Entanglement and Bell's inequality violation above room temperature in metal carboxylates

In the present work we show that a particular family of materials, the metal carboxylates, may have entangled states up to very high temperatures. From magnetic-susceptibility measurements, we have estimated the critical temperature below which entanglement exists in the copper carboxylate { Cu2 (O2 CH) 4 } { Cu (O2 CH) 2 (2-methylpyridine) 2 }, and we have found this to be above room temperature (Te ∼630 K). Furthermore, the results show that the system remains maximally entangled until close to ∼100 K and the Bell's inequality is violated up to nearly room temperature (∼290 K).