Crystal Chemistry

Coordination Polyhdera by Number

100

4

What is tetrahedral?

200

3

What is triangular?

300

8

What is cubic?

400

6

What is octahedral?

500

12

What is close-packed (or large)?

Silicates

100

4+

What is the charge for Si?

200

Feldspar

What is the most abundant mineral in Earth's crust?

300

4

What is the coordination number for Si?

400

[SiO₄]^4-

What is a silicate anion group (or silica tetrahedron)?

500

Silica polymerization

How do silica connect to form different silicate minerals?

Silicates by Color

100

Shiny black with thin layers

What is biotite?

200

Rose

What is rose quartz? (or What is a variety of quartz?)

300

Clear/Transparent

What is quartz?

400

Green

What is olivine?

500

Chalky white

What is kaolinite?

Pauling's rules

100

Pauling's first rule (Hint: Utilizes ionic radii.)

What is the coordination principle?

200

Describes the way in which polyhedra of the same type are connected.

What is Pauling's third rule?

300

Identifies the different between the way in which polyhedra are connected based on the cation charge and CN.

What is Pauling's fourth rule?

400

Occam's razor of crystal chemistry

What is Pauling's fifth rule (What is the rule of parsimony)?

500

Pauling's second rule (Hint: Utilizes CN and charge.)

What is the electrostatic valency principle? (or bond strength principle)

Definitions

100

Smallest repeat unit that defines all the symmetry of a crystal

What is a unit cell?

200

Oppositely charged ion with the shortest distance from the ion of interest.

What is a nearest neighbor?

300

Number of nearest neighbors surrounding an ion of interest.

What is the coordination number?

400

Shape formed when connecting the nearest neighbor ions with the ion of interest in the center.

What is a coordination polyhedron?

500

The component of a polyhedron that is shared with a polyhedron of the same chemistry (e.g., corner, edge, or face).

What is a polyhedral element?