Elemental-ry?

Question

i am having problems finding appearance details about the element carbon. i really need this! i cant seem to find anything about its appearance except that when it creates carbon it is black and when it is diamond it is colorless! so, if i were to have a pure sample of carbon, what would be some characteristics i could notice??


thanks!

Answer 1

Diamond and graphite are both separately pure forms of carbon. In chemistry, we'd call them allotropes, different structural forms of the same element. They just exhibit different types of bonding. Diamond crystalizes in a cubic structure named for it (diamond cubic) and has what's called sp3 bond hybridization. In simple language, sp3 means each carbon bonds with 4 other things in a tetrahedral (equilateral triangle pyramids) structure, that's why it's so strong. Graphite crystallizes in sheets of hexagons layered on top of each other, in sp2. This makes each carbon in graphite bonded to 3 others, and its structure is flat, which makes it into sheets, and the layered sheets explain why it's soft.

Diamond is transparent if its uniform, and has no impurities (ex: small N impurity would make it yellowish) and it has a band gap (an electrical property stating how much energy must be put into a material to make an electron able to transfer current (conduct)) with an energy value greater than that of the energy you would get from visible light (visible light can't excite the electrons to conduction, so it passes through the material, and you see all colors of visible light through it, so it's transparent).

Graphite appears black-grayish because it's band gap value is just slightly lower than visible light energy, its close to 0, so it absorbs all visible light and you see dark color. Graphite is more conductive electrically than diamond for that reason, and its shiny black-gray appearance follows with that.

Most pure carbon you'll see is graphite, hence why diamonds are so expensive. Most graphite you'll find is disordered, so it has mostly its normal bonding and a small amount of disorder, however it still appears grayish.

Answer 2

There really is no good answer to this. Pure carbon can come in three different forms and they all look different. Coal/graphite is black and soft, while diamond is colorless and hard. I have no idea what buckminsterfullerenes, the third type, look like. None of these is any more "pure" carbon than the others.

Answer 3

Graphite and diamond are both pure carbon. They are called 'allotropes' of carbon, which basically means that they have different atomic arrangments, but the same chemical composition. In diamond, the carbon atoms are arranged in a tightly-packed tetrahedral crystal. In graphite, the carbon atoms form two-dimension sheets with the bonds arranged in a hexagonal manner. The different crystal structures of these allotropes leads to great diffences in physical properties (like color, hardness, tensile strength, etc.).

In addition to graphite and diamond, carbon has other, less common allotropes such as fullerenes and carbon nanotubes.

Other elements also have different allotropes. Phosphorus can exist as red or white phosphorus. Oxygen can exist as diatomic O2 (most common), or as ozone, O3.

Answer 4

Well Carbon comes in two basic solid forms. Diamond and Graphite.

Diamond has a hard crystalline structure with each carbon bonding to four others in a tight network and as you noted it is colorless (colored diamonds are due to impurities in the crystal matrices).

Graphite on the other hand forms in sheets and is soft and slippery and dark to light silvery Grey in color. It is one of the softer substances in contrast to diamond which is one of the hardest.

Answer 5

I dont get it