BiCe(SO4)3(H2O)3: a non-centrosymmetric bismuth cerium(III) sulfate with second-order nonlinear optical activity arising from strategic heterovalent cationic substitution.

Non-centrosymmetric (NCS) rare-earth (RE) nonlinear optical (NLO) crystals attract wide attention, yet fabricating RE sulfates with strong second harmonic generation (SHG) is tough. Herein, heterovalent Bi3+ with stereochemically active lone pairs is doped into RE sulfate frameworks, yielding novel NCS BiCe(SO4)3(H2O)3 hydrothermally. It shows solar-blind transparency together with a strong SHG response of 1.8 × KH2PO4 (KDP), the highest among Ce(III) sulfates, offering a valid NLO material design route.