Hydrogen chloride - Misplaced Pages

The compound hydrogen chloride has the chemical formula HCl and as such is a hydrogen halide. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride gas and hydrochloric acid are important in technology and industry. Hydrochloric acid, the aqueous solution of hydrogen chloride, is also commonly given the formula HCl.

Reactions

Hydrogen chloride is a diatomic molecule, consisting of a hydrogen atom H and a chlorine atom Cl connected by a polar covalent bond. The chlorine atom is much more electronegative than the hydrogen atom, which makes this bond polar. Consequently, the molecule has a large dipole moment with a negative partial charge (δ−) at the chlorine atom and a positive partial charge (δ+) at the hydrogen atom. In part because of its high polarity, HCl is very soluble in water (and in other polar solvents).

Upon contact, H₂O and HCl combine to form hydronium cations [H₃O] and chloride anions Cl through a reversible chemical reaction:

HCl + H₂O → [H₃O] + Cl

The resulting solution is called hydrochloric acid and is a strong acid. The acid dissociation or ionization constant, K_a, is large, which means HCl dissociates or ionizes practically completely in water. Even in the absence of water, hydrogen chloride can still act as an acid. For example, hydrogen chloride can dissolve in certain other solvents such as methanol:

HCl + CH₃OH → [CH₃OH₂] + Cl

Hydrogen chloride can protonate molecules or ions and can also serve as an acid-catalyst for chemical reactions where anhydrous (water-free) conditions are desired.

Because of its acidic nature, hydrogen chloride is a corrosive substance, particularly in the presence of moisture.

Structure and properties

The structure of solid DCl, as determined by neutron diffraction of DCl powder at 77 K. DCl was used instead of HCl because the deuterium nucleus is easier to detect than the hydrogen nucleus. The extended linear structure is indicated by the dashed lines.

Frozen HCl undergoes a phase transition at 98.4 K (−174.8 °C; −282.5 °F). X-ray powder diffraction of the frozen material shows that the material changes from an orthorhombic structure to a cubic one during this transition. In both structures the chlorine atoms are in a face-centered array. However, the hydrogen atoms could not be located. Analysis of spectroscopic and dielectric data, and determination of the structure of DCl (deuterium chloride) indicates that HCl forms zigzag chains in the solid, as does HF (see figure on right).

Solubility of HCl (g/L) in common solvents
Temperature (°C)	0	20	30	50
Water	823	720	673	596
Methanol	513	470	430
Ethanol	454	410	381
Ether	356	249	195

One doublet in the IR spectrum resulting from the isotopic composition of chlorine

The infrared spectrum of gaseous hydrogen chloride, shown on the left, consists of a number of sharp absorption lines grouped around 2886 cm (wavelength ~3.47 μm). At room temperature, almost all molecules are in the ground vibrational state v = 0. Including anharmonicity the vibrational energy can be written as:

E_{\mathrm {v} }=h\nu _{e}\left(v+{\tfrac {1}{2}}\right)+hx_{e}\nu _{e}\left(v+{\tfrac {1}{2}}\right)^{2}

To promote an HCl molecule from the v = 0 to the v = 1 state, we would expect to see an infrared absorption about ν_o = ν_e + 2x_eν_e = 2880 cm. However, this absorption corresponding to the Q-branch is not observed due to it being forbidden by symmetry. Instead, two sets of signals (P- and R-branches) are seen owing to a simultaneous change in the rotational state of the molecules. Because of quantum mechanical selection rules, only certain rotational transitions are permitted. The states are characterized by the rotational quantum number J = 0, 1, 2, 3, ... selection rules state that ΔJ is only able to take values of ±1.

E(J)_{\mathrm {rot} }=h\cdot B\cdot J(J+1)

The value of the rotational constant B is much smaller than the vibrational one ν_o, such that a much smaller amount of energy is required to rotate the molecule; for a typical molecule, this lies within the microwave region. However, the vibrational energy of HCl molecule places its absorptions within the infrared region, allowing a spectrum showing the rovibrational transitions of this molecule to be easily collected using an infrared spectrometer with a gas cell. The latter can even be made of quartz as the HCl absorption lies in a window of transparency for this material.

Naturally abundant chlorine consists of two isotopes, Cl and Cl, in a ratio of approximately 3:1. While the spring constants are nearly identical, the disparate reduced masses of HCl and HCl cause measurable differences in the rotational energy, thus doublets are observed on close inspection of each absorption line, weighted in the same ratio of 3:1.

