Sm3S3BO3: The First Sulfide Borate without S–O and B–S Bonds

An unprecedented quaternary sulfide borate, Sm3S3BO3 (1), was obtained via a high-temperature solid-state synthesis method. It crystallizes in the triclinic space group P1̅, and its 3D structure features a 2D (Sm2S2)∞ wrinkled layer and a 1D (SmS)∞ ladderlike chain bridged by trigonal-planar (BO3)3– through Sm–O bonds, demonstrating the first sulfide borate without S–O and B–S bonds. Its optical energy gap is measured to be around 2.5 eV and verified by electronic structure calculation.