Synthesis and characterisation of new framework materials

Inorganic framework materials, with structures based on arsenate and phosphate, AsO4<br/>and PO4, tetrahedra and a variety of octahedral metal units, such as hafnium, niobium<br/>and iron, have been synthesised and fully characterised. These materials have been<br/>synthesised by solvothermal techniques and the principal analytical technique to<br/>characterise the resulting single crystals has been Single Crystal X-ray Diffraction.<br/>Supporting analysis was carried out, using techniques such as Powder and Neutron<br/>Diffraction, Thermogravimetric Analysis, Electron Dispersive Spectroscopy and<br/>Infrared Spectroscopy.<br/><br/>Of the hafnium arsenates and phosphates that have been synthesised, several are<br/>fluorinated and one is templated, such as Hf2F2(H(PO4)2)(NH4)2 and<br/>[Hf2F8(AsO4)][DABCO-H2](NH4) respectively. Similar layered frameworks have also<br/>been characterised and reported for titanium, zirconium and niobium. These structures<br/>all offer ion exchange potential, due to their ammonium cations and/or water molecules.<br/><br/>The hydrogen iron phosphates that are discussed include two novel frameworks and<br/>one material which offers an improved model for the mineral lipscombite,<br/>Fe1.34(PO4)OH0.96. One of the new frameworks presented, (NH4)3Fe3(HPO4)6, offers<br/>particularly interesting potential applications as a high capacity battery material via<br/>lithium exchange reactions.<br/><br/>The hydrothermal synthesis of two novel hydrated sodium tungstate structures is also<br/>discussed. One of these materials was found to contain a very high H : Na ratio,<br/>resulting in strong hydrogen bonding and a densely packed framework, which may be of<br/>interest in the field of high density liquids.

Name dc:type.qualificationname

Ph.D.

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Southampton

Year dc:date.issued

2009

Author dc:creator

• Redrup, Kate Victoria

Advisor dc:contributor.advisor

• Weller, Mark