Chromium(III) nicotinate contains three nicotinic acid units per chromium ion; that is, it is the trinicotinate of chromium(III). The substance that is used in supplements and called "chromium polynicotinate" is said to be a mixture of the trinicotinate and the dinicotinate, with the former dominating.2
Preuss HG, Bagchi D, Bagchi M, Rao CV, Dey DK, Satyanarayana S (May 2004). "Effects of a natural extract of (-)-hydroxycitric acid (HCA-SX) and a combination of HCA-SX plus niacin-bound chromium and Gymnema sylvestre extract on weight loss". Diabetes, Obesity & Metabolism. 6 (3): 171–80. doi:10.1111/j.1462-8902.2004.00328.x. PMID 15056124. S2CID 36237508. /wiki/Doi_(identifier) ↩
European Food Safety Authority (EFSA) (2008). "Mixture of chromium di- and tri-nicotinate as a source of chromium added for nutritional purposes in food supplements and in foods for particular nutritional uses". The EFSA Journal. 887: 1–24. doi:10.2903/j.efsa.2008.887. https://doi.org/10.2903%2Fj.efsa.2008.887 ↩