sn has either 2 or 4; P has 3 or 5. It usually varies by two for a given element, as though a pair of bonds sometimes saturated each other;.
"An Introduction to Chemical Science"
R.P. Williams
Solder may have two parts of sn to one of Pb, two of Pb to one of sn, or equal parts of each, or the two elements may alloy in other proportions.
"An Introduction to Chemical Science"
R.P. Williams
sn, Pb, and Zn are somewhat soluble in vegetable acids.
"An Introduction to Chemical Science"
R.P. Williams
