On the high-pressure behavior of gobbinsite, the natural counterpart of the synthetic zeolite Na–P2

摘要: Abstract An in situ high-pressure single-crystal X-ray diffraction study of gobbinsite, the natural counterpart synthetic zeolite Na–P2, was carried out up to 4.3 GPa. No evidence amorphization observed within pressure-range investigated. Using a non-penetrating P -medium, two changes elastic behavior occur: first at 1.1–1.3 GPa and second 2.7–3.2 GPa. Birch-Murnaghan equations state truncated order were used fit experimental – V data three -ranges (i.e. 0.0001–1.1, 1.3–2.7 3.2–4.3 GPa), giving following isothermal bulk moduli ( K 0 ): 46.3(9), 52(8) 28(6) GPa, respectively. The unit-cell compression is significantly anisotropic. In response applied pressure, 8-membered ring channel parallel [1 0 0] undergoes significant increase ellipticity, whereas [0 1 0] shrinking towards circular shape P  ≥ 1.3 GPa. A partial re-organization H 2 O sites occurs between 1.1 1.3 GPa, new framework deformational modes onset ≥ 3.2 GPa, coupled with change coordination environment extraframework cations.