CAS 7440-58-6 appears in our catalog under these names: Hafnium - Hf @ 1000 µg/mL in 5% HCl, Hafnium Standard: Hf @ 1000 µg/mL in 5% HCl, Hafnium Standard: Hf @ 1000 ug/mL in 2% HNO3/0.5%HF, Hafnium Standard: Hf @ 10000 µg/mL in 4% HNO3, 2% HF, Hafnium Standard: Hf @ 10000 µg/mL in 5% HCl. Offered by: VHG, Chemat, Thermo Scientific (Alfa Aesar), Sigma-Aldrich. Available pack sizes: 50ml, 500ml, 100ml, 250ml, 5g, 25g, 10g, 50g.