Chromium(II) hydride, systematically named chromium dihydride and poly(dihydridochromium) is pale brown solid inorganic compound with the chemical formula (CrH2)n (also written ([CrH2])n or CrH2). Although it is thermodynamically unstable toward decomposition at ambient temperatures, it is kinetically metastable. Chromium(II) hydride is the second simplest polymeric chromium hydride (after chromium(I) hydride). In metallurgical chemistry, chromium(II) hydride is fundamental to certain forms of chromium-hydrogen alloys.