elements

type Element struct {
	Symbol  string    // Symbol, e.g. "Na"
	Name    string    // Full name, e.g. sodium
	Number  int       // Atomic number e.g. 11
	Isotope []Isotope // Isotope masses and abundances, e.g. {22.989770,1}
}

type Elems struct {
	Elements  []Element
	SymbolMap map[string]int
}

type Isotope struct {
	Mass      float64 // Mass in Daltons
	Abundance float64 // Abundance (fraction)
}