Magnesium hydroxide powder 100% pure usp grade magnesium hydroxide is a source of magnesium, combined as an ionic salt with hydroxide. magnesium hydroxide is often called milk of magnesia because of its milk-like appearance in solution. Magnesium carbonate pharmaceutical secondary standard; certified reference material synonym: magnesium carbonate hydrate, magnesium carbonate cas number 23389-33-5. linear formula mgco 3 · x h 2 o . molecular weight 84.31 (anhydrous basis) ec number 208-915-9. mdl number mfcd00151022. pubchem substance id 329823313. nacres na.24 Magnesium hydroxide carbonate; cas number: 12125-28-9; synonym: magnesium hydroxide carbonate, magnesium carbonate basic; find safc-1.05828 msds, related peer-reviewed papers, technical documents, similar products & more at sigma-aldrich. The magnesium stearate monograph will be incorporated into and become official with the first supplement to usp 39–nf 34. should you have any questions about the magnesium stearate monograph, please contact tong (jenny) liu (240-221-2072 or [email protected] ).