Constructions of new families of nonbinary CSS codes

New families of good q -ary ( q is an odd prime power) Calderbank–Shor–Steane (CSS) quantum codes derived from two distinct classical Bose–Chaudhuri–Hocquenghem (BCH) codes, not necessarily self-orthogonal, are constructed. These new families consist of CSS codes whose parameters are better than the ones available in the literature and comparable to the parameters of quantum BCH codes generated by applying the q -ary Steane’s enlargement of CSS codes.