Although it has few uses, one of its salts, sodium selenate is used in the production of glass and animal feeds.

[5] It is prepared by oxidising selenium compounds in lower oxidation states.

One method involves the oxidation of selenium dioxide with hydrogen peroxide: Unlike the production sulfuric acid by hydration of sulfur trioxide, the hydration of selenium trioxide is an impractical method.

[7] To obtain the anhydrous acid as a crystalline solid, the resulting solution is evaporated at temperatures below 140 °C (413 K; 284 °F) in a vacuum.

[4] Treatment with fluorosulfuric acid gives selenoyl fluoride:[8] Hot, concentrated selenic acid reacts with gold, forming a reddish-yellow solution of gold(III) selenate:[10] Selenic acid is used as a specialized oxidizing agent.