Patent ID: 7101427

Claim:
A particulate metal oxide, optionally hydrophobic, having an extinction coefficient at 524 nm (E 524 ) in the range from 0.2 to 0.7 l/g/cm, an extinction coefficient at 450 nm (E 450 ) in the range from 0.5 to 1.5 l/g/cm, an extinction coefficient at 360 nm (E 360 ) in the range from 5 to 8 l/g/cm, an extinction coefficient at 308 nm (E 308 ) in the range from 40 to 60 l/g/cm, a maximum extinction coefficient E(max) in the range from 45 to 75 l/g/cm, and a λ(max) in the range from 260 to 290 nm, wherein the extinction coefficient E, is calculated from the equation A=E.c.l, where A=absorbance, E=extinction coefficient in liters per gram per cm and l=path length in cm, for a sample of the particulate metal oxide at a dilution of 1:20,000 in a spectrophotometer at a path length of 1 cm.