structures of solids

Question 1

Lattice definition

Answer 1

3-dimensional, infinite array of points, the lattic points, each of which is surrounded in an identical way by neighbouring points, and which defines the basic repeating structure of a crystal

Question 2

Crystal structure definition

Answer 2

Obtained by associating one or more identical structural units (such as molecules or ions) with each lattice point

Question 3

Unit cell definition

Answer 3

Imaginary parallel-sied region (“parallelepiped”) from which the entire crystal can be built up by purely translational displacements

Question 4

Lattice parameters definition

Answer 4

The angles and lengths used to define the size and shape of a unit cell

Question 5

Primitive unit cell definition

Answer 5

Has just one lattice point in the unit cell and the translational symmetry present is just that on the repeating unit cell

Question 6

What is the coordination number of a sphere in a close-packed arrangement

Answer 6

12

Question 7

Rutile

Answer 7

MX2
hcp arrangement of anions with cations in half Oh holes
octahedral around cations and triangular around anions

Question 8

Rutile examples

Answer 8

CaF2, UO2, TiO2

Question 9

Cadmium chloride, CdCl2

Answer 9

MX2
ccp arrangement of anions with cations in half Oh holes (alternating layers)
octahedral around cations and trigonal pyramidal around anions

Question 10

Cadmium chloride, CdCl2 examples

Answer 10

CdCl2, MnCl2, NiCl2

Question 11

Fluorite

Answer 11

MX2
primitive cubic arrangement of anions with cations in half cubic holes
cubic around cations and tetrahedral around anions

Question 12

Fluorite examples

Answer 12

CaF2, UO2

Question 13

Cadmium Iodide, CdI2

Answer 13

MX2
hcp arrangement of anions with cations in half Oh holes (alternating layers)
octahedral around cations and trigonal pyramidal around anions

Question 14

Cadmium iodide, CdI2 examples

Answer 14

CdI2, TiI2, TiCl2, Mg(OH)2

Question 15

Rhenium Trioxide, ReO3

Answer 15

MX3
primitive cubic arrangement of cations with anions at the centre of each edge
octahedral around cations, linear (2) around anions

Question 16

Rhenium trioxide, ReO3 examples

Answer 16

WO3, AlF3, Fe(CN)3

Question 17

Cesium Iodide, CsCl

Answer 17

MX
Primitive cubic arrangement of anions with cations in all cubic holes
cubic around cations and cubic around anions

Question 18

Cesium iodide, CsCl examples

Answer 18

CsCl, CsI, CsBr, NH4Cl, NH4Br

Question 19

Nickel Arsenide, NiAs

Answer 19

MX
hcp arrangement of anions with cations in all Oh holes
octahedral around cations and trigonal prismatic around anions

Question 20

Nickel arsenide, NiAs examples

Answer 20

NiAs, CoP

Question 21

Rocksalt, NaCl

Answer 21

MX
ccp arrangement of anions with cations in all Oh holes
octahedral around cations and octahedral around anions

Question 22

Rocksalt, NaCl examples

Answer 22

NaCl, MnO

Question 23

Wurzite

Answer 23

MX
hcp arrangement of anions with cations in half Td holes
tetrahedral around cations and tetrahedral around anions

Question 24

Wurzite examples

Answer 24

ZnS, BeO, SiC, SiGe

Question 25

Zinc Blende

Answer 25

MX ccp arrangement of anions with cations in half Td holes tetrahedral around cations and tetrahedral around anions

Question 26

Zinc Blende examples

Answer 26

ZnS, CuCl

Question 27

Perovskite

Answer 27

ABO3 corner sharing octahedra where the centres are B-site cations and the corners are the anions, A site cations are in the centre of corner sharing octahedra A coord = 2, B = 6, anions = 6 (2B and 4A)

Question 28

Perovskite examples

Answer 28

SrTiO3, KNbO3

Question 29

What are the two polytypes formed by construction of close-packed layers

Answer 29

hexagonal ABAB cubic ABCA

Question 30

what metals adopt the hexagonal close packed structure

Answer 30

Mg, Ti, Zn, and Cd

Question 31

what metals adopt the cubic close packed structure

Answer 31

Al, Cu, Au, and Ni