An isotopical pure diamond is a type of

diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, ...

that is composed entirely of one

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

. Isotopically pure diamonds have been

manufactured Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of secondary sector of the economy. The term may refer to a ran ...

from either the more common carbon isotope with

mass number The mass number (symbol ''A'', from the German word ''Atomgewicht'' tomic weight, also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. It is approxima ...

12 (abbreviated as ¹²C) or the less common ¹³C isotope. Compared to natural diamonds that are composed of a mixture of ¹²C and ¹³C isotopes, isotopically pure diamonds possess improved characteristics such as increased

thermal conductivity The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by k, \lambda, or \kappa. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal ...

. Thermal conductivity of diamonds is at a minimum when ¹²C and ¹³C are in a ratio of 1:1 and reaches a maximum when the composition is 100% ¹²C or 100% ¹³C.

Manufacture

The isotopes of carbon can be separated in the form of

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

gas by cascaded chemical exchange reactions with amine carbamate. Such CO₂ can be converted to methane and from there to isotopically pure

synthetic diamond Lab-grown diamond (LGD; also called laboratory-grown, laboratory-created, man-made, artisan-created, artificial, synthetic, or cultured diamond) is diamond that is produced in a controlled technological process (in contrast to naturally formed ...

s. Isotopically enriched diamonds have been synthesized by application of chemical vapor deposition followed by

high pressure In science and engineering the study of high pressure examines its effects on materials and the design and construction of devices, such as a diamond anvil cell, which can create high pressure. By ''high pressure'' is usually meant pressures of th ...

Types

Carbon 12

The ¹²C isotopically pure, (or in practice 15-fold enrichment of isotopic number, 12 over 13 for carbon) diamond gives a 50% higher

than the already high value of 900-2000 W/(m· K) for a normal diamond, which contains the natural isotopic mixture of 98.9% ¹²C and 1.1% ¹³C. This is useful for heat sinks for the

semiconductor A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way. ...

industry.

Carbon 13

Isotopically pure ¹³C diamond layers 20 micrometers thick are used as stress sensors due to the advantageous Raman spectroscopy properties of ¹³C.

References

{{reflist Synthetic diamond Isotopes of carbon