Scientists obtain new results in the study of inorganic pigments with apatite structure

October 31, 2018, Lobachevsky University
High-purity sample of barium hypomanganate chloride. Credit: Lobachevsky University

Compounds with the apatite structure differ from most classes by the variety of their chemical compositions. To create such substances, most chemical elements can be used, while the characteristics of the crystalline structure of apatite will be preserved. The resulting variety of chemical compositions also determines a wide range of physico-chemical properties and performance characteristics of the materials created on the basis of substances of this structural type.

In addition to the possibility of changing the substance's chemical composition over a wide range, it is also possible to stabilize in the crystal structure of such substances some elements in the less common oxidation states, primarily, the manganese and chromium atoms in the +5. As a rule, these elements under the conditions of various processes are subjected to disproportionation—a simultaneous increase and decrease of the oxidation state to more stable states: +6 and +4 for manganese and +6 and +3 for chromium.

The search for a crystalline matrix that promotes stabilization of the rare oxidation of manganese and chromium is relevant due to the fact that such compounds have a persistent green or blue color (or their intermediate shades). Therefore, it is possible to use them as inorganic pigments, which, in addition to their specific shades, feature a sufficiently .

The studies of with the apatite structure have been carried out at the Faculty of Chemistry of the Lobachevsky University by the team headed by Prof. A.V. Knyazev and Dr. E.N. Bulanov since 2010. The team's latest achievements include obtaining a high-purity sample of the composition Ba5(MnO4)3Cl and its physico-chemical characterization. According to Evgeny Bulanov, within the framework of this research, the features of the and chemical environment were established, allowing the degree of manganese oxidation to be stabilized.

"In addition, the isobaric heat capacity of the substance was measured for the first time. During the experiment, the anomalous behavior of the compound was also found below the temperature of 15K, which can be explained by spin ordering," says Evgeny Bulanov.

Explore further: Scientists investigate inorganic biomaterials with antimicrobial properties

More information: A.V. Knyazev et al, Synthesis, structure and thermodynamic properties of Ba5(MnO4)3Cl apatite, The Journal of Chemical Thermodynamics (2018). DOI: 10.1016/j.jct.2018.09.004

Related Stories

Scientists precisely measure the charge state of manganese

September 5, 2016

Most atoms lose or gain just a few negatively charged electrons from their surroundings, but not manganese. This element can donate up to seven electrons or wrench as many as three electrons away, abilities that can have ...

Size matters in crucial redox reactions

October 12, 2010

(PhysOrg.com) -- Particle size has a far more dramatic impact on chemical reactivity than previously thought, according to new research from UC Davis. The results have implications for understanding a wide range of vital ...

Pigment discovery expanding into new colors

July 27, 2011

Chemists at Oregon State University have discovered that the same crystal structure they identified two years ago to create what may be the world's best blue pigment can also be used with different elements to create other ...

Researchers developing materials for quantum computing

March 26, 2018

Creation of innovative materials is one of the most important areas of modern science. Active development of Industry 4.0 requires new properties from composite elements of electronics. Researches of scientists from South ...

Novel nano material for quantum electronics

September 10, 2018

An international team led by Assistant Professor Kasper Steen Pedersen, DTU Chemistry, has synthesized a novel nano material with electrical and magnetic properties making it suitable for future quantum computers and other ...

Recommended for you

First microarrayed 3-D neuronal culture platform developed

November 14, 2018

Neuronal development is often regulated by the graded distribution of guidance molecules, which can either attract or repel the neuronal migration or neurite projection when presented in a format of concentration gradients, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.