QUINONES  , in organic See also:

• CHEMISTRY
• CHEMISTRY (formerly "chymistry"; Gr. xvµela; for derivation see ALCHEMY)

chemistry, a See also:

• GROUP

group of compounds in which two See also:

• HYDROGEN [symbol H, atomic weight x-oo8 (0=16)]

hydrogen atoms of a See also:

• BENZENE, C6H6

benzene See also:

• NUCLEUS (Lat. for the kernal of a nut, nux, the stone of fruit)

nucleus are replaced by two See also:

• OXYGEN (symbol 0, atomic weight 16)

oxygen atoms . This replacement may take See also:

• PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place either in the ortho or See also:

• PARA
• PARA (officially BELEM; sometimes BELEM DO PARA)

para positions, giving rise to orthoquinones or to paraquinones; metaquinones do not appear to have been isolated . The para or true quinones are obtained by the oxidation of See also:

• HYDROCARBONS

hydrocarbons with chromic See also:

• ACID (from the Lat. root ac-, sharp; acere, to be sour)

acid or of various para di-derivatives of benzene with chromic acid mixture, such, for example, as para-aminophenol, para-phenylene diamine, paraaminoazobenzene, &c . H. v . Pechmann (Ber., 1888, 21, p .