Binary compounds nomenclature (part 2)

Hydroxide, cyanide, tiocyanate

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).

lithium hydroxide

LiOH

sodium hydroxide

NaOH

potassium hydroxide

KOH

caesium hydroxide

CsOH

magnesium hydroxide

Mg(OH)₂

calcium hydroxide

Ca(OH)₂

barium hydroxide

Ba(OH)₂

aluminium hydroxide

Al(OH)₃

germanium hydroxide

Ge(OH)₄

iron(II) hydroxide

Fe(OH)₂

iron(III) hydroxide

Fe(OH)₃

potassium cyanide

KCN

calcium cyanide

Ca(CN)₂

potassium thiocyanate

KSCN

ammonium thiocyanate

NH₄SCN

sodium thiocyanate

NaSCN

mercury(II) thiocyanate

Hg(SCN)₂