Smell
the further one moves down the periods, the melting point decreases. since sillicon is placed before chlorine, chlorine has lower melting point.
The addition of water can lower partial melting temperatures in silicate rocks.
Sulfur melts at a much lower temperature than sand. That might be useful. Also, there are solvents which will dissolve sulfur but not silicon dioxide. Finally, there's always the magnifying glass and tweezers method.
LOWER
The melting point of salt water is even lower than pure water.
Glass is a mixture, not only silicon dioxide.
Silica = silicon dioxide = SiO2 is the only ingredient of quartz glass, often sodium and calcium oxides are added to lower the melting point. Often sodium carbonate and calcium carbonate are used as the metal oxide source and the carbon dioxide escapes into our atmosphere during the melting.
You Ultimately would not expect them to have similar melting and boiling points.This is because Carbon Dioxide is a gas, it might have strong covalent bonds between their atoms but between their molecules they have weak intermolecular forces, therefore these forces are easily overcome during heating in lower temperaturesHowever when you look at Silicon Dioxide, it has a macromolecular structure. In other words the whole solid is actually just one molecule which its atoms are each covalently bonded to each other. Therefore since it has strong covalent bonds between them you would expect them to have extremely high melting and boiling points.Diamond is a macromolecular structure and it has a melting point of 3006 degrees centigrade. You could expect Silicon Dioxide's melting point (and boiling point) to be similarly high.
The bond energy of Si -C is generally considered to be lower than that of the C-C, so a simple explanation is that diamond has a stronger bond. Both diamond and silicon carbide have a three dimensional network structure. Diamond consists of tetrahedral bonded carbon atoms whereas silicon carbide has many polymorphs (crystal structure which are temperature dependant). As you heat silicon carbide up the crystal structure changes. Silicon carbide does not melt "congruently" to give a liquid of the same composition, it decomposes at around 2700 0C .
non-metals have lower density, melting and boiling point but diamond has higher density, melting and boiling point.
Molecular covalent compounds have lower melting points because the inetrmolecular forces are weaker than ionic bonds. Note that giant covalent structures, such as silicon dioxide, can have very high melting points, the key factor is not simply the nature of the bond.
the further one moves down the periods, the melting point decreases. since sillicon is placed before chlorine, chlorine has lower melting point.
Since diamond has the highest melting point of any mineral, unless you can produce 3820 degrees Kelvin -- 6,416.6º F or 3,547º C, lower temperatures will not affect a diamond.
No they have high melting and boiling points. Don't get confused with simple molecular structures such as water and carbon dioxide which have simple covalent structures. When you heat them you are overcoming the forces BETWEEN THE MOLECULES (intermolecular/van der waals forces of attraction), NOT the actual covalent bonds themselves, like the bond betwen the C and either O in carbon dioxide.
If my math is correct, you're asking for the melting point at a distance of about six miles above sea level -- which means you're probably air-born. The melting point of diamond is 3,820 Kelvin. So assuming you have the gear that can produce that temperature at that altitude, you could melt a diamond. Given the altitude, the Kelvin reading might be a little lower.
Normally, glass contains SiO2 (sand or silicon dioxide), lime, and soda, added to give it a lower melting point. For precise lab work, where these would contaminate the results, then pure silica glass is used. The addition of boron gives the glass a lower coefficient of expansion, and this gives us such things as Pyrex, glass topped stoves, etc.
lower melting points