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Germane is the
chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) composed of atoms from more than one chemical element, element held together by chemical bonds. A homonuclear molecule, m ...
with the formula
Ge
Ge
H4
H<sub>4</sub>
, and the
germanium Germanium is a chemical element with the Symbol (chemistry), symbol Ge and atomic number 32. It is a lustrous, hard-brittle, grayish-white metalloid in the carbon group, chemically similar to its group neighbors silicon and tin. Pure germanium i ...

germanium
analogue of
methane Methane (, ) is a chemical compound with the chemical formula A chemical formula is a way of presenting information about the chemical proportions of s that constitute a particular or molecule, using symbols, numbers, and sometimes a ...
. It is the simplest germanium hydride and one of the most useful compounds of germanium. Like the related compounds
silane Silane is a molecule of one central silicon atom with four attachments. The attachments can be any combination of organic or inorganic groups. An example is silane tetrahydride an inorganic compound In chemistry Chemistry is the science, s ...

silane
and methane, germane is
tetrahedral In geometry Geometry (from the grc, γεωμετρία; ' "earth", ' "measurement") is, with , one of the oldest branches of . It is concerned with properties of space that are related with distance, shape, size, and relative position ...
. It burns in air to produce GeO2 and
water Water (chemical formula H2O) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known li ...
. Germane is a
group 14 hydride Group 14 hydrides are chemical compounds composed of hydrogen atoms and group 14 atoms (the elements of group 14 are carbon, silicon Silicon is a chemical element with the Symbol (chemistry), symbol Si and atomic number 14. It is a hard, brit ...
.


Occurrence

Germane has been detected in the atmosphere of
Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...

Jupiter
.


Synthesis

Germane is typically prepared by reduction of germanium compounds, notably
germanium dioxide Germanium dioxide, also called germanium oxide, germania, and salt of germanium, is an inorganic compound In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed ...
, with hydride reagents such as
sodium borohydride Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to ...

sodium borohydride
,
potassium borohydride of the borohydride anion, Borohydride refers to the anion and its salts. Borohydride is also the term used for compounds containing , for example cyanoborohydride () and Lithium triethylborohydride, triethylborohydride (B(C2H5)3H−). Borohydrid ...

potassium borohydride
,
lithium borohydride Lithium borohydride (LiBH4) is a borohydride and known in organic synthesis as a reducing agent for esters. Although less common than the related sodium borohydride, the lithium salt offers some advantages, being a stronger reducing agent and high ...
,
lithium aluminium hydride Lithium aluminium hydride, commonly abbreviated to LAH, is an inorganic compound In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their ...

lithium aluminium hydride
,
sodium aluminium hydride Sodium aluminium hydride or sodium alanate is an inorganic compound In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their co ...
. The reaction with borohydrides is catalyzed by various acids and can be carried out in either aqueous or organic
solvent A solvent (from the Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the ...

solvent
. On laboratory scale, germane can be prepared by the reaction of Ge(IV) compounds with these
hydride In chemistry, a hydride is formally the anion of hydrogen, H−. The term is applied loosely. At one extreme, all chemical compound, compounds containing covalent bond, covalently bound H atoms are called hydrides: water (H2O) is a hydride of o ...

hydride
reagents. A typical synthesis involved the reaction of Na2GeO3 with
sodium borohydride Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to ...

sodium borohydride
. :Na2GeO3 + NaBH4 + H2O → GeH4 + 2 NaOH + NaBO2 Other methods for the synthesis of germane include
electrochemical reduction Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential, as a measurable and quantitative phenomenon, and identifiable chemical change, with either electrical potential as an outcome of a pa ...
and a
plasma Plasma or plasm may refer to: Science * Plasma (physics), one of the four fundamental states of matter * Plasma (mineral) or heliotrope, a mineral aggregate * Quark–gluon plasma, a state of matter in quantum chromodynamics Biology * Blood plasma ...
-based method. The electrochemical reduction method involves applying
voltage Voltage, electric potential difference, electric pressure or electric tension is the difference in electric potential The electric potential (also called the ''electric field potential'', potential drop, the electrostatic potential) is the ...

voltage
to a germanium metal
cathode A cathode is the from which a leaves a polarized electrical device. This definition can be recalled by using the ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in which positive charges move. Electrons ha ...
immersed in an aqueous
electrolyte An electrolyte is a medium containing ions that is electrically conducting Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that quantifies how strongly it resis ...

electrolyte
solution and an
anode An anode is an electrode An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor A semiconductor material has an Electrical resistivity and conductivity, electrical conductiv ...

anode
counter-electrode composed of a metal such as
molybdenum Molybdenum is a chemical element In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behav ...

molybdenum
or
cadmium Cadmium is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical eleme ...

cadmium
. In this method, germane and
hydrogen Hydrogen is the chemical element with the Symbol (chemistry), symbol H and atomic number 1. Hydrogen is the lightest element. At standard temperature and pressure, standard conditions hydrogen is a gas of diatomic molecules having the che ...

hydrogen
gases evolve from the cathode while the anode reacts to form solid molybdenum oxide or
cadmium oxide Cadmium oxide is an inorganic compound In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, propert ...

cadmium oxide
s. The plasma synthesis method involves bombarding germanium metal with hydrogen atoms (H) that are generated using a high
frequency Frequency is the number of occurrences of a repeating event per unit of time A unit of time is any particular time Time is the indefinite continued sequence, progress of existence and event (philosophy), events that occur in an apparen ...

frequency
plasma source to produce germane and
digermane
digermane
.


