There is no "formula" for "calcium and phosphorus".
The symbol for calcium is Ca; the symbol for phosphorus is P.
You'd have to specify an actual compound in order to get a formula.
The chemical formula for Calcium phosphate is Ca3(PO4)2.
Calcium is Ca. Phosphorous acid would be H3PO3. However, the name "calcium phosphorous acid" taken as a whole makes no sense. and if "phosphorus acid" was not a simple misspelling, THAT name makes no sense either.
The chemical formula for boron is B, while the chemical formula for phosphorus is P.
The chemical formula for phosphorus acid is H3PO3.
The chemical formula for phosphorus hydrogen is PH3.
The chemical formula for Calcium phosphate is Ca3(PO4)2.
Ca3P2
Calcium is Ca. Phosphorous acid would be H3PO3. However, the name "calcium phosphorous acid" taken as a whole makes no sense. and if "phosphorus acid" was not a simple misspelling, THAT name makes no sense either.
The chemical formula for Calcium Phosphorus is Ca10(PO4)6(OH)2. It is commonly called hydroxyapatite and is the majority of what comprises bone and dental enamel and dentin.
The chemical formula for phosphorus mononitride is PN.
The chemical formula for boron is B, while the chemical formula for phosphorus is P.
The chemical formula for phosphorus acid is H3PO3.
The chemical formula for Phosphorus Difluorochloride is PF2Cl.
The chemical formula for phosphorus trifluoride is PF3.
The chemical formula for phosphorus pentiodide is PI5.
The chemical formula for phosphorus triiodide is PI3.
The chemical formula for phosphorus hydrogen is PH3.