Melting point

freezing pointmelting temperaturemeltingmelting pointsfreezingm.p.freeze pointfreezing pointsfreezing temperaturefusion point
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid.wikipedia
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Liquid

liquidsliquid phaseliquid state
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid.
When the liquid reaches its freezing point the molecules will usually lock into a very specific order, called crystallizing, and the bonds between them become more rigid, changing the liquid into its solid state (unless supercooling occurs).

Supercooling

supercooledsupercoolsupercooled water
Because of the ability of some substances to supercool, the freezing point is not considered as a characteristic property of a substance.
Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid or a gas below its freezing point without it becoming a solid.

State of matter

states of matterstatephysical state
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid.
When a solid is heated above its melting point, it becomes liquid, given that the pressure is higher than the triple point of the substance.

Mercury (element)

mercuryquicksilverHg
For example, the melting point and freezing point of mercury is 234.32 Kelvin (−38.83 °C or −37.89 °F).
It has a freezing point of −38.83 °C and a boiling point of 356.73 °C, both the lowest of any stable metal, although preliminary experiments on copernicium and flerovium have indicated that they have even lower boiling points (copernicium being the element below mercury in the periodic table, following the trend of decreasing boiling points down group 12).

Freezing

solidificationfrozenfreeze
For most substances, melting and freezing points are approximately equal.
For example, agar displays a hysteresis in its melting point and freezing point.

Tungsten

WwolframTungsten (W)
The chemical element with the highest melting point is tungsten, at 3414 C; this property makes tungsten excellent for use as filaments in light bulbs.
The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all the elements discovered, melting at 3422 °C (6192 °F, 3695 K).

Melting

moltenmeltmelted
For most substances, melting and freezing points are approximately equal.
This occurs when the internal energy of the solid increases, typically by the application of heat or pressure, which increases the substance's temperature to the melting point.

Water

H 2 OHOliquid water
In the presence of nucleating substances, the freezing point of water is not always the same as the melting point.
Specifically, at a standard pressure of 1 atm, water is a liquid between 0 and 100 C. Increasing the pressure slightly lowers the melting point, which is about -5 C at 600 atm and -22 C at 2100 atm.

Paraffin wax

paraffinwaxcandle wax
It is solid at room temperature and begins to melt above approximately 37 °C, and its boiling point is above 370 °C.

Temperature

temperaturesair temperaturewarm
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid.
For everyday applications, it is often convenient to use the Celsius scale, in which 0 degC corresponds very closely to the freezing point of water and 100 degC is its boiling point at sea level.

Beryllium

Be 7 BeBerillium
It has exceptional stiffness (Young's modulus 287 GPa) and a melting point of 1287 C. The modulus of elasticity of beryllium is approximately 50% greater than that of steel.

Potassium

KK + potassium ion
It is a soft solid with a low melting point, and can be easily cut with a knife.

Fahrenheit

°FFdegrees Fahrenheit
For example, the melting point and freezing point of mercury is 234.32 Kelvin (−38.83 °C or −37.89 °F).
On the Fahrenheit scale, the freezing point of water is 32 degrees Fahrenheit and the boiling point is 212 ℉ (at standard atmospheric pressure).

Lead

Pblead orelead mining
Lead is soft and malleable, and also has a relatively low melting point.

Nitrogen

NN 2 dinitrogen
Thus, for example, nitrogen occurs as diatomic molecules and therefore has very much lower melting (−210 °C) and boiling points (−196 °C) than the rest of its group, as the N 2 molecules are only held together by weak van der Waals interactions and there are very few electrons available to create significant instantaneous dipoles.

Sublimation (phase transition)

sublimationsublimessublimate
The often-cited carbon does not melt at ambient pressure but sublimes at about 3726.85 C; a liquid phase only exists above pressures of 10 MPa and estimated 4030-4430 C (see ).
Snow and ice sublime, although more slowly, at temperatures below the freezing/melting point temperature line at 0 °C for most pressures; see line below triple point.

Chemical element

elementelementschemical elements
The chemical element with the highest melting point is tungsten, at 3414 C; this property makes tungsten excellent for use as filaments in light bulbs.
Melting and boiling points, typically expressed in degrees Celsius at a pressure of one atmosphere, are commonly used in characterizing the various elements.

Gallium

GaGa 2 67 Ga
The melting point of gallium, at 302.9146 K (29.7646 °C, 85.5763 °F), is just above room temperature, and is approximately the same as the average summer daytime temperatures in Earth's mid-latitudes.

Indium

InIn 2 111 In
Like both, indium has a low melting point, 156.60 °C (313.88 °F); higher than its lighter homologue, gallium, but lower than its heavier homologue, thallium, and lower than tin.

Helium

Hehelium IIsuperfluid helium
At the other end of the scale, helium does not freeze at all at normal pressure even at temperatures arbitrarily close to absolute zero; a pressure of more than twenty times normal atmospheric pressure is necessary.
The solid has a sharp melting point and has a crystalline structure, but it is highly compressible; applying pressure in a laboratory can decrease its volume by more than 30%.

Gold

Aunative goldgold dust
These alloys can be produced to modify the hardness and other metallurgical properties, to control melting point or to create exotic colors.

Hysteresis

hysteretichysteresis loophysteresis loss
For example, agar melts at 85 °C (185 °F) and solidifies from 31 C; such direction dependence is known as hysteresis.
Hysteresis manifests itself in state transitions when melting temperature and freezing temperature do not agree.

Enthalpy of fusion

Std enthalpy change of fusionheat of fusionlatent heat of fusion
Differential scanning calorimetry gives information on melting point together with its enthalpy of fusion.
The temperature at which the phase transition occurs is the melting point or the freezing point, according to context.

Glass transition

glass transition temperaturevitrifiedvitrification
on heating they undergo a smooth glass transition into a viscous liquid.
It is always lower than the melting temperature, T m, of the crystalline state of the material, if one exists.

Differential scanning calorimetry

DSCDifferential Scanning Calorimetercalorimetry
Differential scanning calorimetry gives information on melting point together with its enthalpy of fusion.
Using this technique it is possible to observe fusion and crystallization events as well as glass transition temperatures T g .