Crystal Structures: NaCl, CsCl, and CaF2

Vocabulary flashcards covering the key properties, parameters, formulas, and diagrams for NaCl, CsCl, and CaF2 crystal structures.

Sodium Chloride Crystal Parameters

A Face Centered Cubic (FCC) crystal system with lattice parameters $a = b = c = 5.64\text{ Á}$ and $α = β = γ = 90^°$.

Sodium Chloride Coordination Number

The coordination number for sodium chloride is $\text{Na} : 6$ and $\text{Cl} : 6$.

Sodium Chloride Physical Properties

Features a bond length of 2.82\text{ Á, a hardness of $2.5$, a melting point of $800^°\text{C}$, an ideal density of $2.17\text{ g/cc}$, and cleavage along $(100)$.

Sodium Chloride Unit Cell Composition

Contains $4$ molecules per unit cell, calculated as $\text{Cl}: 12(1/4) + 1 = 4$ and $\text{Na}: 8(1/8) + 6(1/2) = 4$.

Sodium Chloride Isomorphs

Chemical compounds sharing the same crystal structure as $\text{NaCl}$, including $\text{CaO}$, $\text{MgO}$, $\text{PbS}$, and $\text{KCl}$.

Cesium Chloride Crystal Parameters

A cubic (BCC) crystal system with lattice parameters $a = b = c = 4.24\text{ Á}$ and $α = β = γ = 90^°$.

Cesium Chloride Coordination Number

The coordination number for cesium chloride is $\text{Cs} - 8$ and $\text{Cl} - 8$.

Cesium Chloride Physical Properties

Features a bond length of 3.67\text{ Á, a melting point of $645^°\text{C}$, and an ideal density of $3.99\text{ g/cm}^3$.

Cesium Chloride Unit Cell Composition

Contains $1$ molecule per unit cell, with $\text{Cs}$ located at $(0, 0, 0)$ and $\text{Cl}$ located at $(1/2, 1/2, 1/2)$.

Cesium Chloride Isomorphs and Applications

Isomorphs include $\text{CsBr}$ and $\text{CsI}$. Applications include preparation of electrically conducting glasses and high-pH cancer therapy.

Fluorite Crystal Parameters

A cubic crystal system of $\text{CaF}_2$ (calcium (II) fluoride) with lattice parameters $a = b = c = 5.46\text{ Á}$ and $α = β = γ = 90^°$.

Fluorite Coordination Number

The coordination number for fluorite is $\text{Ca} - 8$ and $\text{F} - 4$.

Fluorite Physical Properties

Features a bond length of 2.35\text{ Á, a hardness of $4$, a melting point of $1340^°\text{C}$, an ideal density of $3.18\text{ g/cc}$, and cleavage along $(111)$.

Fluorite Unit Cell Composition

Contains $4$ molecules per unit cell.

Fluorite Isomorphs and Applications

Isomorphs include $\text{ThO}_2$ and $\text{ZrO}_2$. Used as a flux in the aluminum industry and as a gemstone (though low value due to lack of hardness).

NaCl Octahedral Coordination Diagram

Shows a central chlorine ion bonded octahedrally to 6 surrounding sodium ions in the NaCl lattice structure.

Cesium Chloride Layer Diagram

Illustrates the CsCl unit cell separated into Layer 1 (Cs at $(0,0,0)$) and Layer 2 (Cl at $(1/2,1/2,1/2)$).

Calcium (II) Fluoride Unit Cell Diagram

3D lattice representation of calcium (II) fluoride highlighting the positions of Ca and F atoms.

Dilithium Oxide Unit Cell Diagram

Crystal lattice representation showing the positions of lithium (Li) and oxygen (O) atoms.