On the Chemical Diversity of the MAX Phases

By Maxim Sokol, Varun Natu, S. Kota, Michel W. Barsoum. Trends in Chemistry, 2019

723 citations recorded by the source corpus.

The Mn+1AXn, or MAX, phases are nanolayered, hexagonal, machinable, early transition-metal carbides and nitrides, where n = 1, 2, or 3, M is an early transition metal, A is an A-group element (mostly groups 13 and 14), and X is C and/or N. These phases are characterized by a unique combination of both metallic and ceramic properties. The fact that these phases are precursors for MXenes and the dramatic increase in interest in the latter for a large host of applications render the former even more valuable. Herein we describe the structure of most, if not all, MAX phases known to date. This review covers ≈155 MAX compositions. Currently, 16 A elements and 14 M elements have been incorporated in these phases. The recent discovery of both quaternary in- and out-of-plane ordered MAX phases opens the door to the discovery of many more. The chemical diversity of the MAX phases holds the key to eventually optimizing properties for prospective applications. Since many of the newer quaternary (and higher) phases have yet to be characterized, much work remains to be done.

Subfields: Biomedical Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/8925b49832f3a25967a5f3ede75d811e7e860d8f

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Citations in the corpus

One MAX phase, different MXenes: A guideline to understand the crucial role of etching conditions on Ti3C2Tx surface chemistry (2020, background): “Indeed, these materials are synthesized by selectively etching the A element from the Mn+1AXn phases, a family of about 150 different members of layered ternary carbides, nitrides or carbonitrides [26], where M is an early transition metal, A is an element mostly from columns 13 or 14 of the periodi”
MXenes: focus on optical and electronic properties and corresponding applications (2020, background): “They are usually categorized by the number of M layers between A layers into mostly “211” (M2AX), “312” (M3AX2), and “413” (M4AX3) [40].”
2D Ti3C2Tz MXene Synthesized By Water-Free Etching of Ti3AlC2 in Polar Organic Solvents (2020, background): “MXenes have a general formula Mn+1XnTz and are so called because they are derived by etching the A atomic layers from the parent MAX (Mn+1AXn) phase, where M stands for an early transition metal, A is mostly a group 13 or 14 element, and X stands for C, N, or B.(9,10) The -ene suffix was added to ma”
The world of two-dimensional carbides and nitrides (MXenes) (2021, background): “The metallic bonding between M- and A-layer atoms in many MAX phases is weaker than the ionic and/or covalent bondingpresent betweenMand Xatoms (3), and therefore it can be brokenusing a kinetically and thermodynamically favorable chemical reaction in an etchant capable of dissolving the reaction pr”