C
SECTION C — CHEMISTRY; METALLURGY
 C

Note(s)

In section C, the definitions of groups of chemical elements are as follows:

  • Alkali metals: Li, Na, K, Rb, Cs, Fr
  • Alkaline earth metals: Ca, Sr, Ba, Ra
  • Lanthanides: elements with atomic numbers 57 to 71 inclusive
  • Rare earths: Sc, Y, Lanthanides
  • Actinides: elements with atomic numbers 89 to 103 inclusive
  • Refractory metals: Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W
  • Halogens: F, Cl, Br, I, At
  • Noble gases: He, Ne, Ar, Kr, Xe, Rn
  • Platinum group: Os, Ir, Pt, Ru, Rh, Pd
  • Noble metals: Ag, Au, Platinum group
  • Light metals: alkali metals, alkaline earth metals, Be, Al, Mg
  • Heavy metals: metals other than light metals
  • Iron group: Fe, Co, Ni
  • Non-metals: H, B, C, Si, N, P, O, S, Se, Te, noble gases, halogens
  • Metals: elements other than non-metals
  • Transition elements: elements with atomic numbers 21 to 30 inclusive, 39 to 48 inclusive, 57 to 80 inclusive, 89 upwards

  
CHEMISTRY
 C02
TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (settling tanks, filtering, e.g. sand filters or screening devices, B01D)
 C02F
TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F 9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)  [3]