Production

Most hydrogen chloride produced on an industrial scale is used for hydrochloric acid production.

Historical routes

In the 17th century, Johann Rudolf Glauber from Karlstadt am Main, Germany used sodium chloride salt and sulfuric acid for the preparation of sodium sulfate in the Mannheim process, releasing hydrogen chloride. Joseph Priestley of Leeds, England prepared pure hydrogen chloride in 1772, and by 1808 Humphry Davy of Penzance, England had proved that the chemical composition included hydrogen and chlorine.

Direct synthesis

Flame inside HCl oven

Hydrogen chloride is produced by combining chlorine and hydrogen:

Cl₂ + H₂ → 2 HCl

As the reaction is exothermic, the installation is called an HCl oven or HCl burner. The resulting hydrogen chloride gas is absorbed in deionized water, resulting in chemically pure hydrochloric acid. This reaction can give a very pure product, e.g. for use in the food industry.

The reaction can also be triggered by blue light.

Organic synthesis

The industrial production of hydrogen chloride is often integrated with the formation of chlorinated and fluorinated organic compounds, e.g., Teflon, Freon, and other CFCs, as well as chloroacetic acid and PVC. Often this production of hydrochloric acid is integrated with captive use of it on-site. In the chemical reactions, hydrogen atoms on the hydrocarbon are replaced by chlorine atoms, whereupon the released hydrogen atom recombines with the spare atom from the chlorine molecule, forming hydrogen chloride. Fluorination is a subsequent chlorine-replacement reaction, producing again hydrogen chloride:

RH + Cl₂ → RCl + HCl

RCl + HF → RF + HCl

The resulting hydrogen chloride is either reused directly or absorbed in water, resulting in hydrochloric acid of technical or industrial grade.

Laboratory methods

Small amounts of hydrogen chloride for laboratory use can be generated in an HCl generator by dehydrating hydrochloric acid with either sulfuric acid or anhydrous calcium chloride. Alternatively, HCl can be generated by the reaction of sulfuric acid with sodium chloride:

NaCl + H₂SO₄ → NaHSO₄ + HCl↑

This reaction occurs at room temperature. Provided there is NaCl remaining in the generator and it is heated above 200 °C, the reaction proceeds further:

NaCl + NaHSO₄ → Na₂SO₄ + HCl↑

For such generators to function, the reagents should be dry.

Hydrogen chloride can also be prepared by the hydrolysis of certain reactive chloride compounds such as phosphorus chlorides, thionyl chloride (SOCl₂), and acyl chlorides. For example, cold water can be gradually dripped onto phosphorus pentachloride (PCl₅) to give HCl:

PCl₅ + H₂O → POCl₃ + 2 HCl↑

Applications

Most hydrogen chloride is consumed in the production of hydrochloric acid. It is also used in the production of vinyl chloride and many alkyl chlorides. Trichlorosilane, a precursor to ultrapure silicon, is produced by the reaction of hydrogen chloride and silicon at around 300 °C.

Si + 3 HCl → HSiCl₃ + H₂

History

Around 900, the authors of the Arabic writings attributed to Jabir ibn Hayyan (Latin: Geber) and the Persian physician and alchemist Abu Bakr al-Razi (c. 865–925, Latin: Rhazes) were experimenting with sal ammoniac (ammonium chloride), which when it was distilled together with vitriol (hydrated sulfates of various metals) produced hydrogen chloride. It is possible that in one of his experiments, al-Razi stumbled upon a primitive method to produce hydrochloric acid. However, it appears that in most of these early experiments with chloride salts, the gaseous products were discarded, and hydrogen chloride may have been produced many times before it was discovered that it can be put to chemical use.

One of the first such uses was the synthesis of mercury(II) chloride (corrosive sublimate), whose production from the heating of mercury either with alum and ammonium chloride or with vitriol and sodium chloride was first described in the De aluminibus et salibus ("On Alums and Salts"), an eleventh- or twelfth century Arabic text falsely attributed to Abu Bakr al-Razi and translated into Latin by Gerard of Cremona (1144–1187).

Another important development was the discovery by pseudo-Geber (in the De inventione veritatis, "On the Discovery of Truth", after c. 1300) that by adding ammonium chloride to nitric acid, a strong solvent capable of dissolving gold (i.e., aqua regia) could be produced.

