– and looking at well after well under a microscope to look for the crisp edges of crystals but mostly seeing gunky stuff)īut anyways, back to coal…Its “random” carbon packing makes it easy to incorporate impurities because the carbons don’t have to fit into a carefully “calculated” repeating structure. So we spend a lot of time trying to find the right conditions for crystallization – testing out a bunch of different “cocktails” of different salts, etc. Instead it’s an AMORPHOUS SOLID (no defined shape) – instead of following a floor plan, the C atoms in coal stick together more “willy-nilly” (protein crystallographers know all too well the difference between a crystal and an amorphous clump of protein gunk! The technique of x-ray crystallography for determining protein structure relies on protein molecules organizing in a perfectly-repeating pattern, so that, when we beam x-rays at them, those rays bounce off the atoms of each copy the same way & their signals add up – so we can capture the reflected rays on a detector and work backwards to figure out the protein structure. COAL *is* a solid form of C, BUT it is NOT crystalline. 3 of the main carbon crystal allotropes are DIAMOND, GRAPHITE, & FULLERENES. The same element can have multiple such floor plans leading to crystals w/different properties – we call these different arrangements ALLOTROPES & carbon (C) has multiple.
In a CRYSTALLINE solid, the place they’re stuck in follows a repeating floor plan (think of a brick wall or a tiled floor in 3D). And in a SOLID, atoms are stuck in place & only have enough energy to vibrate. The basic unit of all these elements is an atom. But turns out carbon can be pretty cool all by itself. We’ve talked a lot about hydrocarbons – carbon hooked up to hydrogens – and how they make great skeletons for “organic” biochemical molecules like proteins & DNA, which are based on hydrocarbons with some other elements, like oxygen and nitrogen, sprinkled in as parts of “functional groups” in place of hydrogen. But I did get another “allotrope” of carbon – graphite (Snoopy pencils ? ) What’s the difference – all aboard the CARBON ALLOTROPE Express to find out! – yet they’d probably love to see the same element, carbon in a different arrangement – because diamonds and coal are the made up of the same thing! I didn’t get coal in my stocking. This Christmas morning, millions around the world looked in their stockings & hoped not to see coal.