DIFF Subgroup
C01B 33/126 Full Title
Silicon; Compounds thereof ( C01B21/00, C01B23/00 take precedence; persilicates C01B15/14; carbides C01B32/956) > Silicon oxides; Hydrates thereof > Silica; Hydrates thereof, e.g. lepidoic silicic acid
Of 1 combined children, 0 exist in both systems.
1 codes are CPC-only extensions.