After the discovery in the late sixteenth century of the process by which unmixed hydrochloric acid can be prepared, it was recognized that this new acid (then known as spirit of salt or acidum salis) released vaporous hydrogen chloride, which was called marine acid air. In the 17th century, Johann Rudolf Glauber used salt (sodium chloride) and sulfuric acid for the preparation of sodium sulfate, releasing hydrogen chloride gas (see production, above). In 1772, Carl Wilhelm Scheele also reported this reaction and is sometimes credited with its discovery. Joseph Priestley prepared hydrogen chloride in 1772, and in 1810 Humphry Davy established that it is composed of hydrogen and chlorine.

During the Industrial Revolution, demand for alkaline substances such as soda ash increased, and Nicolas Leblanc developed a new industrial-scale process for producing the soda ash. In the Leblanc process, salt was converted to soda ash, using sulfuric acid, limestone, and coal, giving hydrogen chloride as by-product. Initially, this gas was vented to air, but the Alkali Act of 1863 prohibited such release, so then soda ash producers absorbed the HCl waste gas in water, producing hydrochloric acid on an industrial scale. Later, the Hargreaves process was developed, which is similar to the Leblanc process except sulfur dioxide, water, and air are used instead of sulfuric acid in a reaction which is exothermic overall. In the early 20th century the Leblanc process was effectively replaced by the Solvay process, which did not produce HCl. However, hydrogen chloride production continued as a step in hydrochloric acid production.

Historical uses of hydrogen chloride in the 20th century include hydrochlorinations of alkynes in producing the chlorinated monomers chloroprene and vinyl chloride, which are subsequently polymerized to make polychloroprene (Neoprene) and polyvinyl chloride (PVC), respectively. In the production of vinyl chloride, acetylene (C₂H₂) is hydrochlorinated by adding the HCl across the triple bond of the C₂H₂ molecule, turning the triple into a double bond, yielding vinyl chloride.

The "acetylene process", used until the 1960s for making chloroprene, starts out by joining two acetylene molecules, and then adds HCl to the joined intermediate across the triple bond to convert it to chloroprene as shown here:

This "acetylene process" has been replaced by a process which adds Cl₂ to the double bond of ethylene instead, and subsequent elimination produces HCl instead, as well as chloroprene.

Safety

Hydrogen chloride forms corrosive hydrochloric acid on contact with water found in body tissue. Inhalation of the fumes can cause coughing, choking, inflammation of the nose, throat, and upper respiratory tract, and in severe cases, pulmonary edema, circulatory system failure, and death. Skin contact can cause redness, pain, and severe chemical burns. Hydrogen chloride may cause severe burns to the eye and permanent eye damage.

The U.S. Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health have established occupational exposure limits for hydrogen chloride at a ceiling of 5 ppm (7 mg/m), and compiled extensive information on hydrogen chloride workplace safety concerns.

