# Tag Info

Accepted

### How do you melt metals with super high melting points?

Tungsten's melting point of 3422 °C is the highest of all metals and second only to carbon's, for which melting occurs only at high pressure (there's no standard melting point). This is why tungsten ...
• 81.6k

### How do you melt metals with super high melting points?

Sorry, can't comment here, but I wanted to more directly answer your question. Blacksmiths avoid melting their forges because the "heat" that can melt or oxidize iron and steel is actually ...
• 601
Accepted

### Why is the melting point of PCl3 less than that of PCl5?

Because $\ce{PCl5}$ does something which is not immediately obvious from its molecular formula: it autoionizes and becomes an ionic solid $\ce{PCl4+PCl6-}$. As such, it has much stronger interactions ...
• 29.6k

### What easily accessible material has melting point between 500 °C and 590 °C?

Temperature-indicating or thermo crayons are used by welders. These melt at specific temperatures. Not as an endorsement, but to give you an idea of what's available, the crayons from McMaster-Carr ...
• 391
Accepted

### What happens if you cool water in a container too small for it to freeze?

Good question. Let's assume the container is infinitely strong, non-deformable, and constant in volume. Let's also assume that cooling the water is an equilibrium process -- that way, we won't have ...
• 20.2k

### How do you melt metals with super high melting points?

We use an levitating furnace to heat samples of refractory ceramics up to approx $3000~^\circ\mathrm{C}$. Its for research purposes, so the samples are small (2 mm) beads. These are balanced on a jet ...

### Is honey really a supersaturated solution? Does heating to un-crystalize redissolve it or melt it?

Honey is indeed a complex mixture containing more than hundred compounds. As for Wikipedia and depending on the point of view it is a supersatured liquid solution a viscous supercooled liquid (in ...
• 3,534
Accepted

### Melting point of aspirin, contradicting sources

Wolfram company doesn't conduct any experimental determinations of physical constants for chemical compounds and uses literature data sources. The webpage for ChemicalData Source Information lists ...
• 34.7k

### Why do the melting and boiling points of the noble gases increase when the atomic number increases?

The melting and boiling points of noble gases are very low in comparison to those of other substances of comparable atomic and molecular masses. This indicates that only weak van der Waals forces or ...
• 2,228
Accepted

### Boiling and melting point of trans- and cis-but-2-ene

Yes . You are right that structural symmetry comes into play . Boiling point depends upon intermolecular interactions which over here is more in cis due to its net dipole moment . The dipole ...
• 2,107

### Is honey really a supersaturated solution? Does heating to un-crystalize redissolve it or melt it?

Melting and dissolving are all the same when you look at mixtures close to saturation. You can say water lowers the melting point of the sugar, or that the solubility of sugar increases with ...
• 11.4k

### Which substance has the highest temperature range between melting and boiling point

Gallium melts at 30 °C but doesn't boil until 2200 °C. If 30 °C is a bit too warm to count as "room temperature" or "normally" for you, I found an old paper that recommends tetralkyl ...
• 20.2k

### What easily accessible material has melting point between 500 °C and 590 °C?

It might not qualify as 'available at home' but MakeItFrom has a database with engineering material you can search: MakeItFrom.com is a curated database of engineering material properties that ...
• 2,039
Accepted

### How to RAISE the melting point of water?

source One way to raise the melting point of water is to increase pressure beyond about 635 MPa. By raising pressure you could get the melting point to be even greater than the normal boiling point. ...
• 38.8k

### How can steel be so different from iron, even if amount of carbon is small?

One of the key considerations is that much of the interesting mechanical behaviour doesn't occur within the bulk of the material - it occurs at the interfaces between crystals (known as grains). Grain ...
Accepted

### How to calculate melting/boiling points at different pressures?

I don't believe there is an equation that you can use for melting points of a general substance as a function of pressure (since the melting phase transition has a lot to do with the geometry of the ...
• 10k

### Melting point of obsidian

Obsidian This is a volcanic glass, formed when rhyolitic lavas cool too quickly for crystals to form. From a chemistry point of view, it's a mixture of silicon dioxide, aluminium oxide, with sodium ,...

### How do you melt metals with super high melting points?

One could melt them floating on a pool of high-boiling point denser metal, or in space where they can readily be contained. Or one could create a thick actively cooled shell and melt them inside it, ...
• 121
Accepted

### How to calculate which ionic compound has the highest melting point?

The strength of the ionic bond depends on Coulomb's law for the force acting between two charged particles where larger force translates to a stronger ionic bond. The equation is F = \frac{-k\cdot ...
• 3,343
Accepted

### Which substance has the highest temperature range between melting and boiling point

The polar aprotic solvents (for example dimethylformamide, mp −61 °C, bp 153 °C, or hexamethylphosphoramide, mp 7 °C, bp 230–232 °C) would be a place to start. Silicone oil is often used in heating ...
• 9,006

### How do you melt metals with super high melting points?

There are two alternatives to the other answers here, though whether they can be used on a large scale is open to question. The first is to use an actively cooled vessel to hold the metal and a ...
• 32k
Accepted

### Will heating alumina (Al2O3) to its melting point yield pure Al?

You've figured out one half of the Hall-Heroult process. Just melting alumina on its own won't liberate the oxygen. The reason is difficult to explain without getting into chemical thermodynamics - ...
• 10k
Accepted

### At what temperature (in kelvin) are most of the elements on the periodic table liquids?

Now that's a great question indeed! Evidently, at 0K all elements except helium are solids, at 10000K they are all gases, so someplace in between the number of liquids must reach a maximum; what and ...
• 29.6k
Accepted

### How to separate alloys?

You seem to approach the separation of alloys much like the separation of water-soluble salts, probably based on the fact that both involve the liquid/solid phase diagrams, which may even look alike. ...
• 29.6k
Accepted

### Predicting melting points of substances based on their molecular/atomic structure

Melting point depends not only on the structure of the molecule itself, but also on the structure of the solid (crystalline) phase and molten/liquid state of the substance. That is a much bigger ...
• 9,006

### Are there compounds that melt under their own weight?

Sure. Even discounting non-equilibrium conditions, any substance which expands upon freezing will by symmetry melt under pressure, even if the pressure is caused by supporting its own weight. There's ...
• 26.2k

### The effect of air pressure on the melting point

For most substances, higher pressure (or air pressure, in your case) will cause the melting temperature to go up. To think about it intuitively, imagine that you have a certain solid. Melting it would ...
• 4,924
In stereochemical vocabulary, a racemic mixture (racemate) is one that has equal amounts (50:50) of left- and right-handed ($d$- and $l$-) enantiomers of a chiral molecule. According to Wikipedia: ...
Name Formula m.p./°C Copper(II) chloride $\ce{CuCl2}$ 498 Barium perchlorate $\ce{Ba(ClO4)2}$ 505 Potassium fluoroborate* $\ce{KBF4}$ 530 Antimony trisulfide (stibnite) $\ce{Sb2S3}$ 550 Calcium ...