This question can be answered by counting the number of coupled P spins with multiple quantum NMR (MQ-NMR) spin counting (MQ-SC) . In fact, MQ-SC might be the only technique available to count the number of coupled nuclei in soluble, small clusters of magnetically indistinct environments. Notably, while spin counting has been utilized to characterize amorphous or crystalline solids , it has never been applied to characterize the structure of soluble assemblies and clusters in solution upon vitrification.