References

"hydrogen chloride (CHEBI:17883)". Chemical Entities of Biological Interest (ChEBI). UK: European Bioinformatics Institute.
Favre, Henri A.; Powell, Warren H., eds. (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. Cambridge: The Royal Society of Chemistry. p. 131. ISBN 9781849733069.
Haynes, William M. (2010). Handbook of Chemistry and Physics (91 ed.). Boca Raton, Florida, USA: CRC Press. p. 4–67. ISBN 978-1-43982077-3.
Hydrogen Chloride. Gas Encyclopaedia. Air Liquide
Tipping, E.(2002) . Cambridge University Press, 2004.
Trummal, A.; Lipping, L.; Kaljurand, I.; Koppel, I. A.; Leito, I. "Acidity of Strong Acids in Water and Dimethyl Sulfoxide" J. Phys. Chem. A. 2016, 120, 3663-3669. doi:10.1021/acs.jpca.6b02253
^ NIOSH Pocket Guide to Chemical Hazards. "#0332". National Institute for Occupational Safety and Health (NIOSH).
^ "Hydrogen chloride". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
Ouellette, Robert J.; Rawn, J. David (2015). Principles of Organic Chemistry. Elsevier Science. pp. 6–. ISBN 978-0-12-802634-2.
Natta, G. (1933). "Struttura e polimorfismo degli acidi alogenidrici". Gazzetta Chimica Italiana (in Italian). 63: 425–439.
Sándor, E.; Farrow, R. F. C. (1967). "Crystal Structure of Solid Hydrogen Chloride and Deuterium Chloride". Nature. 213 (5072): 171–172. Bibcode:1967Natur.213..171S. doi:10.1038/213171a0. S2CID 4161132.
Hydrochloric Acid – Compound Summary. Pubchem
^ Austin, Severin; Glowacki, Arndt (2000). Hydrochloric Acid. doi:10.1002/14356007.a13_283. ISBN 3527306730.
Priestley J (1772). "Observations on different kinds of air [i.e., gases]". Philosophical Transactions of the Royal Society of London. 62: 147–264 (234–244). doi:10.1098/rstl.1772.0021. S2CID 186210131.
Davy H (1808). "Electro-chemical researches, on the decomposition of the earths; with observations on the metals obtained from the alkaline earths, and on the amalgam procured from ammonia". Philosophical Transactions of the Royal Society of London. 98: 333–370. Bibcode:1808RSPT...98..333D. doi:10.1098/rstl.1808.0023. S2CID 96364168. p. 343: When potassium was heated in muriatic acid gas , as dry as it could be obtained by common chemical means, there was a violent chemical action with ignition; and when the potassium was in sufficient quantity, the muriatic acid gas wholly disappeared, and from one-third to one-fourth of its volume of hydrogene was evolved, and muriate of potash was formed. (The reaction was: 2HCl + 2K → 2KCl + H₂)
Cramer, Chris. Hydrogen Chloride Cannon.
Francisco J. Arnsliz (1995). "A Convenient Way To Generate Hydrogen Chloride in the Freshman Lab". J. Chem. Educ. 72 (12): 1139. Bibcode:1995JChEd..72.1139A. doi:10.1021/ed072p1139. Archived from the original on 24 September 2009. Retrieved 6 May 2009.
Simmler, Walter (2000). "Silicon Compounds, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a24_001. ISBN 978-3-527-30385-4.
Kraus, Paul (1942–1943). Jâbir ibn Hayyân: Contribution à l'histoire des idées scientifiques dans l'Islam. I. Le corpus des écrits jâbiriens. II. Jâbir et la science grecque. Cairo: Institut Français d'Archéologie Orientale. ISBN 9783487091150. OCLC 468740510. vol. II, pp. 41–42; Multhauf, Robert P. (1966). The Origins of Chemistry. London: Oldbourne. pp. 141-142.
Stapleton, Henry E.; Azo, R.F.; Hidayat Husain, M. (1927). "Chemistry in Iraq and Persia in the Tenth Century A.D." Memoirs of the Asiatic Society of Bengal. VIII (6): 317–418. OCLC 706947607. p. 333. The relevant recipe reads as follows: "Take equal parts of sweet salt, Bitter salt, Ṭabarzad salt, Andarānī salt, Indian salt, salt of Al-Qilī, and salt of Urine. After adding an equal weight of good crystallised Sal-ammoniac, dissolve by moisture, and distil (the mixture). There will distil over a strong water, which will cleave stone (sakhr) instantly." (p. 333) For a glossary of the terms used in this recipe, see p. 322. German translation of the same passage in Ruska, Julius (1937). Al-Rāzī's Buch Geheimnis der Geheimnisse. Mit Einleitung und Erläuterungen in deutscher Übersetzung. Quellen und Studien zur Geschichte der Naturwissenschaften und der Medizin. Vol. VI. Berlin: Springer. p. 182, §5. An English translation of Ruska 1937's translation can be found in Taylor, Gail Marlow (2015). The Alchemy of Al-Razi: A Translation of the "Book of Secrets". CreateSpace Independent Publishing Platform. ISBN 9781507778791. pp. 139–140.
Multhauf 1966, p. 142, note 79.
Multhauf 1966, pp. 160–163.
Karpenko, Vladimír; Norris, John A. (2002). "Vitriol in the History of Chemistry". Chemické listy. 96 (12): 997–1005. p. 1002.
Multhauf 1966, p. 208, note 29; cf. p. 142, note 79.
Hartley, Harold (1960). "The Wilkins Lecture. Sir Humphry Davy, Bt., P.R.S. 1778–1829". Proceedings of the Royal Society A. 255 (1281): 153–180. Bibcode:1960RSPSA.255..153H. doi:10.1098/rspa.1960.0060. S2CID 176370921.
Contaminants, National Research Council (US) Committee on Emergency and Continuous Exposure Guidance Levels for Selected Submarine (2009), "Hydrogen Chloride", Emergency and Continuous Exposure Guidance Levels for Selected Submarine Contaminants: Volume 3, National Academies Press (US), retrieved 23 April 2024
CDC – NIOSH Pocket Guide to Chemical Hazards
"Hydrogen Chloride". CDC - NIOSH Workplace Safety and Health Topic. 5 March 2012. Retrieved 15 July 2016.

