[jadelamlam]

Hi,
there are 2 pictures in the attached,pic 2 shows a diamond in rectangular shape.
pic 1 shows the 3D structure of that diamond at a corner of it.
As we know,diamond has a giant covalent structure,which means atoms in it are linked together by covalent bonds only.
Now,please see the pink circle,3 electrons of that carbon atom are covalently bonded to 3 other carbon atoms.
Each carbon atom has 4 outermost electrons.Where is the remaining electron?

Is it forming a covalent bond with another element?(e.g.oxygen in the air)
If not,it should be reactive due to the unbonded electron but in fact diamond is unreactive.
From the above deduction,there is no diamond with 100% purity(i.e.no impurities)?

just a guess

Please help,thx

[Arkcon]

From the above deduction,there is no diamond with 100% purity(i.e.no impurities)?

I used to wonder this exact question, and you have hit upon the correct answer.  All crystalline materials contain some inclusions that average out so that the crystal can have an end.  I tried to corner material scientists with a "but what if it were perfect," but there is no answer except that simply doesn't happen.