Magnesium arsenic reduces its corrosion rate in a salt solution by a factor of nearly ten. Research showed that magnesium's tendency to creep at high-temperatures is eliminated by the addition of scandium and gadolinium. Flammability is greatly reduced by a small amount of calcium in the alloy. Magnesium forms a variety of compounds important to industry and biology, including magnesium carbonate, magnesium chloride, magnesium citrate, magnesium hydroxide (milk of magnesia), magnesium oxide, magnesium sulfate, and magnesium sulfate heptahydrate (Epsom salts). Magnesium has three stable isotopes: , and . All are present in significant amounts (see table of isotopes above). About 79%
U Should've Known Better song entered the "Billboard" Hot 100 chart, where it debuted at number 67 in the week of June 6, 2004, the second-highest debut of the week. "U Should've Known Better" remained twenty weeks on the chart, reaching its peak position of number 19 in its ninth week. It marked the second single from "After the Storm" to reach the top twenty on the Hot 100chart and, as the album's final single, would remain its second highest-charting offering behind leading single "So Gone." Although never released on a CD single or CD maxi single format, "U Should've Known Better" was also