Further Example of Diphosphates: Synthesis and Characterization of K2Li2P2O7

By the application of cation substitution, a new mixed‐alkali metal diphosphate, K₂Li₂P₂O₇, was successfully synthesized through high temperature solution method for the first time. The single‐crystal X‐ray structural analysis shows that it crystallizes in the monoclinic space group C2/c (no. 15), with lattice constants a = 9.814(3) Å, b = 5.5163(15) Å, c = 13.538(4) Å, Z = 4, and β = 110.47(2)°. Its open cage‐like _∞³Li₂(P₂O₇)]^2– framework is built up from alternating arrangement of Li₂O₆ and P₂O₇ dimers that form eight and twelve‐membered‐ring channels along the 010] direction, and the K atoms are entrapped in the larger twelve‐membered‐ring channels. Detailed structure comparisons in the N₄P₂O₇ (N = mixed alkali metals) family are discussed. In addition, the structural validity was verified through the IR spectrum. Thermal analyses and UV/Vis/NIR diffuse reflectance spectrum are also performed on the reported compound.