“…Structure strain is usually released through structure symmetry lowering and polyhedral distortion/rotation, which was observed indeed in numerous "114" oxides such as LnBaFe 4 O 7 (Ln = Y, Dy-Lu) 23,37 , LnBaCo 4 O 7 (Ln = Ca, Y, Tb-Lu) [38][39][40] , and MAZn 2 Ga 2 O 7 (M = Ca 2+ , Sr 2+ ; A = Sr 2+ , Ba 2+ ) 18 . Herein, the structure strain of CaBa 1−x Pb x Zn 2 Ga 2 O 7 is released without a significant distortion of the [Zn 2 Ga 2 O 7 ] 4− framework, that is, the stereochemically active LP effect of Pb 2+ helps the release of the structure strain.…”