Why is graphite to diamond not spontaneous?

Diamond is thermodynamically unstable because delta G for diamond to graphite is negative and therefore spontaneous, but the transition from diamond to graphite has a large activation energy barrier, so diamond is not likely to transition on its own to graphite and is therefore kinetically stable.

Is conversion of graphite to diamond spontaneous?

Thermodynamic Stability

From the phase diagram of carbon, it can be seen that diamond is the thermodynamically favored allotrope under geological conditions of high pressure, but at ambient conditions, graphite is the more stable allotrope, and diamond spontaneously converts to graphite. … Figure18.1.

Why does the exothermic reaction diamond to graphite not occur spontaneously?

When it happens, this is an explosive process because so much energy is released BUT IT IS NOT SPONTANEOUS because, initially, at room temperature there is not enough energy to break the H-H and O=O. bonds for the reaction to get started.

Is diamond graphite spontaneous at room temperature?

At room temperature, conversion of diamond into graphite is spontaneous.

What kind of reaction is diamond to graphite?

The conversion of diamond into graphite is an endothermic reaction.

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Why is diamond not thermodynamically unstable?

Diamond has a rigid and compact structure due to which it takes more energy and time to convert into graphite and therefore, it is kinetically more stable but thermodynamically less stable than graphite.

Why diamond is metastable?

Diamond and Graphite

Diamond is composed of the single element carbon, and it is the arrangement of the C atoms in the lattice that give diamond its amazing properties. … So diamond is said to be metastable, since it is kinetically stable, not thermodynamically stable.

Is diamond to graphite endothermic?

The conversion of diamond into graphite is an endothermic reaction.

Why does the exothermic reaction not occur spontaneously?

Since the energy of the system decreases during an exothermic reaction, the products of the system are more stable than the reactants. … Therefore, the reaction would not occur without some outside influence such as persistent heating. However, endothermic reactions do occur spontaneously, or naturally.

Why do high pressures favor the formation of diamond from graphite?

Graphite is heated to 1500 °C and compressed to a pressure of 15 million kPa, graphite becomes DIAMOND. This happens because this HPHT (High Pressure, High Temp) method breaks the hexagonal C rings in graphite and rebuilds it into 3D diamonds. This is also the reason why Diamonds cannot become Graphite.