any of the bivalent metals of group II of the periodic table (calcium or strontium or barium or magnesium or beryllium)

any of the bivalent metals of group II of the periodic table (calcium or strontium or barium or magnesium or beryllium)

any of the bivalent metals of group II of the periodic table (calcium or strontium or barium or magnesium or beryllium)

any of the bivalent metals of group II of the periodic table (calcium or strontium or barium or magnesium or beryllium)

any of the bivalent metals of group II of the periodic table (calcium or strontium or barium or magnesium or beryllium)

any of the bivalent metals of group II of the periodic table (calcium or strontium or barium or magnesium or beryllium)

any of the bivalent metals of group II of the periodic table (calcium or strontium or barium or magnesium or beryllium)