Transition Metals With Polyatomic Ions

The formula for mercury(I) chloride is Hg2Cl2. Unlike other transition metals, the 1+ cation of mercury has the formula Hg22+ and behaves like a polyatomic ion.

The formula for mercury(II) nitride is Hg3N2. Mercury has a 2+ charge, as indicated by the roman numeral, and nitride has a 3- charge. Three mercury ions and two nitride ions are needed to balance the charges between the cation and anion.

Tin(IV) chloride is the name for the compound with the formula SnCl4. The roman numeral must be included in the name because tin has two possible charges, 2+ and 4+. The formula has four chloride ions, each with a 1- charge, so the charge on tin must be 4+ to balance the charges between the cation and anions.

Scandium perchlorate is the name for the compound with the formula Sc(ClO4)3. A roman numeral is not included in the name because scandium has only one possible charge, 3+.

Tin(IV) chromate is the name for the compound with the formula Sn(CrO4)2. With two chromate ions, each with a 2- charge, the charge on tin must be 4+ to balance the charges between the cation and anion. Tin cations can have a 2+ or 4+ charge, so a roman numeral must be included in the name.

The name for the compound with the formula SnSO4 is tin(II) sulfate. Sulfate has a 2- charge. The magnitude of the charge on tin must match that of sulfate since the formula includes one tin ion and one sulfate ion. Tin has two possible charges, 2+ and 4+, so a roman numeral must be used in the name to indicate which one.

In chromium(II) nitrate, there is one chromium ion in the formula. Chromium has a 2+ charge and nitrate has a 1- charge, so one chromium ion and two nitrate ions are in the formula to create a balance between the charges of the cation and the anion.

Chromium(II) hydroxide has the formula Cr(OH)2. Chromium has a 2+ charge and the hydroxide ion has a 1- charge, so two anions are needed to balance the charge of the cation.

The formula for cobalt(II) chloride is CoCl2 so there are 2 chloride ions in the compound. Cobalt has a 2+ charge, so two chloride ions, each with a 1- charge, are needed to balance the cation's charge.

The formula for copper(I) sulfate is Cu2SO4, so the copper-to-sulfate ratio is 2:1. The sulfate has a 2- charge, so two Cu+ ions are needed to balance the charge.

The name for the compound with the formula Pb(SO3)2 is lead(IV) sulfite. Since there are two sulfite ions, each with a 2- charge, the charge on lead must be 4+. Lead can have a 2+ or 4+ charge, so a roman numeral is needed to indicate the charge on the cation.

Iron(II) phosphite has the formula Fe3(PO3)2. The roman numeral in the name indicates that the iron has a 2+ charge. Phosphite has a 3- charge (PO33-). Three iron cations and two phosphite ions in the compound balance the charges between the cation and anion.

The name for the compound with the formula CoP is cobalt(III) phosphide. Cobalt has two possible charges, 2+ and 3+, so a roman numeral should be included in the name to represent the charge of the cation in this compound.

The cobalt in CoBr2 has a charge of 2+. Cobalt is a transition metal, so it forms a cation with a positive charge. The bromide ion has a 1- charge, so if two are needed to balance the charge of the cobalt, then cobalt must have a 2+ charge.

The name for the compound with the formula PbF2 is lead(II) fluoride. Lead cations can have more than one charge (2+ or 4+), so a roman numeral should be included in the name. Fluoride has a 1- charge and if two anions are needed to balance the charge on the lead cation, then it must have a 2+ charge.

Zinc dichromate has the formula ZnCr2O7. Zinc chloride would have the formula ZnCl2. Zinc has only one possible charge (2+), so roman numerals are not needed in the name for zinc compounds.

The formula for chromium(III) sulfide is Cr2S3. Chromium has a 3+ charge as indicated by the roman numeral in the name. Sulfide anions have a 2- charge. To balance the charges between the cations and anions, two chromium ions and three sulfide ions are needed.

The formula for cobalt(III) chlorate is Co(ClO3)3. Cobalt has a 3+ charge, so three chlorate anions (ClO3¯) are needed to balance the charge of the cobalt.

Copper(I) nitride has the formula Cu3N. Since copper has a 1+ charge and the nitride anion has a 3- charge, three copper ions are needed to balance the charge of the nitride ion.

The charge on the silver ion in AgMnO4 is 1+ because it has only one possible charge, 1+. The permanganate ion, MnO4¯, has a 1- charge, so a compound with a 1:1 ratio will have the same magnitude of charge on both ions. The cation is written first in the formula and in the name.

Lead(II) cyanide has the formula Pb(CN)2. The cyanide ion has a 1- charge, and if two anions are needed to balance the charge from the cation, then lead must have a 2+ charge. The roman numeral in the compound's name indicates the charge on the lead cation.

Zinc iodide has the formula ZnI2 because zinc has a 2+ charge and iodide has a 1- charge. Therefore, two iodide ions are needed to balance the charge of the zinc cation. A roman numeral is not needed in the name because zinc only has one possible charge.

The copper ion in CuF2 has a 2+ charge. The compound has two fluoride ions, each with a 1- charge; therefore copper must have a 2+ charge to balance the charges between the cation and anion.

Cr(OH)3 is the formula for chromium(III) hydroxide. AgOH is silver hydroxide. Silver has only one possible charge, 1+, so a roman numeral should not be included in the name.

The name for the compound with the formula Ag2CO3 is silver carbonate. Silver has only one possible charge (1+), so no roman numeral should be used in the name.

The iron cation in Fe2S3 has a 3+ charge. Based on the formula, there are two iron cations and three sulfide ions. Each sulfide ion has a 2- charge, so if there are three sulfide ions, the two iron cations must have a total charge of 6+ or 3+ on each cation.

In copper(II) phosphide, the copper ion has a 2+ charge and the phosphide ion has a 3- charge. The cation is listed first in the name for the compound so the copper must have a positive charge. The roman numeral listed after copper indicates that the copper will have a 2+ charge.

Iron(II) oxide is the name for the compound with the formula FeO. Since iron is a transition metal and can have multiple charges (2+ and 3+), the roman numeral is needed to indicate its charge. The formula has a 1:1 ratio between the cation and anion, so the charge on the iron must be the same magnitude, but the opposite sign, for the oxide anion (2-).

The formula for iron(III) sulfite is Fe2(SO3)3. As indicated by the roman numeral, iron has a charge of 3+. Sulfite has a 2- charge, requiring three sulfite ions and two iron ions to create a balance of charges between the cation and anions.