However, many of the physical properties of water and ice are controlled by the formation of hydrogen bonds between adjacent oxygen and hydrogen atoms while it is a weak bond, it is nonetheless critical in controlling the structure of both water and ice.Īn unusual property of water is that its solid form-ice frozen at atmospheric pressure-is approximately 8.3% less dense than its liquid form this is equivalent to a volumetric expansion of 9%. Ice possesses a regular crystalline structure based on the molecule of water, which consists of a single oxygen atom covalently bonded to two hydrogen atoms, or H–O–H. Physical properties The three-dimensional crystal structure of H 2O ice I h (c) is composed of bases of H 2O ice molecules (b) located on lattice points within the two-dimensional hexagonal space lattice (a). Ice is used in a variety of ways, including for cooling, for winter sports, and ice sculpting. The transition from ice to water is melting and from ice directly to water vapor is sublimation. It may also be deposited directly by water vapor, as happens in the formation of frost. The most common phase transition to ice I h occurs when liquid water is cooled below 0 ☌ ( 273.15 K, 32 ☏) at standard atmospheric pressure. Virtually all ice on Earth's surface and in its atmosphere is of a hexagonal crystalline structure denoted as ice I h (spoken as "ice one h") with minute traces of cubic ice, denoted as ice I c and, more recently found, Ice VII inclusions in diamonds. When cooled slowly, correlated proton tunneling occurs below −253.15 ☌ ( 20 K, −423.67 ☏) giving rise to macroscopic quantum phenomena. When water is cooled rapidly ( quenching), up to three types of amorphous ice can form depending on its history of pressure and temperature. Ice exhibits at least nineteen phases ( packing geometries), depending on temperature and pressure. It falls as snowflakes and hail or occurs as frost, icicles or ice spikes and aggregates from snow as glaciers and ice sheets. It is abundant on Earth's surface – particularly in the polar regions and above the snow line – and, as a common form of precipitation and deposition, plays a key role in Earth's water cycle and climate. Beyond the Solar System, it occurs as interstellar ice. In the Solar System, ice is abundant and occurs naturally from as close to the Sun as Mercury to as far away as the Oort cloud objects. Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-white color. As a naturally occurring crystalline inorganic solid with an ordered structure, ice is considered to be a mineral. Ice is water that is frozen into a solid state, typically forming at or below temperatures of 0 ° C, 32 ° F, or 273.15 K. The properties of ice vary substantially with temperature, purity and other factors. Linear thermal expansion coefficient ( α)Ġ.5057 − 0.001863 θ cal/(g K), θ = absolute value of temperature in ☌ An ice block, photographed at the Duluth Canal Park in MinnesotaĠ.0053(1 + 0.0015 θ) cal/(cm s K), θ = temperature in ☌