2CaCl22 \mathrm{CaCl}_{2}2CaCl2
Ca(OCl)Cl\mathrm {Ca(OCl)Cl}Ca(OCl)Cl
2CHCl32 \mathrm{CHCl}_{3}2CHCl3
CH3CH2OH\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}CH3CH2OH