Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Transition Metal Selenites (Mn, Co, Ni, Fe, Cu, Zn and Cd)

29.09.2005


The work involved a multidisciplinary task, undertaking the study of phases of mineralogical and physico-chemical interest. Selenites were synthesised, given that they are a new field and likely to present original physical properties. Their study was carried out using crystallographic methods and the behaviour of their physical properties was investigated.



As a result of this research, twenty-four selenites of different transition metals were synthesised. These were grouped as a function of the conditions of the pressure and the temperature employed in their synthesis, differentiating three blocks of eight phases each. New polymorphs obtained were: Mn(SeO3).H2O(A,B), in low pressure and temperature conditions, Mn3(SeO3)3.H2O and Mn4(SeO3)4.H2O phases in moderate pressure and temperature conditions, and Mn(SeO3)(A,B) polymorphs in high pressure and temperature conditions.

The aims were, apart from obtaining new selenites, the undertaking of a structural analysis by means of X-ray diffraction in monocrystalline and in polycrystalline samples. The studies carried out enabled the elucidation of the crystallographical parameters for each phase. The X-ray diffraction diagrams for the polycrystalline sample showed a significant absence of impurities. Finally, the structures of twenty-four phases, obtaining the link distances, the distortion and the equilibrium of the loads of the units present, were investigated.


Studies were undertaken of thermal properties (thermogravimetric and thermodiffractometric), spectroscopic properties (infrared, diffuse reflectance, luminescence and Mössbauer) and magnetic properties (magnetic susceptibility and electronic paramagnetic resonance) of the selenites obtained.

The thermogravimetric and thermodiffractometric analyses show an initial loss of the water molecules and the posterior decomposition of all phases. After elimination of selenium in the form of SeO2(g), the formation of simple oxides of the metals present in the initial structures takes place.

The analyses of the infrared spectra of the selenites show the characteristic bands for the (SeO3)2- selenite groups, in the interval of frequencies from 1000 to 400 cm-1. The diffuse reflectance spectra present the characteristic bands of cations, in all case obtaining a certain degree of covalency. Manganese compounds show luminescence phenomena at temperatures of liquid He. The emission and excitation spectra present bands belonging to manganese(II) ions in high-spin octahedric environments.

Magnetic measurements indicate the presence of predominantly antiferromagnetic interactions, with a part of the samples showing ferromagnetic phenomena at low temperatures. One of the synthesised phases, selenite with the Cu2O(SeO3) formula, present global ferromagnetic behaviour.

Irati Kortabitarte | alfa
Further information:
http://www.basqueresearch.com

More articles from Earth Sciences:

nachricht NASA examines newly formed Tropical Depression 3W in 3-D
26.04.2017 | NASA/Goddard Space Flight Center

nachricht Early organic carbon got deep burial in mantle
25.04.2017 | Rice University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>