Mg2(SO4)2
There is no 'binary formula'. You can say that hydrogen iodide is a binary compound, that is one formed from just two elements. HI is its formula.
Formula: CrP
The chemical formula for calcium phosphide is Ca3P2
The formula for magnesium selenide is MgSe. It is a compound that is brown in color and it is a crystalline solid.
Formula: P3-
Formula: P3-
Formula: P3-
Formula: P3-
Mg2+
The formula and charge for the carbonate ion is CO32- and the formula and charge of the magnesium ion is Mg2+. Together they make magnesium carbonate, MgCO3.
Formula: P3-
Mg3P2. It would be called magnesium phosphide.
Ag3P
Formula: P3-
The formula and charge of the nitrate ion is NO3-, and the formula and charge of the magnesium ion is Mg2+. Together they make magnesium nitrate, Mg(NO3)2.
Mg2+