Gah

Gah may refer to:

List of craters on Mars: A-G

This is a list of craters on Mars. There are hundreds of thousands of impact craters on Mars, but only some of them have names. This list here only contains named Martian craters starting with the letter A – G (see also lists for H – N and O – Z).

Large Martian craters (greater than 60 km in diameter) are named after famous scientists and science fiction authors; smaller ones (less than 60 km in diameter) get their names from towns on Earth. Craters cannot be named for living people, and small crater names are not intended to be commemorative - that is, a small crater isn't actually named after a specific town on Earth, but rather its name comes at random from a pool of terrestrial place names, with some exceptions made for craters near landing sites. Latitude and longitude are given as planetographic coordinates with west longitude.

A

B

C

D

E

F

G

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Gallane

Gallane is an inorganic compound with the chemical formula GaH₃ . It has been detected as a transient species in the gas phase; also at low temperature (3.5 K) following the reaction of laser ablated gallium atoms and dihydrogen, and more recently in an argon matrix doped with vapour over solid digallane, Ga₂H₆.

Nomenclature

The systematic names, gallane and trihydridogallium, valid IUPAC names, are constructed according to the substitutive and additive nomenclatures, respectively.

Gallane is also used, systematically, to refer to the parent class containing gallane proper, and hence to categorise the members of the parent class. Care should be taken to avoid confusing the compound for the class.

Structure of monomeric GaH₃

I.R spectroscopic studies indicate that monomeric GaH₃ has a trigonal planar structure Theoretical Ga-H bond lengths have been calculated as being in the range 155.7 pm to 158.7 pm

Monomeric GaH₃ dimerises in the vapor phase to form Ga₂H₆, digallane(6) and the enthalpy change associated with the gas phase dissociation reaction Ga₂H₆ → 2GaH₃ has been experimentally estimated as 59 +/- 16 kJ mol⁻¹.