  Water is ubiquitously important but least known. This perspective features
the latest finding of two exotic forms of water called quasisolid and
supersolid phases due to the cooperativity and disparity of the O:H-O bond in
its segmental length, energy, and specific heat when subjected to thermal,
electric, and undercoordination perturbation. The quasisolid (QS) phase only
appears at temperatures between melting and ice nucleation, regardless of
sample size, and this phase has a negative thermal expansivity (NTE). However,
polarization or molecular undercoordination creates the supersolid phase in
skins of water and ice, droplets, ionic hydration cells, and volumetric water
with a current flow or under a 106 eV/cm electric bias. This phase is
characterized by ~10% H-O bond contraction and vibrating at ~3450 cm-1. The
supersolid has unique properties such as high elasticity, mechanical strength,
optical reflectivity, structure order, thermal stability, diffusivity,
catalytic activity, and chemical reactivity. Liquid-QS-Ice transition with QS
phase energy absorption occurs for water due to H-O bond contraction during
thermal decay but not for the supersolid phase of saturated NaCl solution. The
NTE of the QS fosters ice buoyancy and the supersolidity endows ice
slipperiness, supercooling, superheating, premelting, low-temperature fiber
elasticity, water bridge, and warm water fast cooling, as well as on water
chemistry.
