def bC_K_HSO4_HMW84(T, P):
    """c-a: potassium bisulfate [HMW84]."""
    b0 = -0.0003
    b1 = 0.1735
    b2 = 0.0
    C0 = 0
    C1 = 0
    alph1 = 2
    alph2 = -9
    omega = -9
    valid = T == 298.15
    return b0, b1, b2, C0, C1, alph1, alph2, omega, valid
