St Petersburg University researchers synthesise the biomineral moolooite and refine its crystal structure

Moolooite, a naturally occurring hydrated copper oxalate, was first discovered in 1986 in Australia. According to Alina Izatulina, Principal Investigator of the project, Senior Researcher at the Department of Crystallography at St Petersburg University, in nature, this mineral is often associated with the activity of living organisms. For instance, moolooite is found in lichen species growing in areas of copper mineralisation.

The research findings are published in the International Journal of Molecular Sciences.

‘The crystallisation of hydrated copper oxalate — moolooite — is very interesting. Since copper is a toxic element, the formation of insoluble copper complexes can be put to use in bioremediation technologies. For example, oxalate-producing microorganisms can be used to purify soil from copper,’ said Alina Izatulina.

Moolooite also serves as a precursor for the production of widely used nano-forms of copper oxides. The researchers at St Petersburg University were able to synthesise a single crystals of moolooite, suitable for X-ray diffraction analysis.

‘The crystal structure of moolooite was not reliably determined, although it was almost 40 years since its discovery. We were able to obtain single crystals of a synthetic analogue of moolooite in the laboratory. The synthesised crystals were then studied in detail using the equipment of the St Petersburg University Research Park. We were able to explain the absence of good-quality single crystals both in nature and synthetic experiments. The difficulty in obtaining single crystals and refining the crystal structure is due to the incorporation of water molecules into the copper-oxalate chains. The amount of water that can be incorporated into the crystal structure of moolooite can vary substantially, causing instability of the structure,’ said Alina Izatulina, Senior Researcher at the Department of Crystallography at St Petersburg University.

St Petersburg University, the oldest university in Russia, was founded on 28 January (8 February) 1724. This is the day when Peter the Great issued a decree establishing the University and the Russian Academy of Sciences. Today, St Petersburg University is a world-class scientific, educational and cultural centre. In 2024, St Petersburg University will celebrate its 300th anniversary.

The plan of events during the celebration of the anniversary of the University was approved at the meeting of the Organising Committee for the celebration of St Petersburg University’s 300th anniversary. The meeting was chaired by Dmitry Chernyshenko, Deputy Prime Minister of the Russian Federation. Among the events are the naming of a minor planet in honour of St Petersburg University; the issuance of bank cards with a special design; the creation of postage stamps dedicated to the history of the oldest university in Russia; and the branding of the aircraft of the Rossiya Airlines to name just a few. The University has launched a website dedicated to the upcoming holiday. The website contains information about outstanding University staff, students, and alumni; scientific achievements; and details of preparations for the anniversary.

Aside from being of fundamental importance for science, the research findings are also of practical relevance for improving methods of copper removal from the environment. The research was supported by a grant from the Russian Science Foundation (project № 19-17-00141).

The researchers used equipment of the resource centres: Centre for X-ray Diffraction Studies; Thermogravimetric and Calorimetric Research Centre; and Centre for Geo-Environmental Research and Modelling (GEOMODEL).