Amorphous carbonia, also called a-carbonia or a-CO₂, is an exotic

amorphous In condensed matter physics and materials science, an amorphous solid (or non-crystalline solid) is a solid that lacks the long-range order that is a characteristic of a crystal. The terms "glass" and "glassy solid" are sometimes used synonymousl ...

solid form of

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

that is analogous to amorphous silica glass. It was first made in the laboratory in 2006 by subjecting

dry ice Dry ice is the solid form of carbon dioxide. It is commonly used for temporary refrigeration as CO2 does not have a liquid state at normal atmospheric pressure and Sublimation (phase transition), sublimes directly from the solid state to the gas ...

to high pressures (40-48 gigapascal, or 400,000 to 480,000

atmosphere An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...

s), in a

diamond anvil cell A diamond anvil cell (DAC) is a high-pressure device used in geology, engineering, and materials science experiments. It permits the compression of a small (sub- millimeter-sized) piece of material to extreme pressures, typically up to around 1 ...

. Amorphous carbonia is not stable at ordinary pressures—it quickly reverts to normal CO₂. While normally carbon dioxide forms molecular crystals, where individual molecules are bound by

Van der Waals force In molecular physics and chemistry, the van der Waals force (sometimes van der Waals' force) is a distance-dependent interaction between atoms or molecules. Unlike ionic or covalent bonds, these attractions do not result from a chemical elec ...

s, in amorphous carbonia a covalently bound three-dimensional network of atoms is formed, in a structure analogous to

silicon dioxide Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundan ...

or germanium dioxide glass. Mixtures of a-carbonia and a-

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant f ...

may be a prospective very hard and stiff glass material stable at room temperature. Such glass may serve as protective coatings, e.g. in

microelectronics Microelectronics is a subfield of electronics. As the name suggests, microelectronics relates to the study and manufacture (or microfabrication) of very small electronic designs and components. Usually, but not always, this means micrometre ...

. The discovery has implications for

astrophysics Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, astrophysics "seeks to ascertain the ...

, as interiors of massive planets may contain amorphous solid carbon dioxide.

Notes

References

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External links

Dry ice creates toughened glass

Physicsweb: Dry ice forms ultrahard glass
Carbon dioxide Amorphous solids Physical chemistry Astrophysics Glass compositions {{astrophysics-stub