Skip to main content Accessibility help
×
Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-11-24T19:54:13.544Z Has data issue: false hasContentIssue false

17 - Hydrogen uranyl phosphate, H3OUO4PO4. 3H2O (HUP), and related materials

Published online by Cambridge University Press:  04 May 2010

Philippe Colomban
Affiliation:
Centre National de la Recherche Scientifique (CNRS), Paris
Get access

Summary

Introduction

Uranyl phosphates and arsenates appear interesting as uranium ores. There are about 200 known uranyl phosphate containing minerals which can be divided into three groups according to the UO2/PO4 ratio. The first group with UO2/PO4 = 1 comprises autunites and uranium phosphate micas; the second has UO2/PO4 > 1, most frequently 3/2 and 4/3, and is illustrated by phospharanglite; the third with UO2/PO4 < 1 is represented by parsonite. The first group of minerals contains usually Cu, Mn, Fe and H while in all groups Pb, Ca and Al are present. The formulae of these minerals have not been established accurately and errors in the determination of the UO2/PO4 ratio often lead to incorrect descriptions. Among the above minerals autunite, CaUO2PO4. 3–6H2O, appears to be the most extensively studied.

As far as hydrogen uranyl phosphate (HUP) is concerned, Beintema noticed – as early as 1938–that ‘true vagabond ions are present in the water layer of the structure’. Thirty years later, Sugitami et al. concluded on the grounds of NMR measurements that water molecules in KUO2PO4.3H2O are highly mobile. Much the same conclusions were reached by Wilkins et al. who observed a high mobility of oxonium ions in H3OUO2AsO4.3H2O. Thus oxonium and water protons diffuse rapidly in the structure of uranyl phosphate or arsenate. In spite of the experimental evidence the question of the true and bulk conductivity has been discussed for a long time.

Type
Chapter
Information
Proton Conductors
Solids, Membranes and Gels - Materials and Devices
, pp. 254 - 271
Publisher: Cambridge University Press
Print publication year: 1992

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×