Crystal Structure and Theoretical Analysis of Cs2Ca3(SO4)4

Using the homovalent cation substitution strategy, a new sulfate, Cs2Ca3(SO4)(4), was successfully prepared using the spontaneous crystallization technique. A single-crystal structure measurement suggested that it crystallizes in space group P2(1)/c, with lattice parameters and molecules per unit cell of a = 9.9153(8), b = 9.3760(6), c = 9.8044(9), beta = 118.365(3)degrees, V = 802.04(11), and Z = 2. In the structure of Cs2Ca3(SO4)(4), CaO6 octahedra and SO4 tetrahedra are interconnected via a corner-sharing mode to form a three-dimensional framework comprising large cavities filled with Cs+ cations. First-principles calculations and diffuse reflectance spectra indicated that Cs2Ca3(SO4)(4) has a large energy band gap. Moreover, structural comparisons with similar compounds were conducted to explain the role of cations in tuning structural symmetry and birefringence. This paper helps to explain the size effect of cations on structural evolution.

Automated summary

By using the homovalent cation substitution strategy, a new sulfate compound, Cs2Ca3(SO4)(4), was successfully synthesized. The compound exhibits a unique crystal structure and a large energy band gap. The role of cations in tuning structural symmetry and birefringence was also analyzed through comparisons with similar compounds.