# Question #60254

Mar 19, 2014

Binary compounds contain two elements, thus the prefix 'bi'.

Binary Ionic compound contain a metal and a non-metal. While molecular (covalent) compounds contain two non-metals.

For ionic compounds the metal always keeps its name while the non-metal will keep the root of the element with the suffix -ide.

Examples

NaCl
Na = sodium Cl = chlorine
Keep the metal name sodium, take the root of chlor and add -ide.
sodium Chloride

$C a {F}_{2}$
Ca = calcium F = fluorine
Keep the metal name calcium, take the root fluor and add -ide.
calcium fluoride

For molecular (covalent) compounds the number of atoms in each molecule is identified by a prefix in the name. The second element will always end in the suffix -ide.

mono =1
di = 2
tri = 3
tetra = 4
penta = 5
hexa = 6
hepta = 7
octa = 8
nona = 9
deca = 10

Never use mono with the first element.

Examples

$C {O}_{2}$
C = carbon O = oxygen = oxide
carbon dioxide

${N}_{3} C {l}_{5}$
N = nItrogen Cl = chlorine = chloride
trinitrogen pentachloride

${P}_{4} {O}_{5}$
P = phosphorus O = oxygen = oxide
tetraphosphorus pentoxide
(drop the a from the prefix when using oxide)