Used as a precipitating agent in analytical chemistry for the detection and quantification of potassium ions. Forms a characteristic crystalline precipitate with potassium in neutral or slightly basic solutions, making it valuable in qualitative inorganic analysis. Also employed in some histological staining procedures to demonstrate potassium distribution in tissues. Its selectivity for potassium over other alkali metals is limited, so sample pretreatment is often required to remove interfering ions like sodium.