Trivalent chromium (Cr(III)) ion is possibly required in trace amounts for sugar and lipid metabolism, although the issue remains in debate. In larger amounts and in different forms, chromium can be toxic and carcinogenic.The most prominent example of toxic chromium is hexavalent chromium (Cr(VI)).aturally occurring chromium is composed of three stable isotopes; 52 Cr, 53 Cr and 54 Cr with 52 Cr being the most abundant (83.789% natural abundance). 19 radioisotopes have been characterized with the most stable being 50 Cr with a half-life of (more than) 1.8 × 10 years, and 51 Cr with a half-life of 27.7 days.