Alkali, Non-disordered, Nonmetal, Real part of permittivity

• As-H-K-O
• Li-O-Ta
• H-K-O-P
• Br-Co-Rb
• Na-Nb-O
• nonmetal
• non-disordered
• alkali
• chalcogen
• ferroelectric
• orthorhombic
• monoclinic
• tetragonal
• cubic
• trigonal