boron: a trivalent metalloid element; occurs both in a hard black crystal and in the form of a yellow or brown powder
chemical element: any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter
sodium nitrite: nitrite used to preserve and color food especially in meat and fish products; implicated in the formation of suspected carcinogens