Reactions

Germane is weakly
acid An acid is a or capable of donating a (hydrogen ion H+) (a ), or, alternatively, capable of forming a with an (a ). The first category of acids are the proton donors, or s. In the special case of , proton donors form the H3O+ and are ...
ic. In liquid ammonia GeH4 is ionised forming NH4+ and GeH3. With alkali metals in liquid ammonia GeH4 reacts to give white crystalline MGeH3 compounds. The potassium (potassium germyl KGeH3) and rubidium compounds (rubidium germyl RbGeH3) have the
sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salt (chemistry), salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With Molar mass, molar ...
structure implying a free rotation of the GeH3 anion, the caesium compound, CsGeH3 in contrast has the distorted sodium chloride structure of TlI.


Use in semiconductor industry

The gas decomposes near 600K (327°C; 620°F) to germanium and hydrogen. Because of its thermal
lability Lability refers to something that is constantly undergoing change or is likely to undergo change. Biochemistry In reference to biochemistry Biochemistry or biological chemistry, is the study of es within and relating to living s. A sub-d ...

lability
, germane is used in the
semiconductor A semiconductor material has an electrical conductivity Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric curre ...
industry for the
epitaxial Epitaxy refers to a type of crystal growth or material deposition in which new crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopi ...
growth of germanium by
MOVPE Metalorganic vapour-phase epitaxy (MOVPE), also known as organometallic Organometallic chemistry is the study of organometallic compounds, chemical compound A chemical compound is a chemical substance A chemical substance is a form of m ...
or chemical beam epitaxy. Organogermanium precursors (e.g.
isobutylgermane Isobutylgermane (IBGe, Chemical formula A chemical formula is a way of presenting information about the chemical proportions of atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matt ...
, alkylgermanium trichlorides, and dimethylaminogermanium trichloride) have been examined as less hazardous liquid alternatives to germane for deposition of Ge-containing films by MOVPE.


Safety

Germane is a highly
flammable A combustible material is something that can burn (i.e., ''combust'') in air. A combustible material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort and a flammable mat ...
, potentially
pyrophoric A substance is pyrophoric (from grc-gre, πυροφόρος, , 'fire-bearing') if it ignites spontaneously in air at or below (for gases) or within 5 minutes after coming into contact with air (for liquids and solids). Examples are iron sulfid ...
, and a highly toxic gas. In 1970, the
American Conference of Governmental Industrial Hygienists The American Conference of Governmental Industrial Hygienists (ACGIH) is a professional association of industrial hygienists and practitioners of related professions, with headquarters in Cincinnati, Ohio. One of its goals is to advance worker pro ...
(ACGIH) published the latest changes and set the occupational exposure threshold limit value at 0.2 ppm for an 8-hour time weighted average.Praxair MSDS
accessed Sep. 2011
The
LC50 In toxicology Toxicology is a scientific discipline Discipline is action ACTION is a bus operator in Canberra Canberra ( ) is the capital city of Australia. Founded following the Federation of Australia, federation of the col ...
for rats at 1 hour of exposure is 622 ppm. Inhalation or exposure may result in malaise, headache, dizziness, fainting, dyspnea, nausea, vomiting, kidney injury, and hemolytic effects. The
US Department of Transportation The United States Department of Transportation (USDOT or DOT) is a federal Cabinet Cabinet or The Cabinet may refer to: Furniture * Cabinetry, a box-shaped piece of furniture with doors and/or drawers * Display cabinet, a piece of furnitur ...
hazard class Dangerous goods, abbreviated DG, are substances that when transported are a risk to health, safety, property or the environment Environment most often refers to: __NOTOC__ * Natural environment, all living and non-living things occurring natura ...
is 2.3 Poisonous Gas.


References


External links


Metaloids (manufacturer) datasheetArkonic Specialty Gases China (manufacturer) datasheetPraxair datasheetAir liquide gas encyclopedia entryVoltaix (manufacturer) datasheetFoshan Huate Gas Co.,Ltd. (manufacturer)Horst Technologies, Russia (manufacturer)
{{Hydrides by group Germanium compounds Metal hydrides Industrial gases