topic 4🅱️

Question 1

describe rutile,, TiO2

Answer 1

array of Ti 4+ cations

O 2- anions in interstitial sites

Ti 4+
O. 2-

Question 2

describe rutile fully

Answer 2

Ti 4+
O 2-

TiO2

array of Ti with O in interstitial sites

Ti,, 0,1 and 1/2 in the middle
O at 0,1 and 0,1 diagonal
O at 1/2, 1/2 diagonal

Ti: cn = 6,, distorted octahedral

O: cn = 3,, trigonal planar coordination

Question 3

describe caesium chloride briefly

Answer 3

CsCl

primitive!!

Cs+
Cl-

primitive cubic packing of Cs+ cations with Cl- in cubic interstitial sites

Question 4

describe Caesium chloride fully

Answer 4

CsCl

Cs+ primitive cubic packing
Cl- cubic interstitial sites

Cs, cube,, 0,1
Cl- centre,, 1/2

both Cn = 8

Question 5

perovskite

Answer 5

CaTiO3

primitive cubic packing of Ca+ with O2- in faces
Ti 4+ in the centre of cell

Ca 2+ cn = 12
Ti 4+ cn = 6 (octahedral)

Question 6

what is a normal spinel

Answer 6

MgAl2O4

ccp array of O2-
Mg 2+ 1/8 tetrahedral holes
Al 3+ in 1/2 octahedral holes

Mg = 4,, tetrahedral geometry

Al = 6 ,, octahedral geometry

Question 7

what is an inverse spinel

Answer 7

Mg2TiO4

ccp array of O2- cations
Ti 4+ in 1/2 octahedral holes
Mg in 1/2 octahedral holes and all tetrahedral holes

Mg cn: 4,6
Ti cn: 6

Question 8

what is lecture 4 focused on

Answer 8

structures that arent based on close packing