Why is Diamond transparent but graphite black ?

Answer 1

Very simple. What makes any material colored the way it is, is due to electrons and what they are doing within.

Diamond is made of carbons bonded to each other only by sigma covalent bonds. All of the electrons in diamond are occupied in these Carbon-Carbon covalent bonds, which absorb only IR light, making them transparent to our vision.

Graphite is made up of sheets of conjugated aromatic benzene rings. If you consider the structures of dye molecules, you will see that the more conjugated a dye molecule is, the higher the extinction coefficient. Graphite is in effect the ultimate conjugated organic system; it has unlimited pi electrons to absorb light. By the way, all these pi electrons are the reason graphite is an excellent conductor of electricity.

Answer 2

Diamonds are unstable compared to coal (or more exactly, graphite) so high
temperature and pressure are required for diamonds to form from graphite.
The reason that coal (graphite) is black and diamonds are clear has to do
with how the carbon atoms are connected together in the two different forms
of carbon. In diamond each carbon atom is bonded to its neighbors like the
points of a pyramid. In graphite (coal) the atoms are connected to one
another is flat planes. The flat planes can absorb light of all wavelengths
(colors) while the pyramids found in diamonds cannot absorb any visible
light and as a result are transparent. The reason for the difference is that
the electrons in the large flat sheets of graphite can all "giggle" at many
frequencies, but the tightly bound and constrained electrons in diamond are
not free to "giggle" and thus cannot absorb light.
Heat and pressure change coal into diamond, but it is the change in crystal
structure that results in the color change. Graphite is composed of flat
sheets of carbon similar to shale and basically keeps going in all direction
until the end of the sheet. Diamond is a 7-carbon crystal, which is
3-dimentional and therefore gives the crystal light refracting properites.
Color is a result of light absorbtion or light reflextion. Black means
that all possible colors are being absorbed and white means that all colors
are reflected. In the case of diamond, it is clear because light passes
through it. The brilliance of diamond comes from internal refraction, then
the light separating out into each individial color, like a prism. The
diamond is cut in such a way so that the light enters the top, gets
partially reflected off of the bottom cuts and comes back out the top as a
rainbow. The better the cut and clarity of the diamond, the more
brilliance/sparkle you obtain.

Answer 3

In the 3 dimentiional Lattice-in diamond the carbon atoms are all perfectly arranged at the interjunctins of the lattice.When light enters from a rarer medium to a denser medium there is a small amount of Refraction/Difrraction and Total Internal Reflection.Depending on the quantam of difraction the colours Blue to Red (VIBGYOR) are reflected(play of colours what they call "Fire").In Graphite the arrangement of carbon atoms are erratic in the lattice.So all light is absorbed and nothing is reflected-so Black in colour(no white light nor colour comes out of that)...

Answer 4

Because the atoms and covalent bonds in diamond are loosely packed when compared to graphite.That space between atoms which is very high makes us feel the transparency of diamond and which is not the case with graphite.

Answer 5

The answer is simple that the structure of diamond allows light to pass thru it but not graphite
as diamond molecule has a wide gap in it's structure
* this is what I think;
but in case of graphite due to layered structure it may not allow light to pass thru it

Answer 6

Diamonds are transparent and graphite are black although they are allotropes of carbon 'coz their physical properties are different.Since they r allotropes their chemical properteis r same.

Answer 7

Actually many diamonds (used as industrial abrasives) are not transparent.

Answer 8

Reason= the difference in there structure and bonds between the carbon atoms!

Answer 9

shreya this question is a typical question in ninth standard (CBSE)chemistry.take a look at some book by manjeeth singh or so.you ll find the answer.just in case you dont, it is because of the structure.