High Pressure Behavior of Mascagnite from Single Crystal Synchrotron X-ray Diffraction Data

High-pressure synchrotron X-ray diffraction was carried out on a single crystal of mascagnite, compressed in diamond anvil cell. The sample maintained its structure up to ~18 GPa. volume–pressure data were fitted by third-order Birch–Murnaghan equation state (BM3-EOS) yielding K0 = 20.4(7) GPa, K’0 6.1(2), and V0 499(1) Å3, as suggested the F-f plot. axial compressibilities, calculated with BM3-EOS, K0a 35(3), K’0a 7.7(7), K0b 10(3), K’0b 7(1), K0c 25(1), K’0c 4.3(2) moduli measured using BM2-EOS fixing equal 4, 52(2), 20 (1), 29.6(4) anisotropic ratio K0a:K0b:K0c 1:0.4:0.5. evolution lattice geometrical parameters indicated no phase transition until 17.6 Sulphate polyhedra incompressible density increase 30% compared investigated pressure should be attributed reduction weaker hydrogen bonds. In contrast, some them, directed along [100], very short at room temperature, below 2 Å, showed low compressibility. This configuration explains compressional behavior lowest compressibility axis.