Lecture 32 & 33 Flashcards
(23 cards)
What does water dissolve
Ionic solids
Polar substances
Non-polar substances (atmospheric gases)
What are the dominant forces of an ionic structure
Ion-ion attraction
What are the dominant forces of a covalent network structure
Covalent bonds
What are the dominant forces of a metallic structure
Metallic bond
What is a unit cell
The smallest repeat unit, which reproduces the entire crystal structure
What is a lattice
An imaginary array of points that describes the arrangement of particles that form a crystal
Consists of all points with identical surroundings
What is a simple cubic
Has 8 corner positions
What is a body-centred cubic
Has 8 corners and 1 center
What is a face centred cubic
Has 8 corners and 6 faces
What is the coordination number
The number of nearest neighbours of a particle in a crystal
How many cells is a corner shared by
1/8 of cells
How many cells is a face shared by
1/2 of cells
How many cells is an edge shared by
1/4 of cells
How many cells are inside a cell (not shared)
1
What is the most efficient packing efficiency
Hcp( hexagonal closet packing): ABAB formation, covers orange spaces
Ccp: cubic closet packing: ABC formation, covers white spaces
What does simple cubic contain
CN: 6
1 atom per cell
What does Body-centred cubic contain (bcc)
CN: 8
2 at atoms per cell
What does hcp contain
CN: 12
6 atoms per cell
What does ccp contain
CN: 12
4 atoms per cell
What are the three common structures in metallic elements
Lattice
Hcp: primitive hexagonal
Ccp: face-cantered cubic
Bcc: body-centred cubic
What are larger anions found in
Close-packing arrangements (ccp or hcp)
What are smaller cations found in
Interstices (small holes)
What are two common structure types for ionic solids
NaCl-type (rocksalt): anions in ccp arrangement, cations in octahedral holes (CN=6)
Li2O-type (antifluoride): anions in ccp arrangement, cations in tetrahedral holes (CN = 4)
