cyanomethemoglobin

noun

cy·​a·​no·​met·​he·​mo·​glo·​bin ˌsī-ə-ˌnō-(ˈ)met-ˈhē-mə-ˌglō-bən 

variants or cyanmethemoglobin

ˌsī-ˌan-(ˈ)met-, ˌsī-ən- 

or chiefly British cyanomethaemoglobin or cyanmethaemoglobin

: a bright red crystalline compound formed by the action of hydrogen cyanide on methemoglobin in the cold or on oxyhemoglobin at body temperature