{
    "_comment":  "Initial molar fractions for the extended chemical model", 
    "x_{CO2, w}":  3.9624e-10, 
    "x_{Ca^{2+}, w}":  2.1703e-06,
    "x_{H+, w}": 2.3507e-12,
    "x_{OH^-, w}":  1.5475e-06,
    "x_{HCO3^-, w}": 1.5467e-06,
    "x_{CO3^{-2}, w}": 6.2315e-07
}