Binary compounds nomenclature (part 1)

Oxide, peroxide,superoxide, sulfide, fluoride, chloride, bromide, iodide

Binary ionic compounds (Group 1, 2, 13 (Al only) metal ions with non-metal ions)

Prototypical Example: Sodium sulfide (Na₂S).

1) Order of Naming: The cation (positive ion) is named first, followed by the anion (negative ion).

2) Naming the Cation: A monatomic cation (single-atom ion) is named the same as the element. For example, Na⁺ is called "sodium" in compounds like Na₂S.

3) Naming the Anion: A monatomic anion is named by taking the root of the element’s name and adding the suffix "-ide." For example, Cl⁻ becomes "chloride," S²⁻ becomes "sulfide," and O²⁻ becomes "oxide."

Binary ionic compounds (Transition metal ions plus Group 13 - 16 metals with non-metal ions)

Prototypical Example: Iron(II) chloride (FeCl₂).

1) Order of Naming: The cation is always named first, followed by the anion.

2) Naming the Cation: A monatomic cation takes the element’s name. Transition metals often have multiple charges, so the charge is indicated by a Roman numeral in parentheses. For example, Cu⁺ is called "copper(I)," and Cu²⁺ is called "copper(II)."

3) Indicating Charge for Transition Metals: Transition metals (except Zn²⁺, Cd²⁺, and Ag⁺, which always have fixed charges) require the charge to be specified in parentheses after the name. Examples include Iron(III), Copper(I), and Vanadium(V).

Non-Transition Metals in Groups 13-16: Some metals in these groups, such as tin (Sn), lead (Pb), and bismuth (Bi), also have multiple charges. In these cases, the charge must be indicated with a Roman numeral after the element’s name. For instance, Pb²⁺ is named "lead(II)." The exception is aluminum (Al), which always has a +3 charge and does not need a Roman numeral.

Binary covalent compounds (Non-metal atoms with non-metal atoms (covalent compounds))

Prototypical Example: Carbon dioxide (CO₂).

1) Order of Naming: The first element in the formula is named as the element itself (e.g., "carbon" in CO₂).

2) Naming the Second Element: The second element is named like an anion, with the suffix "-ide" added (e.g., "oxide" in CO₂).

3) Prefixes for Quantity of the Second Element: A prefix is used to indicate the number of atoms of the second element (e.g., "di-" in "dioxide" because there are two oxygen atoms). The second element only gets a prefix if more than one atom is present. For example, CO₂ is "carbon dioxide," while CO would be "carbon monoxide" (with the "mono-" prefix for one oxygen atom). Prefixes such as "di," "tri," or "tetra" are used for multiple atoms, and the final "a" or "o" of the prefix is typically dropped if the element name begins with a vowel (e.g., "tetroxide" instead of "tetraoxide" for four oxygen atoms).

carbon monoxide

CO

carbon dioxide

CO₂

potassium oxide

K₂O

silicon dioxide

SiO₂

nitrogen monoxide

NO

nitrogen dioxide

NO₂

dinitrogen monoxide

N₂O

Dinitrogen tetroxide

N₂O₄

scandium oxide

Sc₂O₃

copper(I) oxide

Cu₂O

mercury(I) oxide

Hg₂O

mercury(II) oxide

HgO

zinc(II) oxide

ZnO

calcium oxide

CaO

zirconium(IV) oxide

ZrO₂

niobium(V) oxide

Nb₂O₅

molybdenum(VI) oxide

MoO₃

tungsten(VI) oxide

WO₃

ruthenium(VIII) oxide

RuO₄

osmium(VIII) oxide

OsO₄

iridium(VIII) oxide

IrO₄

sodium peroxide

Na₂O₂

potassium superoxide

KO₂

potassium ozonide

KO₃

hydrogen peroxide

H₂O₂

vanadium(V) sulfide

V₂S₅

iron(II) sulfide

FeS

iron(III) sulfide

Fe₂S₃

potassium sulfide

K₂S

diphosphorus pentasulfide

P₂S₅

mercury(II) sulfide

HgS

sulfur tetrafluoride

SF₄

disulfur difluoride

S₂F₂

disulfur decafluoride

S₂F₁₀

chromium(VI) fluoride

CrF₆

phosphorus trifluoride

PF₃

rhodium(III) chloride

RhCl₃

silver chloride

AgCl

technetium(VII) chloride

TcCl₇

rhenium(VII) chloride

ReCl₇

iron(II) chloride

FeCl₂

iron(III) chloride

FeCl₃

nickel(II) chloride

NiCl₂

cadmium chloride

CdCl₂

palladium(II) chloride

PdCl₂

platinum(IV) chloride

PtCl₄

carbon tetrachloride

CCl₄

chromium(III) chloride

CrCl₃

gold(III) chloride

AuCl₃

Mercury(II) chloride

HgCl₂

Mercury(I) chloride

Hg₂Cl₂

sodium bromide

NaBr

calcium bromide

CaBr₂

diselenium dibromide

Se₂Br₂

iodine pentabromide

IBr₅

lithium iodide

LiI

ammonium sulfide

(NH₄)₂S

ammonium chloride

NH₄Cl