Oxidation, Reduction, and Simple Solid Structures

Flashcards covering Latimer and Pourbaix diagrams, chemical extraction of elements, and the fundamental structures and bonding of simple solids.

Latimer diagram

A diagrammatic presentation of an element where numerical values of the standard potential (in volts) are written over horizontal lines connecting species with the element in different oxidation states.

Standard Gibbs energy in Latimer diagrams

The value used to obtain the standard potential of a couple that is the combination of two other couples, calculated as $\Delta_rG^{\ominus} = -\nu FE^{\ominus}$.

Disproportionation

The tendency of a species to react into its two neighbors in a Latimer diagram, which is favorable if the potential to the right of the species is higher than that to the left ($E^{\ominus}(R) > E^{\ominus}(L)$).

Pourbaix diagram

A map of potential and pH conditions under which chemical species are thermodynamically stable in water, showing the relations between redox activity and Brønsted acidity.

Pidgeon process

A chemical reduction method used to extract Magnesium, involving the reaction $MgO(s) + C(s) \rightarrow Mg(l) + CO(g)$.

Claus process

A process for obtaining sulfur through chemical oxidation, involving the reactions $2H_2S + 3O_2 \rightarrow 2SO_2 + 2H_2O$ and $2H_2S + SO_2 \rightarrow 3S + H_2O$.

Metallic bonding

Bonding that occurs when each atom loses one or more electrons to a common "sea," producing molecular orbitals that extend throughout the sample.

Ionic bonding

A type of bonding where ions of different elements are held together in rigid, symmetrical arrays due to the attraction between their opposite charges.

Delocalized bonding

Nondirectional bonding found in metals that allows layers of atoms to slip past one another, making the material malleable and ductile.

Unit cell

An imaginary parallel-sided region (parallelepiped) and subdivision of a crystal that, when stacked together without rotation or reflection, reproduces the crystal.

Crystal lattice

A three-dimensional, infinite arrangement of lattice points, where each point is surrounded in an identical way by neighboring points, defining the basic repeating structure.

Lattice parameters

Defined as the lengths ($a$, $b$, $c$) and angles ($\alpha$, $\beta$, $\gamma$) that determine the size and shape of a unit cell.

Triclinic system

A crystal system where lattice parameters satisfy $a \neq b \neq c$ and $\alpha \neq \beta \neq \gamma \neq 90^{\circ}$.

Cubic system

A crystal system where lattice parameters satisfy $a = b = c$ and $\alpha = \beta = \gamma = 90^{\circ}$, with four three-fold rotation axes.

Primitive unit cell

A unit cell that contains exactly one lattice point.

Body-centered cubic (bcc) lattice

A lattice type containing two lattice points in each unit cell, with the additional point at the center due to a displacement of $(+1/2, +1/2, +1/2)$.

Face-centered cubic (fcc) lattice

A lattice type containing four lattice points in each unit cell.