CAS 1309-48-4 appears in our catalog under these names: Magnesium oxide, Puratronic«, 99.995% (metals basis) , Magnesium oxide, ACS, 95.0% min , Magnesium oxide, 99.95% (metals basis) , Magnesium oxide substrate, 10x10x0.5mm, polished one side, , Magnesium oxide substrate, 10x10x0.5mm, polished one side, 1. Offered by: Thermo Scientific (Alfa Aesar). Available pack sizes: 10g, 50g, 250g, 100g, 500g, 2kg, 25g, 1each.