Search results
Results from the WOW.Com Content Network
In chemistry a donor number (DN) is a quantitative measure of Lewis basicity.A donor number is defined as the negative enthalpy value for the 1:1 adduct formation between a Lewis base and the standard Lewis acid SbCl 5 (antimony pentachloride), in dilute solution in the noncoordinating solvent 1,2-dichloroethane with a zero DN.
This is a list of scientific journals in chemistry and its various subfields. For journals mainly about materials science, see List of materials science journals. A
In crystallography, a vacancy is a type of point defect in a crystal where an atom is missing from one of the lattice sites. [2] Crystals inherently possess imperfections, sometimes referred to as crystallographic defects. Vacancies occur naturally in all crystalline materials.
The effective atomic number for electron interactions may be calculated with a similar approach. [ 5 ] [ 6 ] The cross-section based approach for determining Z eff is obviously much more complicated than the simple power-law approach described above, and this is why freely-available software has been developed for such calculations.
The CAS Chemical Registry System was introduced in 1965. CAS developed a unique registry number to identify chemical substances. Agencies such as the U.S. Environmental Protection Agency and local fire departments around the world now rely on these numbers for the definite identification of substances. According to the ACS, this is the largest ...
The quantum defect may also be defined as follows: at a given frequency of pump and given frequency of lasing, the quantum defect = /; according to this definition, quantum defect is dimensionless. [ citation needed ] At a fixed pump frequency, the higher the quantum defect, the lower is the upper bound for the power efficiency.
If the group is of the [ns, np] type, an amount of 0.85 from each electron with principal quantum number (n–1), and an amount of 1.00 for each electron with principal quantum number (n–2) or less. If the group is of the [d] or [f], type, an amount of 1.00 for each electron "closer" to the nucleus than the group.
A defect can be defined as a nonconformance of a quality characteristic (e.g. strength, width, response time) to its specification. DPMO is stated in opportunities per million units for convenience: processes that are considered highly capable (e.g., processes of Six Sigma quality) are those that experience fewer than 3.4 defects per million ...