Abstract
In this letter, we present an experimental observation of entanglement in a spin chain formed in the layered compound CaMn2Sb2. The presence of entanglement was investigated through a measurable quantity, the magnetic susceptibility. The entanglement witness obtained from the measurement is presented as a function of applied field for fixed temperatures. The presence of entanglement is observed even for reasonably high temperatures and applied fields. Since entanglement seems to occur naturally in this material, we suggest it to be used as an entanglement reservoir.