Appl Note 105

Copyright XRD.US

Powder Diffraction of Clays and Clay Minerals

 

Introduction

Clays and clay minerals are a special class of silicate minerals commonly with  disordered structures. The crystal structures of many clay minerals (Space group, x,y,z coordinated of atoms), are not well defined due to disorder and flexibility of the structures. X-ray powder diffraction pattern of most of clay minerals are site-specific. However, there are well investigated and documented in scientific papers and books describing the powder patterns of clay minerals, which could be used for identification purposes. Separation of clays from soils and  other minerals, as well as preparation of clay minerals for diffraction studies are requiring special techniques.

Clay Minerals Society Links Page
A very extensive set of links which is slanted towards the analysis of clay minerals but also includes lots of more general crystallography, crystal chemistry, X-ray diffraction links and geological links. There are links to some great Earth Science sites here (and Dilbert too). Maintained by Steve Chipera of Los Alamos National Lab.

 

Clay minerals

Clay is a generic term for an aggregate of hydrous silicate earth particles less than 4 micrometers in diameter. They are generally formed by the chemical weathering of silicate-bearing rocks by carbonic acid, but some are formed by hydrothermal activity. Clays are distinguished from other small particles present in soils such as silt by their oblong shape, affinity for water and high plasticity index.

There are three main groups of clays: Kaolinite-Serpentine, Illite, and Smectite. Altogether, there are about thirty different types of "pure" clays in these categories, but most natural clays are mixtures of these different types, as well as other weathered minerals.

Description of clay minerals http://pubs.usgs.gov/of/of01-041/htmldocs/clay.htm

 

Sample Preparation

Sample preparation techniques of clay minerals well discussed in

http://pubs.usgs.gov/of/of01-041/htmldocs/methods.htm

 

Phase Identification

Flow diagram for clay mineral identification

http://pubs.usgs.gov/of/of01-041/htmldocs/images/flow.gif

 

Phase Quantification

Other Application Notes are also available:

 

Note No

Title

Author

Link to ApplNote

AN-101 Powder diffraction of Asbestos XRD.US http://www.xrd.us/applnote/asbestos.htm
AN-102 Powder diffraction of Catalysts XRD.US www.xrd.us/applnote/catalysts.htm
AN-103 Powder diffraction of Ceramics XRD.US www.xrd.us/applnote/ceramics.htm
AN-104 Powder diffraction of Chemicals XRD.US www.xrd.us/applnote/chemicals.htm
AN-105 Powder diffraction of Clays and clay minerals XRD.US www.xrd.us/applnote/clays.htm
AN-106 Powder diffraction of Clinker and cement XRD.US http://www.xrd.us/applnote/clinker and cement.htm
AN-107 Powder diffraction of Composite materials XRD.US http://www.xrd.us/applnote/composite materials.htm
AN-108 Powder diffraction of Corrosion products XRD.US http://www.xrd.us/applnote/corrosion products.htm
AN-109 Powder diffraction for Environmental Appl XRD.US http://www.xrd.us/applnote/environmental.htm
AN-1010 Powder diffraction of Fly ash XRD.US www.xrd.us/applnote/fly ash.htm
AN-1011 Powder diffraction of Forensics XRD.US http://www.xrd.us/applnote/forensics.htm
AN-1012 Powder diffraction of Industrial wastes XRD.US http://www.xrd.us/applnote/industrial wastes.htm
AN-1013 Powder diffraction of Metals and alloys XRD.US http://www.xrd.us/applnote/metals and alloys.htm
AN-1014 Powder diffraction for  Mineral studies XRD.US http://www.xrd.us/applnote/minerals.htm
AN-1015 Powder diffraction for Mining XRD.US http://www.xrd.us/applnote/mining.htm
AN-1016 Powder diffraction of Nanomaterials XRD.US http://www.xrd.us/applnote/nanomaterials.htm
AN-1017 Powder diffraction for Oil drilling XRD.US http://www.xrd.us/applnote/oil drilling.htm
AN-1018 Powder diffraction in Patent process XRD.US http://www.xrd.us/applnote/patent infringment.htm
AN-1019 Powder diffraction of Pharmaceuticals XRD.US http://www.xrd.us/applnote/pharmaceuticals.htm
AN-1020 Powder diffraction of Plastics, fibers & textiles XRD.US http://www.xrd.us/applnote/plastic fiber textile.htm
AN-1021 Powder diffraction of Raw materials XRD.US http://www.xrd.us/applnote/raw materials.htm
AN-1022 Powder diffraction of Refractory materials XRD.US http://www.xrd.us/applnote/refractory materials.htm
AN-1023 Powder diffraction of Rocks XRD.US http://www.xrd.us/applnote/rocks.htm
AN-1024 Powder diffraction of Semiconductors XRD.US http://www.xrd.us/applnote/semiconductors.htm
AN-1025 Powder diffraction of Soils XRD.US http://www.xrd.us/applnote/soils.htm

 

 

 

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