The present invention is directed to compositions comprising at least one layer or at least two layers, each layer comprising a substantially two-dimensional array of crystal cells, having first and second surfaces, each crystal cell having the empirical formula of M.sub.n+1X.sub.n, where M, X, and n are described in the specification, and devices incorporating these compositions.

The invention relates to a method for producing transition metal compounds having the general composition Me.sub.aC.sub.bN.sub.cH.sub.d where Me=transition metal or transition metal mixture, a=1-4, b=6-9, c=8-14 and d=0-8, wherein a reaction mixture consisting of transition metals and/or transition metal compounds and non-condensed or slightly condensed CNH compounds are subjected to a heat treatment, wherein the content of transition metals and/or transition metal compounds is at least 6 mole percent, preferably 10 to 40 mole percent, relative to the reaction mixture. The invention further relates to transition metal compounds produced in such a manner and to uses thereof.

Disclosed is a water-preserving container including a first silver nitride (Ag.sub.3N) sintered-surface layer on a portion of an inner wall or the entire inner wall of the water-preserving container, and a second silver nitride sintered-surface layer on a portion of a lip contact part or the entire lip contact part of the water-preserving container. The water-preserving container prevents the proliferation of bacteria generated according to use and destroys the bacteria, sterilizes and purifies polluted water, and exhibits an early antibacterial effect within 2 hours.

Provided are methods of stabilizing MXene compositions using polyanionic salts so as to reduce the oxidation of the MXenes. Also provided are stabilized MXene compositions.