Compressional behaviors of ammonium phosphomolybdate hydrate (APMH) with different pressure media.

ABSTRACT: This study investigates the pressure-dependent structural response of ammonium phosphomolybdate hydrate (APMH) under four distinct pressure-transmitting media (PTMs): distilled water, methanol, ethanol, and silicone oil. Synchrotron X-ray diffraction combined with Rietveld refinement confirmed that APMH maintains the archetypal Keggin-type framework while incorporating approximately ten crystallographic water molecules per unit cell, distributed over two distinct coordination sites (OW1 and OW2). High-pressure diffraction experiments revealed pronounced PTM-dependent compressional behaviors. In water, APMH undergoes an abrupt 2.6% volume collapse near 2 GPa followed by framework stiffening, while silicone oil induces significant densification above ~4 GPa. By contrast, methanol and ethanol

SUBMITTER: Im J 

PROVIDER: S-EPMC12667314 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature