Titrimetric microdetermination of yttrium and scandium: Disodium salt of rhodizonic acid as complexing agent

Yttrium and scandium are determined separately in micro amounts by forming and decomposing the complex, rare earth monosodium trirhodizonate, with ceric sulfate. The complexes between rare earths and disodium salt or rhodizonic acid are formed in the ratio of 1:3 at pH 4.9. Maximum error for yttrium and scandium is 1.7 and 1.1%, respectively. 0.0002 N H2SO4 is sufficient to affect the complexes. Interference by metal ions is, also, observed.