Can diamond react to form graphite? Under what conditions?

Yes, c(s, diamond) ===c(s, graphite) h<0 The reaction is reversible, and the reaction conditions are high temperature and high pressure catalysts. In other words, graphite and diamond can be converted into each other under the same conditions.

There is a way to oxidize after re-reduction estimated possible.

But graphite can react into diamond at high pressures.

Refer to this.

c (diamond) = c (graphite); △h =

Graphite is more stable than diamond, and this reaction is exothermic. However, there is generally no such transformation, and they all want to use graphite to make diamonds (diamonds).

In 2004, there was such a question in the National Science and Technology Comprehensive:

It is known that at 25 and 101 kPa, the thermochemical equations of graphite and diamond combustion are c(graphite) +O2(g) = CO2(g); H = C(Diamond) +O2(G) = CO2(G); h= From this, the following statement is correct.

a Preparation of diamond from graphite is an endothermic reaction; At the same mass, the energy of graphite is lower than that of diamondb The preparation of diamond from graphite is an endothermic reaction; At the same mass, the energy of graphite is higher than that of diamondc The preparation of diamond from graphite is an exothermic reaction; At the same mass, the energy of graphite is lower than that of diamond d The preparation of diamond from graphite is an exothermic reaction; At equal mass, the energy of graphite is higher than that of diamond, and the answer is a

No, they are all the same substance, but the arrangement of atoms is different and cannot be changed.

Theoretically, yes, because graphite can turn into diamond.

But who's going to do it?

Which is more valuable, no one burns money so much, right?

When a standard pressure (or atmosphere) greater than 15,000 is applied to the surface of graphite, graphite can be converted into diamond. Want diamond to graphite? Waste!

It has to do with the internal arrangement of atoms, and any chemical change is essentially the process by which atoms recombine to form molecules and then form matter

However, it is still possible to react through nuclear fission

Yes, just heat it up! But it doesn't count.

Theoretically, it is possible, but the reaction conditions are unknown.

The conversion of graphite to diamond is a chemical change.

But it is not because of the change in molecular structure, neither graphite nor diamond has a molecular structure because they are atomic crystals. The transformation of graphite into diamond is a change in the crystal structure, and there is a break and formation of chemical bonds, so it is a chemical change.

Graphite is a single laminated layer, the atoms are honeycomb-like arrangement, the spacing is small, the binding force is strong, but the distance between the pieces is very long, and the binding force is weak, so that the graphite as a whole is very soft. The atoms are spaced in nanometers, while the interlayers are nanometers.

The carbon atoms in diamond are arranged in a tetrahedral manner, with the same distance between the atoms in each direction, and they are all nanometers. Therefore, the hardness of diamond is much greater macroscopically, because its atomic spacing is smaller than that between graphite layers. However, it is inferior to graphite in terms of high temperature resistance, because its atomic spacing is larger than that of graphite.

The interconversion of diamond and graphite under certain conditions is a chemical change. Because the two are allotropic forms, all the mutual changes of allotropic forms under certain conditions are chemical changes.

In the crystal, the carbon atoms in the same layer are hybridized by sp2 to form a covalent bond, each carbon atom is associated with three other carbon atoms, and the six carbon atoms form a regular hexagonal ring in the same plane, which stretches to form a lamellar structure.

The carbon atoms in the same plane each have a p orbital left, and they overlap each other to form a delocalized bond electrons that can move freely in the crystal lattice and can be excited, so graphite has a metallic luster, can conduct electricity and transfer heat. Due to the large distance between the layers, the small binding force (van der Waals force), and the fact that each layer can slide, the density of graphite is smaller than that of diamond, and the texture is soft and smooth.

Graphite belongs to the hexagonal crystal system with complete layered cleavage. The cleavage plane is dominated by molecular bonds, and the attraction to molecules is weak, so its natural floatability is very good.

Diamond and graphite can be transformed under certain conditions, is this transformation a physical change or a chemical change? We can analyze this problem from the following aspects.

1 Characteristics of chemical change.

We know that chemical changes are often referred to as chemical reactions. A chemical change is a change in which other substances are produced when the change occurs. Substances are transformed into new substances that are completely different in nature through chemical reactions, which is the characteristic of chemical change.

When graphite, an element composed of carbon, becomes a diamond under certain conditions, although diamond is also a carbon element, the properties of diamond are very different from graphite (the chemical properties of graphite are more active than diamond); It is another elemental element of carbon. This shows that diamond is a new substance that is changed from graphite in the process of change. If there is a change in the formation of new matter, it is not a physical change.

