  In the present work we show that a special 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 cooper carboxylate
\{Cu$_2$(O$_2$CH)$_4$\}\{Cu(O$_2$CH)$_2$(2-methylpyridine)$_2$\}, and we have
found this to be above room temperature ($T_e \sim 630$ K). Furthermore, the
results show that the system remains maximally entangled until close to $\sim
100$ K and the Bell's inequality is violated up to nearly room temperature
($\sim 290$ K).