External links

International Chemical Safety Card 0163
Thames & Kosmos Chem C2000 Experiment Manual

v t e Hydrogen compounds
H₃AsO₃ H₃AsO₄ HArF HAt HSO₃F H[BF₄] HBr HBrO HBrO₂ HBrO₃ HBrO₄ HCl HClO HClO₂ HClO₃ HClO₄ HCN HCNO H₂CrO₄/H₂Cr₂O₇ H₂CO₃ H₂CS₃ HF HFO HI HIO HIO₂ HIO₃ HIO₄ HMnO₄ H₂MnO₄ H₂MoO₄ HNC NaHCO₃ HNCO HNO HNO₂ HNO₃ H₂N₂O₂ HNO₅S H₃NSO₃ H₂O H₂O₂ H₂O₃ H₂O₄ H₂O₅ H₃PO₂ H₃PO₃ H₃PO₄ H₄P₂O₇ H₅P₃O₁₀ H₂[PtCl₆] H₂S H₂S₂ H₂Se H₂SeO₃ H₂SeO₄ H₄SiO₄ H₂[SiF₆] HSCN HNCS H₂SO₃ H₂SO₄ H₂SO₅ H₂S₂O₃ H₃O H₂S₂O₆ H₂S₂O₇ H₂S₂O₈ CF₃SO₃H H₂Te H₂TeO₃ H₆TeO₆ H₄TiO₄ H₂Po H[Co(CO)₄]

Hydrogen compounds

Molecules detected in outer space

Molecules

Diatomic	Aluminium monochloride Aluminium monofluoride Aluminium(II) oxide Argonium Carbon cation Carbon monophosphide Carbon monosulfide Carbon monoxide Cyano radical Diatomic carbon Fluoromethylidynium Helium hydride ion Hydrogen chloride Hydrogen fluoride Hydrogen (molecular) Hydroxyl radical Iron(II) oxide Magnesium monohydride Methylidyne radical Nitric oxide Nitrogen (molecular) Imidogen Sulfur mononitride Oxygen (molecular) Phosphorus monoxide Phosphorus mononitride Potassium chloride Silicon carbide Silicon monoxide Silicon monosulfide Sodium chloride Sodium iodide Sulfanyl Sulfur monoxide Titanium(II) oxide
Triatomic	Aluminium(I) hydroxide Aluminium isocyanide Amino radical Carbon dioxide Carbonyl sulfide CCP radical Chloronium Diazenylium Dicarbon monoxide Disilicon carbide Ethynyl radical Formyl radical Hydrogen cyanide (HCN) Hydrogen isocyanide (HNC) Hydrogen sulfide Hydroperoxyl Iron cyanide Isoformyl Magnesium cyanide Magnesium isocyanide Methylene N₂H Nitrous oxide Nitroxyl Ozone Methylidynephosphane Potassium cyanide Trihydrogen cation Sodium cyanide Sodium hydroxide Silicon carbonitride c-Silicon dicarbide SiNC Sulfur dioxide Thioformyl Thioxoethenylidene Titanium dioxide Tricarbon Water
Four atoms	Acetylene Ammonia Isocyanic acid Cyanoethynyl Formaldehyde Fulminic acid HCCN Hydrogen peroxide Hydromagnesium isocyanide Isocyanic acid Isothiocyanic acid Ketenyl Methylene amidogen Methyl cation Methyl radical Propynylidyne Protonated carbon dioxide Protonated hydrogen cyanide Silicon tricarbide Thioformaldehyde Tricarbon monoxide Tricarbon monosulfide Thiocyanic acid
Five atoms	Ammonium ion Butadiynyl Carbodiimide Cyanamide Cyanoacetylene Cyanoformaldehyde Cyanomethyl Cyclopropenylidene Formic acid Isocyanoacetylene Ketene Methane Methoxy radical Methylenimine Propadienylidene Protonated formaldehyde Silane Silicon-carbide cluster
Six atoms	Acetonitrile Cyanobutadiynyl radical E-Cyanomethanimine Cyclopropenone Diacetylene Ethylene Formamide HC₄N Ketenimine Methanethiol Methanol Methyl isocyanide Pentynylidyne Propynal Protonated cyanoacetylene
Seven atoms	Acetaldehyde Acrylonitrile Vinyl cyanide Cyanodiacetylene Ethylene oxide Glycolonitrile Hexatriynyl radical Propyne Methylamine Methyl isocyanate Vinyl alcohol
Eight atoms	Acetic acid Aminoacetonitrile Cyanoallene Ethanimine Glycolaldehyde Hexapentaenylidene Methylcyanoacetylene Methyl formate Acrolein
Nine atoms	Acetamide Cyanohexatriyne Dimethyl ether Ethanol Methyldiacetylene Octatetraynyl radical Propene Ethanethiol Propionitrile N-Methylformamide
Ten atoms or more	Acetone Benzene Benzonitrile Buckminsterfullerene (C₆₀, C₆₀, fullerene, buckyball) C₇₀ fullerene Cyanodecapentayne Ethylene glycol Ethyl formate Methyl acetate Methyl-cyano-diacetylene Methyltriacetylene Propionaldehyde Butyronitrile Pyrimidine Heptatrienyl radical

