Solid State Chemistry Concepts

The coordination number in a crystal lattice refers to the number of nearest neighboring atoms surrounding a central atom.

A crystal structure where one type of atom (typically the smaller one) is displaced from its lattice site to an interstitial position, creating a vacancy and an interstitial defect.

In the hcp (hexagonal close-packed) structure, each atom is surrounded by 12 nearest neighbors.

The formula of a compound in a bcc structure depends on the positions of the atoms within the unit cell.

The relationship between the radius of the atom (r) and the edge length of the unit cell (a) for a face-centered cubic (fcc) unit cell is: a = 2√2r

A diamagnetic substance is a substance that does not have any unpaired electrons and is weakly repelled by an external magnetic field.

In the simple cubic system, there is 1 atom per unit cell.

It is a crystal structure with 3 equal axes and 3 angles, but the angles are 90, 90, and 120 degrees.

A type of point defect in a crystal lattice that affects the overall stoichiometry of the compound. In this defect a cation or anion is missing from its lattice site, creating a vacancy.

One of the seven crystal systems, characterized by three unequal axes and all three angles being 90 degrees.

These are the small particles or molecules that make up the crystal lattice. They are arranged in a specific, repeating pattern, giving the crystal its unique shape.

The smallest repeating unit in a crystal lattice. It is a 3-dimensional representation of the entire crystal structure.

The arrangement of atoms or ions in a three-dimensional structure. This arrangement determines the physical properties of the solid.

A crystal system having 3 axes of equal length and all angles 90 degrees

It refers to the number of atoms or ions that are present in a unit cell. It can be fractional as some atoms might be shared between neighboring unit cells.

It involves the close packing of spheres in a crystal lattice. The FCC arrangement maximizes the space utilization in the crystal structure.

The arrangement of atoms in a crystal lattice where each atom is surrounded by eight neighboring atoms at the corners of a cube.

A type of crystal defect where an atom is missing from its regular position in the lattice, creating a void.

The ability of two or more substances to crystallize in the same crystal structure.

The ability of a substance to exist in more than one crystalline form.

The percentage of space occupied by atoms in a crystal lattice, calculated by the ratio of the volume of atoms to the total volume of the unit cell.

A type of point defect in a crystal lattice where a smaller atom occupies an interstitial position between the regular lattice atoms.

A type of point defect in a crystal lattice where an atom of a different element replaces an atom of the original element in the lattice.

Raoult's law states that the relative lowering of vapor pressure of a solution containing a non-volatile solute is directly proportional to the mole fraction of the solute.

The vapor pressure of a solution is the pressure exerted by the vapor of the solvent above the solution at a given temperature. It is dependent on the number of solute particles present in the solution, as more solute particles will reduce the surface area available for solvent molecules to escape into the vapor phase.

The freezing point depression constant, also known as the cryoscopic constant, is a property of the solvent that describes how much the freezing point of the solvent is lowered when a non-volatile solute is dissolved in it.

Osmotic pressure is the pressure that needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane. For solutions with the same concentration of solute particles, the osmotic pressure will be the same.

Henry's law states that the solubility of a gas in a liquid at a constant temperature is directly proportional to the partial pressure of that gas above the liquid.

The enthalpy change on mixing of two components forming an ideal solution is zero, meaning no heat is absorbed or released during the mixing process. The volume change is also zero, indicating that the total volume of the solution is equal to the sum of the volumes of the individual components.

The ebullioscopic constant (Kb) is a property of the solvent that describes how much the boiling point of the solvent is elevated when a non-volatile solute is dissolved in it.

A type of solution that exhibits positive deviations from Raoult's law is one where the interaction between the solute and solvent molecules is weaker than the interaction between the solvent molecules themselves. This results in a higher vapor pressure for the solution compared to what Raoult's law would predict.

The pressure exerted by the vapor of a pure solvent above its solution at a given temperature.

A solution that deviates from Raoult's law, showing a higher or lower vapor pressure than predicted by the ideal solution model.

A process where a solvent passes through a semipermeable membrane from a region of higher concentration to a region of lower concentration, driven by a pressure gradient.

A measure of the number of particles a solute dissociates into when dissolved in a solvent.

The process of a solute dissolving into ions in a solvent.

Solutions where the osmotic pressure across a semipermeable membrane is equal, preventing net movement of solvent.

The lowering of the freezing point of a solvent when a nonvolatile solute is dissolved in it.

A membrane that allows the passage of certain molecules or ions while blocking others.

In a simple cubic (sc) unit cell, the edge length (a) is equal to twice the radius (r) of the atom. In a body-centered cubic (bcc) unit cell, the edge length (a) is related to the radius (r) by the equation: a = 4r/√3. In a face-centered cubic (fcc) unit cell, the edge length (a) is related to the radius (r) by the equation: a = 2√2r.

A diamagnetic solid is a substance that is weakly repelled by a magnetic field. It has all its electrons paired up, resulting in no net magnetic moment.

A paramagnetic solid is a substance that is weakly attracted to a magnetic field. It has unpaired electrons, creating a net magnetic moment.

A ferromagnetic solid is a substance that is strongly attracted to a magnetic field. It has unpaired electrons, resulting in a strong net magnetic moment, and also has domains of aligned magnetic moments.

Packing efficiency is the percentage of space occupied by atoms in a unit cell. The formula to calculate packing efficiency is: (Volume of atoms in the unit cell / Volume of the unit cell) x 100%.

The relationship between molar mass (M), density (d), and unit cell edge length (a) is given by: d = (ZM) / (a^3N_A). Where Z is the number of atoms per unit cell, N_A is Avogadro's number.

Non-stoichiometric point defects are deviations from the ideal stoichiometric ratio in a crystalline solid. F-centers are a specific type of non-stoichiometric defect. An F-center is created when an anion vacancy is occupied by an electron. This electron is free to move within the crystal, contributing to its conductivity. They are formed when some alkali metal halides are heated in an alkali metal vapor.

Stoichiometric point defects are deviations from the ideal crystal structure in a crystalline solid, but still maintaining the stoichiometric ratio. It is classified into three types: 1. Vacancy defects 2. Interstitial defects 3. Frenkel defects. A substitutional impurity defect is a type of defect where an atom of the host lattice is replaced by an atom of a different element.