“…Neutron powder diffraction experiments performed on the monoclinic polymorph of phosphoric acid showed that it converts to a more efficiently packed, and thus harder, orthorhombic phase during pressure release at 1.97 GPa; the bulk moduli being 13.81(15) and 17.61(36) GPa, respectively, following the expected trend. 71 A similar study performed on the orthorhombic form of Sc 2 W 3 O 12 showed that it undergoes a phase transition between 0.25 and 0.3 GPa to a softer monoclinic phase, with bulk moduli respectively of 32(2) and 11.8(8) GPa. 72 A Raman and synchrotron X-ray diffraction study on three polymorphs of alane, AlH 3 (orthorhombic γ, trigonal α, cubic β), found their bulk moduli to be 42(2), 45(3) and 58(4) GPa, respectively.…”