Crystal structure and ferroelectricity of cesium dihydrogen phosphate CsH2PO4

Structural and dielectric studies have been performed on CsH2PO4 for scrutinizing the validity of the previously reported structure. It is found that the symmetry in the paraelectric state is not orthorhombic as previously assumed but monoclinic with the space group of C. The net configuration of hydrogen bond and the sequence of Cs and P are found to differ substantially from those of KH2PO4. Structural evidences combined with dielectric measurements indicate that the ferroelectricity of CsH2PO4 takes place through different atomic structure from that of KH2PO4 type ferroelectrics.