1.   Amid the phosphate grains, they said, scientists also have found calcium compounds that filter phosphorus from water.

2.   Marine animals with calcium carbonate shells or skeletons build them from carbon dioxide and dissolved calcium compounds.

3.   Shober had learned from her husband, an engineer with the Wisconsin Transportation Department, that rock salt is a calcium compound.

4.   Many doctors have told such patients to cut down on calcium because most kidney stones are made of a calcium compound.