The structure of materials at the atomic scale is a core component in the Materials Science and Engineering (MSE) study. This course aims to develop the student’s ability to describe materials’ crystal structure and defects, and to understand how they affect materials’ properties and performance. It also prepares MSE students to better understand other courses on materials properties, processing, and characterization. The principles learnt from this course will be useful for students in designing / selecting materials. The following content will be covered in this course: Crystallography, Metal structures, Ceramic structures, Crystalline defects, Amorphous solids and Quasicrystals. By the end of this course, the students are expected to be able to 1. Describe and understand various types of lattice structures (Bravais lattices). 2. Express crystallographic directions and planes and calculate their properties (vector length, unit cell volume, d-spacing, linear density, planar density, atomic / ionic packing factor etc.) and the geometric relationship. 3. Describe and explain representative metal and ceramic structures. 4. Define different types of defects in metals and ceramics. 5. Determine how crystalline defects would affect material properties based on basic principles and propose possible solutions