# Nickel hydrazine nitrate

Nickel hydrazine nitrate (NHN), (chemical formula: [Ni(N$_2$H$_4$)$_3$](NO$_3$)$_2$ is an energetic material having explosive properties in between that of primary explosive and a secondary explosive. It is a salt of a coordination compound of nickel with a reaction equation of 3N$_2$H$_4$·H$_2$O + Ni(NO$_3$)$_2$ →〔Ni(N$_2$H$_4$)$_3$〕(NO$_3$)$_2$ ＋ 3H$_2$O

## Preparation

NHN can be synthesized by reacting nickel(II) nitrate hexahydrate with a dilute aqueous solution of hydrazine monohydrate at 65 C. To help speed the drying of the product after filtration from the hot water, it can be rinsed with alcohol. The product is a fluffy powder (density=0.9 g/cm$^3$). To increase its bulk density to (1.2 g/cm$^3$), dextrin in the amount of (1%) of the weight of the nickel(II) nitrate hexahydrate can be added.

## Non-primary explosive detonator (NPED)

The sensitivity of NHN straddles the line between highly sensitive primaries and a sensitive secondary, so it can be considered a true non-primary explosive detonator (NPED).
Another benefit of NHN is that it will make the DDT (deflagration to detonation transition) in a cardboard shell, eliminating the danger of shrapnel from a metal shell.

## Safety

NHN straddles the line between primary and secondary. Because of this it is a relatively safe explosive to work with having 80x less sensitivity to friction (16.0 N) than lead azide (0.1N) as shown in table 2.
Friction sensitivities of some traditional explosives (lead azide – 0.1N; lead styphnate – 1.5 N; mercury fulminate (white) – 5.0 N; tetrazene – 8.0 N; PETN – 60 N; RDX – 120 N; HMX – 120 N, show that NHN is not very sensitive, and is thereby not exceedingly hazardous in handling.

## General and structural properties of Nickel hydrazine nitrate

Source:
| Molecular formula | Ni H$_{12}$ N$_8$ O$_6$ |
| Formula weight | 278.69 |
| Color | Purple Violet |
| Crystal density (g/cm$^3$) | 2.1 |
| Average particle size (μm) | 13 |
| Nickel content (%) | 21.16 (21.06) $^a$ |
| Hydrazine content (%) | 34.46 (34.45) $^a$ |
| Nitrate content (%) | 44.47 (44.49) $^a$ |
| Nitrogen content in coordination sphere (%) | 30.25 (30.14) $^a$ |
| FTIR peaks, (cm$^{−1}$) | 3238, 1630 (NH$_2$); 1356,1321 (-NO$_3$) |
| Moisture content (at 333 K for 10 min) (%) | 0.34 |
| Average mol wt of combustion products | 27.35 |
| Percent condensable Ni (l) | 18 |
| Oxygen-fuel ratio | 0.8571 |
| Oxygen balance % | -5.74 |
$^a$ Values in brackets are theoretical

## Comparative properties of Nickel hydrazine nitrate, lead azide and lead styphnate

| Property | Nickel hydrazine nitrate $^a$ | Lead azide $^b$ | Lead styphnate |
| Crystal Density (g/cm$^3$) | 2.129 | 4.38 | 3.02 |
| Oxygen balance (%) | – 5.74 $^c$ | – 5.50 | -19.00 |
| Heat of combustion (kJ/kg) | 5225 | 2635 | 5234 |
| Heat of formation (kJ/mol) | – 449 | 469 | -385 |
| Heat of explosion (kJ/kg) | 4390 | 1610 | 1912 |
| Pressure output in closed vessel (100 mg in 48 cm$^3$) (kg/cm$^2$) | 17.5 | 8.2 $^c$ | |
| Onset of decomposition (K) | 505.7 | 463 | 533.15 |
| Peak of decomposition (K) | 506.5 | 618 | 583.15 |
| Friction sensitivity (kg f) | 1.6 | 0.02 | .15 |
| Impact sensitivity (cm, 400 g wt, 20 mg sample, 50% explosion) | 21 $^b$ | 10.5 | 11 |
| ESD sensitivity (J) | 0.02 $^b$ | 0.004 | .0002 |
| Vol. of detonation gases (ml/g) | 884 $^c$ | 308 | 368 |
| Detonation temperature (K) | 2342 $^c$ | 5600 | |
| Detonation pressure (GPa) | 20.8 $^c$ (1.7 g/cm$^3$) | 16.1 (3.0 g/cm$^3$) | |
| Detonation velocity (m/s) | 7000 $^b$ (1.7 g/cm$^3$) | 4630 (3.0 g/cm$^3$) | 5200 (2.9 g/cm$^3$) |
| RE Factor | 1.05 $^b$ (1.7 g/cm$^3$) | .8 (3.0 g/cm$^3$) | |
$^a$ Experimental value, $^b$ literature value, and $^c$ theoretical value