Chapter 12- Solids, Crystals etc

unit cell

simple cubic

atoms touch along edge

face-centered cubic

atoms touch along face diagonal

body-centered cubic

atoms touch along body diagonal

corner atoms in simple cubes are shared by

8 unit cells

relationship between the dimension of the unit cell and the radius of the atom

radius of the atom = half the dimension of the atom (?)

the diagonal across the face of the primitive unit cell cube is equal to (??)

4 times radius

metal alloy

mixture of metals- can be lacking a whole # ratio between elements

steel is an alloy of ___ and an array of other atoms

iron

coordination number

the number of atoms/ions with which an atom or ion has close contact

• for primitive cube, N=6

• For BCC, N=8

• For FCC, N=12

cubic holes

cubic packing = cubic hole (?)

tetrahedral holes

exist in face centered cubes

octahedral holes

if x-rays are in phase with each other, they’ll appear ___, if they’re out of phase they’ll appear ___

bright, dark

BC+CD=2d Sin O = n(wavelength)

allotrope

different structural form of the same element

nanoparticle

particle w/ diameter less than 10^-7

crystalline solids

ordered arrays of atoms, ions, or molecules

amorphous solids

random or disordered arrangements of particles

metallic solids

ordered arrays of atoms held together by metallic bonds

molecular solids

• what most non-metals form

neutral, covalently bonded molecules held together by intermolecular forces

atomic solids

• what noble gases form

only weak dispersion forces between atoms

covalent network solids

extended arrays held together by covalent bonds

ionic solids

• formed by ionic compounds

monoatomic or polyatomic ions held together by ionic bonds