Abstract: Provided are 5-layered MXene materials having the formulas M5X4Tx; (M?aM?b)X4Tx (where a+b=5); and (M?aM?b)5X4Tx (where a+b=1). Also provided are related methods, compositions, and applications.

Abstract: A two-dimensional particle including: one or plural layers, the one or plural layers having a layer body represented by: MmXn, wherein M is at least one metal of Group 3, 4, 5, 6, or 7, X is a carbon atom, a nitrogen atom, or a combination thereof, n is 1 to 4, m is more than n but not more than 5, and a modifier or terminal T existing on a surface of the layer body, wherein T is at least one selected from a hydroxyl group, an amine group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom and a hydrogen atom; a metal cation is at least one cation selected from Na and K, and a content of Li in the two-dimensional particle is less than 0.002% by mass.

Abstract: Provided are 5-layered MXene materials having the formulas M5X4Tx; (M?aM?b)X4Tx (where a+b=5); and (M?aM?b)5X4Tx (where a+b=1). Also provided are related methods, compositions, and applications.

Abstract: Provided are methods of using MXene compositions to selectively adsorb analytes such as toxic industrial chemicals, opioids, and nerve agents. Also provided are MXene compositions configured to effect selective adsorption of analytes.