hyposulfurous acid


hy′po•sul•fur′ous ac′id

(ˈhaɪ pə sʌlˈfyʊər əs, -ˈsʌl fər əs, ˌhaɪ-)
n. an acid, H2S2O4, next in a series below sulfurous acid, known only in solution or in the form of its salts. [1810–20]