Inorganic imide
The inorganic imides are compounds containing an ion composed of
In addition to solid state imides, molecular imides are also known in dilute gases, where their spectrum can be studied.
When covalently bound to a metal, an imide ligand produces a transition metal imido complex.
When the hydrogen of the imide group is substituted by an organic group, an
Properties
Lithium imide undergoes a phase transition at 87 °C where it goes from an ordered to a more symmetric disordered state.[2]
Structure
Many imides have a cubic rock salt structure, with the metal and nitrogen occupying the main positions. The position of the hydrogen atom is hard to determine, but is disordered.
Many of the heavy metal simple imide molecules are linear. This is due to the filled 2p orbital of nitrogen donating electrons to an empty d orbital on the metal.[3]
Formation
Heating lithium amide with lithium hydride yields lithium imide and hydrogen gas. This reaction takes place as released ammonia reacts with lithium hydride.[2]
Heating magnesium amide to about 400 °C yields magnesium imide with the loss of ammonia. Magnesium imide itself decomposes if heated between 455 and 490 °C.[4]
Beryllium imide forms from beryllium amide when heated to 230 °C in a vacuum.[5]
When strontium metal is heated with ammonia at 750 °C, the dark yellow strontium imide forms.[6]
When barium vapour is heated with ammonia in an electrical discharge, the gaseous, molecular BaNH is formed.[7] Molecules ScNH, YNH, and LaNH are also known.[8][9]
Hydrogen storage
Inorganic imides are of interest because they can reversibly store hydrogen, which may be important for the
List
Ionic
name | formula | structure | space group | unit cell | references |
---|---|---|---|---|---|
Lithium imide | Li2NH | cubic | Fm3m | a=5.0742 | [2] |
Beryllium imide | BeNH | [5] | |||
Magnesium imide | MgNH | hexagonal | P6/m | a = 11.567 Å c = 3.683Å Z=12 | [4] |
Lithium magnesium imide | Li2Mg(NH)2 | [10] | |||
Si2N2(NH) | [11] | ||||
K2Si(NH)3 | amourphous | [12] | |||
K2Si2(NH)5 | amourphous | [12] | |||
K2Si3(NH)7 | amourphous | [12] | |||
potassium imido nitrido silicate | K3Si6N5(NH)6 | cubic | P4332 | a = 10.789 | [11] |
Calcium imide | CaNH | hexagonal | Fm3m | [10] | |
Lithium calcium imide | Li2Ca(NH)2 | hexagonal | [10] | ||
Magnesium calcium diimide | MgCa(NH)2 | cubic | [13] | ||
Lithium calcium magnesium imide | Li4CaMg(NH)4 | [10] | |||
Strontium imide | SrNH | orthorhombic | Pmna | a =7.5770 b =3.92260 c =5.69652 Z=4 | [6] |
Tin amide imide | Sn(NH2)2NH | [14][15] | |||
Barium imide | BaNH | tetragonal | I4/mmm | a=4.062 c=6.072 Z=2 | [16] |
Lanthanum imide | La2(NH)3 | rock salt | a=5.32 | [17] | |
Cerium imide | CeNH | [18] | |||
Ytterbium imide | YbNH | cubic | a=4.85 | [19] | |
NH4[Hg3(NH)2](NO3)3 | cubic | P4132 | a = 10.304, Z = 4 | [20] | |
Thorium nitride imide | Th2N2(NH) | hexagonal | P3m1 | a = 3.886 c = 6.185 Å | [21] |
Molecular
name | formula | structure | symmetry | CAS | references |
---|---|---|---|---|---|
B2(NH)3 | polymer | [22] | |||
Nitroxyl | HNO | bent | 14332-28-6 | ||
Al(NH2)(NH) | polymer | [22] | |||
silicon dimide | Si(NH)2 | ||||
thionitrosyl hydride | HNS | bent | 14616-59-2 | [23] | |
sulfur diimide | S(NH)2 | ||||
Heptasulfur imide | S7NH | 293-42-5 | [24] | ||
1,2,3,4,5,7,6,8-Hexathiadiazocane
1,3-Hexasulfurdiimide |
H2N2S6 | 1003-75-4 | |||
1,2,3,4,6,7,5,8-Hexathiadiazocane
1,4-Hexasulfurdiimide |
H2N2S6 | 1003-76-5 | |||
1,2,3,5,6,7,4,8-Hexathiadiazocane
1,5-Hexasulfurdiimide |
H2N2S6 | ||||
1,2,3,5,7,4,6,8-Pentathiatriazocane | H3N3S5 | 638-50-6 | |||
ScNH | [8] | ||||
Ga2(NH)3 | polymer | [22] | |||
YNH | [8] | ||||
BaNH | linear | [3] | |||
LaNH | linear | C∞v | [9][25] | ||
CeNH | linear | C∞v | [25] | ||
Uranimine nitride | N≡U═N−H | [26] | |||
Uranimine dihydride | HN═UH2 | [26] |
Molecular imines of other actinides called neptunimine and plutonimine have been postulated to exist in the gas phase or noble gas matrix.[27]
References
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