Deuterated
molecules

Unconfirmed

v t e Chlorine compounds
Chlorides and acids	HCl HClO HClO₂ HClO₃ HClO₄ HSO₃Cl BaClF BCl₃ CCl₄ SiCl₄ TiCl₄ C₃H₅Cl
Chlorine fluorides	ClF ClF₃ ClF₅
Chlorine oxides	ClO ClO₂ Cl₂O Cl₂O₂ Cl₂O₃ Cl₂O₄ Cl₂O₅ Cl₂O₆ Cl₂O₇ ClO₄
Chlorine oxyfluorides	ClOF ClOF₃ ClO₂F ClOF₅ (predicted) ClO₂F₃ ClO₃F
Chlorine(I) derivatives	ClNO₃ ClSO₃F ClN₃ Cl₃N

Salts and covalent derivatives of the chloride ion

HCl

LiCl

BeCl₂

B₄Cl₄
B₁₂Cl₁₂
BCl₃
B₂Cl₄
+BO₃

C₂Cl₂
C₂Cl₄
C₂Cl₆
CCl₄
+C
+CO₃

NCl₃
ClN₃
+N
+NO₃

Cl_xO_y
Cl₂O
Cl₂O₂
ClO
ClO₂
Cl₂O₄
Cl₂O₆
Cl₂O₇
ClO₄
+O

ClF
ClF₃
ClF₅

NaCl

MgCl₂

AlCl
AlCl₃

Si₅Cl₁₂
Si₂Cl₆
SiCl₄

P₂Cl₄
PCl₃
PCl₅
+P

S₂Cl₂
SCl₂
SCl₄
+SO₄

Cl₂

KCl

CaCl
CaCl₂

ScCl₃

TiCl₂
TiCl₃
TiCl₄

VCl₂
VCl₃
VCl₄
VCl₅

CrCl₂
CrCl₃
CrCl₄

MnCl₂
MnCl₃

FeCl₂
FeCl₃

CoCl₂
CoCl₃

NiCl₂

CuCl
CuCl₂

ZnCl₂

GaCl
GaCl₃

GeCl₂
GeCl₄

AsCl₃
AsCl₅
+As

Se₂Cl₂
SeCl₂
SeCl₄

BrCl

RbCl

SrCl₂

YCl₃

ZrCl₂
ZrCl₃
ZrCl₄

NbCl₃
NbCl₄
NbCl₅

MoCl₂
MoCl₃
MoCl₄
MoCl₅
MoCl₆

TcCl₃
TcCl₄

RuCl₂
RuCl₃
RuCl₄

RhCl₃

PdCl₂

AgCl

CdCl₂

InCl
InCl₂
InCl₃

SnCl₂
SnCl₄

SbCl₃
SbCl₅

Te₃Cl₂
TeCl₂
TeCl₄

ICl
ICl₃

XeCl
XeCl₂
XeCl₄

CsCl

BaCl₂

LuCl₃

HfCl₄

TaCl₃
TaCl₄
TaCl₅

WCl₂
WCl₃
WCl₄
WCl₅
WCl₆

ReCl₃
ReCl₄
ReCl₅
ReCl₆

OsCl₂
OsCl₃
OsCl₄
OsCl₅

IrCl₂
IrCl₃
IrCl₄

PtCl₂
PtCl₄

AuCl
(Au)₂
AuCl₃

Hg₂Cl₂
HgCl₂

TlCl
TlCl₃

PbCl₂
PbCl₄

BiCl₃

PoCl₂
PoCl₄

AtCl

FrCl

RaCl₂

LrCl₃

RfCl₄

DbCl₅

SgO₂Cl₂

BhO₃Cl

LaCl₃

CeCl₃

PrCl₃

NdCl₂
NdCl₃

PmCl₃

SmCl₂
SmCl₃

EuCl₂
EuCl₃

GdCl₃

TbCl₃

DyCl₂
DyCl₃

HoCl₃

ErCl₃

TmCl₂
TmCl₃

YbCl₂
YbCl₃

AcCl₃

ThCl₃
ThCl₄

PaCl₄
PaCl₅

UCl₃
UCl₄
UCl₅
UCl₆

