Boric acid chunks, also called hydrogen borate, boracic acid, orthoboric acid and acidum boricum, is a weak acid of boron often used as an antiseptic, insecticide, flame retardant, neutron absorber, or precursor to other chemical compounds. boric flakes acid has the chemical formula H3BO3 (sometimes written B(OH)3), and exists in the form of colorless crystals or a white powder that dissolves in water. When occurring as a mineral, boric flakes acid is called sassolite.