The crystal structure of Sr-hardystonite, Sr_2ZnSi_2O_7

摘要

A synthetic strontium isomorph (Sr_2ZnSi_2O_7) of the hardystonite structure (Ca_2ZnSi_2O_7) was investi-gated with X-ray powder diffraction. The average structure (S.G. P424_m), a = 8. 0007(1) A, c = 5.1722(1) A, was re-fined by Rietveld method and a R_F~2 = 0.0216 was achieved using 394 independent reflections. The results show that Srhardystonite has a melilite-type structure with no incommensurate modulations. Its geometrical and bonding features are consistent-with trends defined by the other so-called normal and modulated melilite structures.