2 Crystal structure.

When graphite is converted to diamond, the graphite crystal structure is destroyed; The weak bond between the middle layer of graphite and the layer is broken or changed, or at the same time, the chemical bonds and bonding methods between the carbon atoms on the hexagonal plane are "greatly changed and reorganized", so that the combination between them is regularly combined into a three-dimensional centric structure according to the form and requirements of diamond. That is, the layered structure of graphite is transformed into a regular tetrahedral structure of diamond. Based on the fact that there is only one structure of the same substance, graphite and diamond are two substances with different crystal structures.

Since the process of change is from one substance to another, it is not a physical change. It can be seen that the transformation of matter from one structure to another is a chemical change process.

3 Thermal effects.

When a chemical reaction is carried out, it is often accompanied by a change in energy, which can be in the form of light, electricity, mechanical or thermal energy, and often in the form of thermal energy, sometimes to release heat, sometimes to absorb heat. Diamond is heated to 1000 °C in isolation from air and can be converted into graphite

This transition is an exothermic reaction. It illustrates the conversion of energy into the form of heat when a chemical reaction occurs during this transition. When graphite becomes diamond, it is a chemical reaction that absorbs heat energy. Therefore, the transformation of graphite into diamond under certain conditions is not a physical change.

4 Catalysts.

The conversion of graphite into diamond must be carried out at high temperature and high pressure, and even at a temperature of 2000 4000 and a pressure of 6120,000 atmospheres, this conversion rate is still not large, and chromium, iron and platinum are used as catalysts. According to the principle that a catalyst can only change the rate of chemical reactions, a catalyst cannot change the rate of physical change. When graphite is converted to diamond, a catalyst is used to speed up the reaction rate.

If this transition is physical, wouldn't the use of catalysts be meaningless? It can be seen that this transition is not a physical change.

In summary, the interconversion of diamond and graphite under certain conditions is a chemical change. All interchanges of allotropes under certain conditions are chemical changes. Some people say that the mutual conversion of diamond and graphite under certain conditions is a physical change process, but this statement is incorrect.

The main component of graphite is carbon, the main component of diamond is also carbon, graphite and diamond are two different substances, graphite is the main raw material of pencil lead, diamond can be made of diamond, so although both are composed of the same element, but the spatial structure is different, so it is different substances, so graphite to diamond is a new substance generated, so it is a chemical change. Distinguish between physical and chemical changes.

Physical change is a change in the shape, size, density, shape, charge charge, temperature and other aspects of the object, such as ice breaking, water evaporation, etc. Its essence is that the smallest particle itself that maintains the chemical properties of the substance does not change, but the spacer motion between the particles changes.

A chemical change is a chemical reaction. A chemical change is a change in which other substances are produced when the change occurs. Substances are transformed into completely different in nature through chemical reactions'New substances, this is the characteristic of chemical change, chemical change is often accompanied by luminescence, heat, color change, gas production, precipitation and other phenomena, which can help determine whether it is a chemical change.

Microscopically speaking, it is the process in which the molecules that make up an object are destroyed into a single atom, and the atoms are reconstituted into new molecules, which is characterized by the formation of new substances. Such as the rust of iron, the fireworks of festivals, the neutralization of acid and alkali, the burning of magnesium strips, and so on. Chemical changes are accompanied not only by the formation of new matter, but also by changes in energy, which are usually manifested in the release or absorption of heat, light, and electrical energy.

Physical change must occur during chemical change, but chemical change does not necessarily occur during physical change.

1. The conversion of graphite into diamond is a chemical change.

2. The combination of chemical bonds between graphite and diamond is different for two types of substances with different structures. Transitions between each other must involve the breaking and formation of chemical bonds.

3. Graphite is a "transitional crystal" with a "layered structure": the carbon atoms in the layer are combined by covalent bonds to form a regular hexagonal network structure, and the distance between the layers is large, which is equivalent to the action of intermolecular forces; Diamond is the hardest substance and cannot conduct electricity, while graphite has less hardness, can slide relatively between layers, has good conductivity, and is more chemically active than diamond.

The essence of chemical change is the destruction of the original chemical bond and the formation of new chemical bonds.

We know that diamond is an "atomic crystal" formed by the covalent bond of carbon atoms with a positive "four-sided friendly space network structure", and graphite is a "transitional crystal" with a "layered structure" Li Zao: the carbon atoms in the layer are combined by covalent bonds to form a regular hexagonal network structure, and the distance between the layers is large, which is equivalent to the action of the intermolecular force; Diamond is the hardest substance and cannot conduct electricity, while graphite has less hardness, can slide relatively between layers, has good conductivity, and is more chemically active than diamond. Obviously, graphite and diamond are two different types of substances with different structures, and the bonding of chemical bonds is different.

Transitions between each other must involve the breaking and formation of chemical bonds.

So it is safe to say that the conversion of graphite to diamond is a chemical change!

In fact, any change between allotropes, such as red and white phosphorus, oxygen and ozone, is a chemical change.

Xinruida graphite answers for you, and wishes you a prosperous business.