An atomic integral dornain R is a half-factorial dornain (HFD) if whenever x₁…x_m = y₁…y_n with each x_i, y_j ∈ R irreducible, then m = n. In this paper, we show that if R[X] is an HFD, then Cl_t(R) ◎ Cl_t(R[X]), and if G₁ and G₂ are torsion abelian groups, then there exists a Dedekind HFD R such that Cl(R) = G₁◎G₂.
