a potassium is a mean of preposition
potassium_32 is potassium. preposition is function_word. locative_preposition is spatial_preposition. spatial_preposition is preposition. atelic_directional_preposition is spatial_preposition. directional_preposition is spatial_preposition. atelic_directional_preposition is not spatial_preposition. preposition_of is preposition. spatial_preposition is not preposition. potassium_phosphate is salt.