Multiplicative prefixes indicate the number of atoms of each element: mono-, di-, tri-, tetra-, penta-, hexa-, etc.
Examples:
C₂H₂: dihydride dicarbon (a covalent compound — prefixes describe atom counts)
AlH₃: aluminum trihydride (alane)
LiH: lithium hydride
CaH₂: calcium dihydride (calcium hydride)
Nomenclature by oxidation state
When hydrogen is more electronegative (as in hydracids) it is assigned +1; in metal hydrides hydrogen is commonly assigned -1. The oxidation state of the other element is indicated using Roman numerals or numbers in parentheses.
To determine the oxidation state, multiply the hydrogen charge (-1 in metal hydrides) by the number of hydrogens to obtain the total negative charge. That is balanced by the positive charge of the other element; divide by the number of atoms of that element to get its oxidation state.
Elements that typically have a single oxidation state (alkali metals +1, alkaline earth metals +2, aluminum +3) commonly omit the oxidation state in their names.
Examples:
FeH₂: iron(II) hydride
AlH₃: aluminum hydride (alane)
LiH: lithium hydride
Nomenclature with suffix -ane
Hydrides of nonmetals that complete the valence shell can be named with the -ane suffix (analogous to organic -ane names).
Examples:
CH₄: methane
SiH₄: silane
GeH₄: germane
PH₃: phosphine (also called phosphane)
Hydracids (aqueous hydrides)
Hydrides of group 16 and 17 elements form acids when dissolved in water; these are called hydracids. Their aqueous state is indicated with (aq) or (ac).
Because the nonmetal is more electronegative than hydrogen, in these acids hydrogen is assigned +1 and appears at the beginning of the formula.
Names use the word "acid" followed by the nonmetal name with the suffix "-hydric" in many languages; in English we use e.g. "hydrochloric acid" for HCl(aq).
Examples:
HCl(aq): hydrochloric acid
HBr(aq): hydrobromic acid
HI(aq): hydroiodic acid
H₂S(aq): hydrosulfuric acid (hydrogen sulfide in water)
These substances are named differently in the gas phase:
HCl(g): hydrogen chloride
HBr(g): hydrogen bromide
H₂S(g): hydrogen sulfide
1. Name <b>AlH₃</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Aluminum hydride (AlH₃, alane) is a white solid that reacts violently with water. It is used as a reducing agent in organic chemistry and as a hydrogen source; it decomposes releasing hydrogen.
2. Name <b>FeH₂</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Iron(II) hydride (FeH2) is typically unstable under normal conditions and decomposes readily. Iron hydrides are relevant in catalysis and the study of hydrogen embrittlement in steels.
3. Name <b>FeH₃</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Iron(III) hydride (FeH3) is extremely unstable and exists only under specialized laboratory conditions; it helps study coordination chemistry and hydrogen storage mechanisms.
4. Name <b>CaH₂</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Calcium hydride (CaH2) is a strong desiccant used in laboratories. It reacts with water to produce calcium hydroxide and hydrogen gas, and is used as a portable hydrogen source and a deoxidizer in metallurgy.
5. Name <b>SnH₄</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Tin(IV) hydride (stannane, SnH₄) is a colorless, toxic gas unstable at room temperature. It is used in chemical vapor deposition to make thin tin films and in organotin synthesis.
6. Name <b>HgH₂</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Mercury(II) hydride (HgH2) is extremely unstable and decomposes to mercury and hydrogen; mercury compounds are highly toxic and handled only for academic study.
7. Name <b>N₂H₂</b>:
(1 point)
a
)
By prefixes (oxidation state not usually used)
Feedback: Dinitrogen dihydride (N₂H₂, diimide) is an unstable intermediate used as a reducing agent in organic synthesis; it can hydrogenate alkenes selectively.
8. Name <b>PH₃</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Phosphine (PH₃) is a colorless, flammable, and highly toxic gas with a fishy or garlic odor. It is used as a fumigant, as a dopant precursor in semiconductor industry, and as a synthetic intermediate.
9. Name <b>BeH₂</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Beryllium hydride (BeH2) is a white polymeric solid with high hydrogen content; it has been studied for hydrogen storage. Beryllium compounds are highly toxic.
10. Name <b>BiH₃</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Bismuth hydride (BiH₃) is a colorless, highly unstable, and toxic gas that decomposes to bismuth and hydrogen; it is mainly of academic interest and a precursor in some thin-film processes.
11. Name <b>ZnH₂</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Zinc hydride (ZnH2) is a white powder that decomposes slowly and acts as a strong reducing agent; it has been studied for hydrogenation catalysis and hydrogen storage.
12. Name <b>AsH₃</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Arsine (AsH₃) is a colorless, extremely toxic gas with a garlic-like odor. It is used as a dopant precursor in semiconductor manufacturing and as an intermediate in certain syntheses.
13. Name <b>SiH₄</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Silane (SiH₄) is a colorless, pyrophoric gas that ignites spontaneously in air. It is widely used in the electronics industry for semiconductor and solar-cell production and as a precursor in CVD processes.
14. Name <b>LiH</b>:
(2 points)
a
)
By oxidation state
b
)
By prefixes
Feedback: Lithium hydride (LiH) is a white crystalline solid used as a hydrogen source and a strong reducing agent in organic synthesis; it also finds niche uses in aerospace thermal shielding and hydrogen storage research.
15. Formula los hidruros:
(15 points)
a
)
Sodium hydride
b
)
Barium hydride
c
)
Tin(IV) hydride
d
)
Antimony trihydride
e
)
Potassium hydride
f
)
Mercury(II) hydride
g
)
Dinitrogen dihydride
h
)
Magnesium hydride
i
)
Tin(II) hydride
j
)
Calcium hydride
k
)
Mercury dihydride
l
)
Mercury(I) hydride
m
)
Phosphorus pentahydride (rare)
n
)
Arsenic pentahydride (rare)
o
)
Arsine
Feedback:
16. Name or write the formulas for the hydrides with the suffix -ane:
(4 points)
a
)
Silane
b
)
Phosphine
c
)
Methane
d
)
Borane
Feedback:
17. Name or write the formulas for the hydrides in aqueous solution (hydracids):
(4 points)