High-pressure x-ray diffraction study of $Ta4AlC3$ Available to Purchase

Using a synchrotron radiation source and a diamond anvil cell, we measured the pressure dependence of the lattice parameters of a recently discovered phase, $Ta4AlC3$⁠. This phase adopts a hexagonal structure with the space group $P63∕mmc$⁠; at room conditions, the $a$ and $c$ parameters are 3.087(5) and $23.70(4)Å$⁠, respectively. Up to a pressure of $47GPa$⁠, no phase transformations were observed. Like $Ta2AlC$⁠, but unlike many related phases such as $Ti4AlN3$⁠, $Ti3SiC2$⁠, $Ti3GeC2$⁠, and $Zr2InC$⁠, the compressibility of $Ta4AlC3$ along the $c$ and $a$ axes are almost identical. The bulk modulus of $Ta4AlC3$⁠, $261±2GPa$⁠, is $≈4%$ greater than that of $Ta2AlC$⁠. Both, however, are $≈37%$ lower than the $345±9GPa$ of TaC.