Arsenide hydride
# Arsenide hydride

An arsenide hydride or hydride arsenide is a chemical compound containing hydride $(H^−)$ and arsenide $(As^{3−})$ ions in a single phase. They are in the class of mixed anion compounds.

## Preparation

Arsenide hydride compounds may be produced by heating metal hydride and metal arsenide mixtures under pressure.

## Properties

Arsenide hydrides are under investigation as unconventional superconductors.

The hydride ions can be replaced by fluoride or oxide ions to yield variations in composition.

## Reactions

when heated to 800° CaFeAsH forms three phases.

2CaFeAsH → Ca + $CaFe_2As_2$ + $H_2$

| name | formula | form | space group | unit cell | volume | density | appearance | properties |
| - | - | - | - | - | - | - | - | - |
| | $LiCa_3As_2H$ | orthorhombic | Pnma | a = 11.4064(7) Å, b = 4.2702(3) Å, c = 11.8762 Z=4 | | | red | band gap 1.4 eV |
| | $Ca_{14}As_6C_{0.5},NH_5$ | tetragonal | P4/mbm | a = 15.749, c = 9.1062, Z = 4 | | | red | band gap 1.6 eV |
| | CaFeAsH | tetragonal | P4/nmm | a = 0.3878 c = 0.8260 | | | | superconductor |
| | $CaFeAsF_{1-x}H_x$ | | | | | | | non superconductor |
| | $CaFe_{1−x}Co_xAsH$ | tetragonal | P4/nmm | a increases and c decreases with x | | | | superconducting 23 K at x= 0.09 |
| | $K_2Cr_3As_3H$ | | | | | | | |
| | $K_{1−δ}Cr_3As_3H_x$ x<0.45 | | | | | | | Superconductor Tc=5.8 K |
| Lithium tristrontium diarsenide hydride | $Sr_3LiAs_2H$ | orthorhombic | Pnma | a = 12.034, b = 4.4698, c = 12.5907; V = 677.2 $Å^3$ | | | | Zintl phase; semiconductor; diamagnetic |
| | $LaFeAsO_{1−x}H_x$ (x<0.53) | | | | | | | superconductor $T_c=36$ K with x=0.3 |
| | $La_2Ti_2As_2H_{2.3}$ | tetragonal | I4/mmm | a=3.9595 c=18.0986 | 283.742 | | | |
| | $La_2V_2As_2H_x$ | tetragonal | I4/mmm | a=3.9561 c=17.909 | 280.030 | | | |
| | $La_2Cr_2As_2H_x$ | tetragonal | I4/mmm | a=3.9934 c=17.380 | 277.17 | | | |
| | $La_2Mn_2As_2H_x$ | tetragonal | I4/mmm | a=4.0556 c=17.46 | 287.2 | | | |
| | LaMnAsO1−xHx (x=0−0.73) | | | | | | | ferromagnetic |
| | $CoLaAsH_{0.78x}$ | orthorhombic | $I4_1md$ | a=4.1739 c=14.64 | 254.8 | | | black |
| | $NiLaAsH_{0.69}$ | orthorhombic | $I4_1md$ | a=4.1660 c=14.5993 | 253.37 | | | black |
| | $CuLaAsH_{0.78}$ | orthorhombic | $I4_1md$ | a=4.2302 c=14.5780 | 260.86 | 7.08 | | black |
| | $LaZn_{0.5}AsH_x$ | hexagonal | P6/mmm | a=4.200 c=4.244 | 64.81 | | | black |
| | $CeFeAsO_{1−x}H_x$ (x<0.5) | tetragonal | P4/nmm | a=3.95386 c=8.5926 at x=0.4 | | | | superconducting 0.1 < x < 0.4; $T_c=47$ K with x=0.25 |
| | NdFeAs(O,H) | | | | | | | superconductor Tc=40K |
| | $SmFeAsO_{1−x}H_x$ (x<0.5) | | | | | | | superconductor Tc=55 K at x = 0.2. |
| | $Sm_2Mn_2As_2H_x$ | tetragonal | I4/mmm | a=3.9251 c=16.67 | 256.7 | | | |
| | $GdFeAsO_{1−x}H_x$ | | | | | | | |
