The exceptional materials class of so-called MAX phases is defined as hexagonally layered ternary transition metal carbides and (carbo)nitrides. Their general formula is Mn+1AXn with M = early-to-mid transition metal, A = main group element, mostly from groups 13 and 14, and X = C and/or N (n = 1-4). So far, more than 150 MAX phase compounds are known, however, only low percentages are nitrides (7 %) and even less carbonitrides (1%). [1] These low numbers can be attributed to the more demanding synthesis procedure due to the high stability and low diffusion rate of nitrogen-containing compounds. However, intriguing materials properties (e.g. superconductivity or magnetism), that are predicted for new MAX phase compositions, drive experimentalist to push for innovative synthesis strategies.  
By combining non-conventional wet-chemical based methods, such as the so-called “urea-glass method” [2], as well as the “liquid ammonia method” [3], with conventional solid-state preparation techniques, we have developed an alternative two-step process to further expand the hardly investigated field of MAX phase nitrides and carbonitrides by V2GaN and the hitherto unknown carbonitride phases V2GaC1-xNx [4]  and Cr2GaC1-xNx. 
For the new carbonitride phases, the mixed carbon/nitrogen character was proven by means of X-ray powder diffraction, Electron energy loss spectroscopy, and X-ray photoelectron microscopy. SEM micrographs reveal the morphology of the samples, consisting of partly typical anisotropic layered MAX phase structures, as well as needle- and drop-like particles covering the surface. Furthermore, magnetic measurements of the Cr2GaC1-xNx were conducted to gain new insights of the influence of the mixed C/N character. This synthesis method has the potential to open the path to further hitherto unknown nitride and carbonitride MAX phases as well as similar ceramic compounds with interesting properties.   
 
Literature:
 
[1] Sokol, M.; Natu, V.; Kota, S.; Barsoum, M. W. Trends Chem. 2019, 1 (2), 210–223.
[2] Giordano, C.; Erpen, C.; Yao, W.; Milke, B.; Antonietti, M. Chem. Mater. 2009, 21 (21), 5136–5144. [3] Fowles, G. W. A.; Nicholls, D.Q. Rev. Chem. Soc. 1962, 16 (1), 19. [4] Kubitza, N.; Reitz, A.; Zieschang, A.-M.; Pazniak, H.; Albert, B.; Kalha, C.; Schlueter, C.; Regoutz, A.; Wiedwald, U.; Birkel, C. S. Inorg. Chem. 2022, 61 (28), 10634–10641.