NpCl₃

PuCl₃

AmCl₂
AmCl₃

CmCl₃

BkCl₃

CfCl₃
CfCl₂

EsCl₂
EsCl₃

FmCl₂

MdCl₂

NoCl₂

Binary compounds of hydrogen

Alkali metal
(Group 1) hydrides

Alkaline
(Group 2)
earth hydrides

Monohydrides	BeH MgH CaH SrH BaH

Dihydrides	BeH₂ MgH₂ CaH₂ SrH₂ BaH₂

Group 13
hydrides

Boranes	BH₃ BH B₂H₆ B₂H₂ B₂H₄ B₄H₁₀ B₅H₉ B₅H₁₁ B₆H₁₀ B₆H₁₂ B₁₀H₁₄ B₁₈H₂₂

Alanes	AlH₃ Al₂H₆

Gallanes	GaH₃ Ga₂H₆

Indiganes	InH₃ In₂H₆

Thallanes	TlH₃ Tl₂H₆

Nihonanes (predicted)	NhH NhH₃ Nh₂H₆ NhH₅

Group 14 hydrides

Hydrocarbons	alkanes alkenes alkynes Cycloalkanes Cycloalkenes Cycloalkynes Annulenes

Silanes	SiH₄ Si₂H₆ Si₃H₈ Si₄H₁₀ Si₅H₁₂ Si₆H₁₄ Si₇H₁₆ Si₈H₁₈ Si₉H₂₀ Si₁₀H₂₂ more...

Silenes	Si₂H₄

Silynes	Si₂H₂ SiH

Germanes	GeH₄ Ge₂H₆ Ge₃H₈ Ge₄H₁₀ Ge₅H₁₂

Stannanes	SnH₄ Sn₂H₆

Plumbanes	PbH₄

Flerovanes (predicted)	FlH FlH₂ FlH₄

Pnictogen
(Group 15) hydrides

Azanes	NH₃ N₂H₄ N₃H₅ N₄H₆ N₅H₇ N₆H₈ N₇H₉ N₈H₁₀ N₉H₁₁ N₁₀H₁₂ more...

Azenes	N₂H₂ N₃H₃ N₄H₄

Phosphanes	PH₃ P₂H₄ P₃H₅ P₄H₆ P₅H₇ P₆H₈ P₇H₉ P₈H₁₀ P₉H₁₁ P₁₀H₁₂ more...

Phosphenes	P₂H₂ P₃H₃ P₄H₄

Arsanes	AsH₃ As₂H₄

Stibanes	SbH₃

Bismuthanes	BiH₃

Moscovanes	McH₃ (predicted)

HN₃
NH
HN₅
NH₅ (hypothetical)

Hydrogen
chalcogenides
(Group 16 hydrides)

Polyoxidanes	H₂O H₂O₂ H₂O₃ H₂O₄ H₂O₅ more...

Polysulfanes	H₂S H₂S₂ H₂S₃ H₂S₄ H₂S₅ H₂S₆ H₂S₇ H₂S₈ H₂S₉ H₂S₁₀ more...

Selanes	H₂Se H₂Se₂

Tellanes	H₂Te H₂Te₂

Polanes	PoH₂

Livermoranes	LvH₂ (predicted)

HO
HO₂
HO₃
H₂O–O (hypothetical)
HS
HDO
D₂O
T₂O

Hydrogen halides
(Group 17 hydrides)

HCl

HBr

HAt

HTs (predicted)

Transition metal hydrides

Lanthanide hydrides

Actinide hydrides

Exotic matter hydrides

Categories: