Compute diffusion coefficients for the interdiffusion of carbon in both (a) α-iron (BCC) and (b) γ-iron (FCC) at 950˚C. Assume that D0 for the interdiffusion of carbon in α-iron and in γ-iron are 1.1 × 10-6 and 2.3 × 10-5 m2/s, respectively, and that Qd are 80 and 148 kJ/mol, respectively.

Answer is: sulfur, arsenic, selenium, silicon  and antimony.

1) Sulfur (S) can form, for example, sulfuric acid (H₂SO₄) or acidic oxide, sulfur(VI) oxide (SO₃).

2) Arsenic (As) can form arsenous acid (H₃AsO₃).

3) Selenium (Se) can form selenic acid (H₂SeO₄).

4) Silicon (Si) can form orthosilicic acid Si(OH)₄ and metasilicic acid SiO(OH)₂.

5) Antimony (Sb) can form antimonic acid, as the hydrate HSb(OH)₆.