We divided the space into its organic, organometallic and rare-earth (REE) subspaces (Figure , Methods). We found that the exponential expansion of the space, as observed since 1800, is largely dominated by the discovery of organic chemicals (Figure ). In contrast to the swift growth of the organic subspace, the organometallic and REE subspaces exhibit a distinct trend (Figure ). The former slightly increased its expansion until 2013 and ever since has slowed down its unfolding. REE chemical space, in turn, grows slowly.