CHEMISTRY GLOSSARY
beryllium → berilij
Beryllium was discovered by Friedrich Wöhler (Germany) and independently by A. B. Bussy (France) in 1828. The origin of the name comes from the Greek word beryllos meaning mineral beryl; also called glucinium from the Greek word glykys meaning sweet. It is steel-grey metal. It resists attack by concentrated nitric acid, has excellent thermal conductivity and is nonmagnetic. At ordinary temperatures, it resists oxidation in air. Beryllium and its salts are toxic and should be handled with the greatest of care. Beryllium is found mostly in minerals like beryl [AlBe3(Si6O18)] and chrysoberyl (Al2BeO4). Pure beryllium is obtained by chemically reducing beryl mineral. Also by electrolysis of beryllium chloride. Its ability to absorb large amounts of heat makes it useful in spacecraft, missiles, aircraft, etc. Emeralds are beryl crystals with chromium traces giving them their green colour.
body-centered cubic lattice → prostorno centrirana kubična rešetka
Body-centered cubic lattice (bcc or cubic-I), like all lattices, has lattice points at the eight corners of the unit cell plus an additional points at the center of the cell. It has unit cell vectors a = b = c and interaxial angles α=β=γ=90°.
The simplest crystal structures are those in which there is only a single atom at each lattice point. In the bcc structures the spheres fill 68 % of the volume. The number of atoms in a unit cell is two (8 × 1/8 + 1 = 2). There are 23 metals that have the bcc lattice.
enthalpy growth → prirast entalpije
Enthalpy growth (ΔH) is that part of energy of system which can be translated into heat (Q) with a permanent pressure.
environment → okolina
Environment (in thermodynamics) is the whole universe, except the system that is being observed.
equation of state → jednadžba stanja
Equation of state is an equation relating the pressure, volume, and temperature of a substance or system. Equation of state for ideal gas
where p is pressure, V molar volume, T temperature, and R the molar gas constant (8.314 JK-1mol-1).
fraction → udio
Fraction is a ratio of two quantities of the same kind, the numerator quantity applying to one constituent (or part) of the system and the denominator to the sum of quantities for all constituents (parts) of the system. When applied to mixtures fractions represent a group of three quantities: mass fraction, volume fraction and amount fraction (or mole fraction equal to the number fraction).
Born-Haber cycle → Born-Haberov kružni proces
Born-Haber cycle is a cycle of reactions used for calculating the lattice energies of ionic crystalline solids. For a compound MX, the lattice energy is the enthalpy of the reaction
The standard enthalpy of formation of the ionic solid is the enthalpy of the reaction
The cycle involves equating this enthalpy (which can be measured) to the sum of the enthalpies of a number of steps proceeding from the elements to the ionic solid. The steps are:
1) Atomization of the metal
2) Atomization of the nonmetal
3) Ionisation of the metal
This is obtained from the ionisation potential.
4) Ionisation of the nonmetal
This is electron affinity.
5) Formation of the ionic solids
Equation of the enthalpies gives
from which ΔHL can be found.
Bragg angle → Braggov kut
Bragg angle (Θ) is the angle between an incident X-ray beam and a set of crystal planes for which the secondary radiation displays maximum intensity as a result of constructive interference. British physicist Sir William Henry Bragg and his son Sir William Lawrence Bragg developed a simple relation for scattering angles, now call Bragg’s law.
which relates the angle θ between a crystal plane and the diffracted X-ray beam, the wavelength λ of the x-rays, the crystal plane spacing d, and the diffraction order n (any integer).
The diffraction experiment as presently considered is intended to provide quantitative information on the lattice constant and shape characteristics of the unit cell.
free energy → slobodna energija
Free energy is an energy that is actually available to do useful work. A decrease in free energy accompanies any spontaneous process. Free energy does not change for systems that are at equilibrium.
Citing this page:
Generalic, Eni. "Orthorhombic crystal syst.." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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