pub(crate) const ATOMIC_MASS: [f64; 118] = [
1.0078, 4.0026, 6.94, 9.0122, 10.81, 12.011, 14.007, 15.999, 18.9984, 20.1797, 22.9898, 24.305, 26.9815, 28.085, 30.9738, 32.06, 35.453, 39.948, 39.0983, 40.078, 44.9559, 47.867, 50.9415, 51.996, 54.938, 55.845, 58.9332, 58.6934, 63.546, 65.38, 69.72, 72.63, 74.9216, 78.971, 79.904, 83.798, 85.4678, 87.62, 88.9058, 91.224, 92.9064, 95.95, 97.907, 101.07, 102.906, 106.42, 107.868, 112.414, 114.818, 118.71, 121.76, 127.6, 126.905, 131.293, 132.905, 137.327, 138.905, 140.116, 140.908, 144.242, 145.0, 150.36, 151.96, 157.25, 158.925, 162.5, 164.93, 167.259, 168.934, 173.045, 174.967, 178.49, 180.948, 183.84, 186.207, 190.23, 192.217, 195.084, 196.967, 200.592, 204.383, 207.2, 208.98, 209.0, 210.0, 222.0, 223.0, 226.0, 227.0, 232.038, 231.036, 238.029, 237.048, 239.052, 243.0, 247.0, 247.0, 251.0, 252.0, 257.0, 258.0, 259.0, 266.0, 267.0, 268.0, 269.0, 270.0, 269.0, 278.0, 281.0, 282.0, 285.0, 286.0, 289.0, 290.0, 293.0, 294.0, 294.0, ];
pub fn atomic_mass(iz: i64) -> Option<f64> {
if iz >= 1 && iz as usize <= ATOMIC_MASS.len() {
Some(ATOMIC_MASS[(iz - 1) as usize])
} else {
None
}
}