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search The crystal structure of ice VII  Ice VII is a cubic
crystalline form of ice. It can be formed from liquid water
above 3 GPa by lowering its temperature to room temperature, or
by decompressing (D2O) ice VI below 95 K. Ordinary water ice is
known as ice Ih, (in the Bridgman nomenclature). Different types
of ice, from ice II to ice XV, have been created in the
laboratory at different temperatures and pressures. Ice VII is
metastable over a wide range of temperatures and pressures and
transforms into low density amorphous ice (LDA) above 120K.[1]
Ice VII has a triple point with liquid water and Ice VI at 355 K
and 2.216 GPa, with the melt line extending to at least 715 K
and 10 GPa.[2] It can also be created by increasing the pressure
on ice VI at ambient temperature.[3]  Like the majority of ice
phases (including ice Ih), the hydrogen atom positions are
disordered.[4] In addition, the oxygen atoms are disordered over
multiple sites.[5][6][7] The