Niklas Langer is the second winner of the Lieselotte-Templeton-Prize 2025, who was awarded for his Master Thesis, which he wrote in the group of Holger Kohlmann in Leipzig.
Niklas has studied Chemistry as well as Mineralogy and Material Sciences at the University of Leipzig with internships in Dresden and Grenoble. He holds a Master’s Degree in both subjects, and after finishing his studies in early 2024, he stayed with his supervisor Holger Kohlmann, and now pursues a PhD.
Brief overview of my work
It would be quite interesting if it were possible to understand and rationalize crystal structures based on very simple mathematical rules. That is pretty much the basic idea behind the project of my master’s thesis, which I am still working on now in my doctoral thesis in the group of Prof. Holger Kohlmann. My work is focused on the utilization of crystal chemical rules to rationalize the coordination in ionic crystals. The crystal chemical rule that I am working with is called the extended coordination number rule and was “invented” by Beck.[1,2] It is distantly related to the more well-known Pauling rules. In a very simplified version, the extended coordination number rule states that the coordination in ionic crystals tends to be as simple as possible. My goal now was to test how well Beck’s rule holds true for a large dataset consisting of the most ionic compounds existing: fluorides. In my master’s thesis, I was able to automate the whole process and show that the agreement between the coordination suggested by the coordination number rule and the experimentally determined structures reached a value of about 80%. This is surprisingly high considering the simplicity of the rule itself. Therefore, I decided to further investigate this topic and try to understand the reasons why ionic crystal structures are the way they are.
What is the most challenging part of the work?
My work appears to be right in the middle between solid-state chemistry, materials informatics, and theoretical chemistry. This is something that I really enjoy, but sometimes challenges arise that I did not expect (e.g., needing to optimize the code of a brute force method because it would take a full year to execute a single calculation). I also found out that some things that are easy for a chemist, like the determination of a coordination number or the assignment of a charge to an element in a compound, can be quite challenging to incorporate into a computer program.
What was your favorite part of this year’s DGK conference?
It was really great to see that so many people showed interest in my research topic, despite it being quite niche and also very theoretical. The DGK conference gave me the opportunity to talk to a lot of people who gave me many useful new ideas for my research (e.g., which other compound classes might be interesting for further investigation). It is quite amazing to see how many different fields of research exist in solid-state chemistry and how different people approach certain scientific problems.
[1] H. P. Beck, Z. Anorg. Allg. Chem. 2022, 648.
[2] H. P. Beck, Z. Kristallogr. 2014, 229, 473.