As-Ba-Fe-K, K-x polyhedra

• As-Ba-Co-Fe-K
• As-Ba-Fe-K-Sn
• superconductivity
• electronic and electrical properties
• superconducting transition temperature
• magnetic properties
• values of superconducting transition temperature
• metalloid
• alkali
• alkaline
• disordered
• pnictogen
• tetragonal
• orthorhombic