Inorganic - Atomic X-Ray Spectroscopy

Front 1

X ray spectroscopy, like optical spectroscopy is based on _________, absorption,_______ , fluorescence, and diffraction electromagnetic radiation

Back 1

emission

scattering

Front 2

What is the range of elements that can be analyzed?

Back 2

Atomic number above sodium

Front 3

What are the two types?

Back 3

X-ray fluorescence Spectroscopy (XFS) and X-ray diffraction (XRD)

Front 4

Principle of XFS

Back 4

X-ray beam causes e- to eject. When electrons fall in the empty spot, they emit fluorescence.

Front 5

Types of analysis that can be performed

Back 5

Qualitative

Quantitative

Non-destructive

Front 6

In XFS:

Elements are identified by ________ __________

Concentrations are identified by _________

Back 6

characteristic radiation

intensity and comparison with a standard

Front 7

What is the principle of XRD?

Back 7

X-rays are diffracted by the planes of a crystal

Front 8

How are elements and concentrations determined in XRD ?

Back 8

Positions and intensities of diffracted X-Rays

Can tell crystal structure, solid composition, particle size, disorder, etc

Front 9

What is the theory of X-ray fluorescence?

Fluoresced rays are separated using an analyzer crystal mounted on an angle measuring device called a __________. The intensity is measured by a __________. The separation of the emitted x-rays depends on ________.

Back 9

goniometer

scintillation counter

Bragg's Law

Front 10

What is the Bragg's Law eg?

Back 10

where n is a positive integer and λ is the wavelength of incident wave.

Front 11

Name 5 advantages for X-ray fluorescence

Back 11

1. Little sample preparation

2. Simple spectra (only K and L shells involved)

3. Non-destructive

4. Sample relationship between sensitivity and atomic number

5. No deviation from linearity

6. Speed

Front 12

Name 5 disadvantages for X-ray fluorescence

Back 12

1. Can't analyze elements lower than sodium

2. Matrix interference

3. Not as sensitive as emission

4. High initial cost

5. Sample Homogeneity is critical

Front 13

Name five interferences in x-ray quantitative analysis

Back 13

1. Grain Size

2. Thickness of sample

3. Nature of Surface

4. Matrix interference

5. Elemental enhancement effects

Front 14

XDR:

From Bragg's law we get ___ values, which are located in index's so can do a ______ analysis

Back 14

d

qualitative

Front 15

X ray powder diffraction is unique, it is the only analytical method capable of providing _______ and _______ information about a compound present in a solid sample.

Back 15

qualitative, quantitative

Front 16

Advantages of XRD

Back 16

1. Works with crystalline material (metals & minerals)

2. Small sample is required

3. Identifies compounds present

4. non-destructive

Front 17

Disadvantages of XRD

Back 17

1. Only capable of identifying substances in the powder diffraction file

2. Substances present in low concentrations may not show up.