[en] Strontium zirconium disilicate, SrZrSi₂O₇, M_r=347.011, monoclinic, P2₁/c, T=295 K, a=7.7617(9), b=8.0713(10), c=10.0559(11) A, β=111.90(1) , V=584.51(7) A³, Z=4, D_x=3.935(1) Mg.m^-3, D_exp=3.928(22) Mg.m^-3 (T=294.85 K). Rietveld refinement using neutron powder diffraction data [λ=2.5717(3) A, F(000)=252.45 fm, μR=0.11, 295 contributing reflections] resulted in R_wp=2.72%. The structure can be described by alternately stacking layers containing the ZrO₆ octahedra and layers formed by the Si₂O₇ groups, parallel to (001). Elongated cages are formed for Sr with distorted SrO₈ dodecahedrons. The Si₂O₇ groups are in a nearly eclipsed configuration. The title compound is isostructural with the high temperature form of NaFeP₂O₇. (orig.)