Synthesis and crystal structure of a polar layered chloride perchlorate, BaCl(ClO₄)·H₂O (1) where the chlorine atoms play two crystallographically different roles with Cl^VII centering the anionic [ClO₄]⁻ tetrahedra, and Cl^{− I} centering the edge-sharing [ClBa₄]^{7 +} anion-centered tetrahedra is reported. SHG measurements confirm SHG activity of 1 as 5–6 SiO₂ units. The polarity in the structure of 1 is resulted from the orientation of the perchlorate anions.