There’s a lot here about the knock-on effects of upbringing, the relationships and environment around you that dictate the way you see the world, which the protagonist is loathe to explore in reluctant therapy sessions, in sharp contrast (or is it?) to lab work as a chemist, the understanding of cause and effect, the laws of thermodynamics.
I feel - and this is my fault, not Wang’s, I think - inured to this type of novel, for the moment. The question of whether it’s profound or just ambiguous, and whether it matters or not if the author knows what they’re doing.
There’s probably also something interesting in the delayed mirroring of the protagonist and the best friend, the decision as to what it means to be happy, why and when to accept or not accept what you have in front of you, and how you need to see that in someone else first.