Technetium tetrachloride has been prepared from the reaction of technetium metal with excess chlorine in sealed Pyrex ampules at elevated temperatures. The product was characterized by single-crystal and powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and alternating-current magnetic susceptibility. Solid TcCl4 behaves as a simple paramagnet from room temperature down to 50 K with mu(eff) = 3.76 mu B. Below 25 K, TcCl4 exhibits an antiferromagnetic transition with a Neel temperature (T-N) of similar to 24 K. The thermal behavior of TcCl4 was investigated under vacuum at 450 degrees C; the compound decomposes stepwise to alpha-TcCl3 and TcCl2.