Bismuth niobate (BiNbO4) is widely used in multilayer RF and microwave components such as capacitors and chip layer capacitors. This compound exhibits two main structural forms (polymorphs) alpha and beta. Both alpha and beta phases are potential antiferroelectric (AFE) materials which may be used for energy storage. The alpha polymorph shows interesting dielectric properties with transitions to ferroelectric and paraelectric phases. We propose to study details of these dielectric phase transitions, with a view to understanding the nature of these very subtle transitions. Further heating BiNbO4 results in the appearance of two previously unknown polymorphs in this system, gamma above 1024C and delta above 1070C. We propose to analyse the structures of these two polymorphs with a view to establishing their relationship with the lower temperature alpha and beta phases.