Question

Crystal Lattices EXPERIMENT B-261 PRE-LAB QUESTIONS Name Daniel Gonzalez Date 10 3019 1 What is a unit cell? - The smallest pahay wit that has all of the characteristische au t o atomsons, o molecules in the Solid sed or strictures of Solids the sinal laties of ams, insp e ctes, in this case, to a Crystalline solid . Vuit alls reflect the Stoichiority of the colid 2 What is a crystal lattice? - in a three-dimensional lattice unit alls Wibe builoling blocks vnit Cells. of solids, (lattices can be built by assombling three-dimensional Crystalline is the base of these Herdina 3 Fill in the following table. Crystal Lattice Types for Metals Number of Atoms! Unit Cell 14 sen x vs + all | Packing Efficiency Number of Metals** Primitive cubic pc Jika tal-Body-centered cubices 2 et alors per weit all 196 Snet a tows per wit Cell Hexagonal close packing Cubic close packing foc u t atoms per unit cell 74% fotce - Onteered wbic *Packing Efficiency - % of space in unit cell occupied by atoms **Number of metals with a particular type of crystal lattice 4 What are the three most frequently occurring types of crystal lattices in metaly - Primitive cubic (pc)- polonium 8 ( corners of a cuy a cow s tem within a writuell within a witcell) = inet atom for thit cell. - body contered cubic (bcc) alkali metals 88 : A z net atoms pr mitcell (6 faces of cabe) (1206 an atom within a voit all not face onood atoms within a fee unit cell. - face centred cubic (fcc) - nickel, copper, aluminum &

Answer 1

Hexagonal Closed Packing and Cubic Closed Paking have similar packing efficiency i,e; 74% whereas simple cubic is of 52.40% and body centered is 68% packing efficiency .

Primitive cubic has 6 metal coordination number .

Body centered has 8 metal coordination number.

In HCP and CCP both having 12 Coordination number of metals .