Ammonium dihydrophosphate

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Crystal compoundsSaltsSulfatesAmmonium dihydrophosphate


  Ammonium dihydrophosphate   
Names: ammonium dihydrogen phosphate
monoammonium phosphate
ADP

Formula: NH4H2PO4
SMILES: [NH4+].OP(=O)(O)[O-]
Molar mass: 115.025 g/mol
Density: 1.8 g/cm3
Crystal system: tetragonal
a=7.4997 Å
7.4997 Å
0.7500 nm
, b=7.4997 Å
7.4997 Å
0.7500 nm
, c=7.5493 Å
7.5493 Å
0.7549 nm
α=90°
90°  
, β=90°
90°  
, γ=90°
90°  

Shapes:
https://media.crystalls.info/w/uploads/media/Prolongated_tetragonal_pyramidal_prism.json
https://media.crystalls.info/w/uploads/media/Beveled_tetragonal_prism.json
https://media.crystalls.info/w/uploads/media/Needle.json

Color: colorless
Melting point: 190 °C
463.15 K
374 °F
833.67 °R

Decomposition point: 250 °C
523.15 K
482 °F
941.67 °R

Refractive index: 1.525
Optical properties: birefringence
Electricity properties: piezoelectric
ferroelectric
dielectric
Stability: stable
Hardness: relatively strong
(2 on Moh`s scale)
Toxicity: non-toxic
LD50=5750mg/kg

Description

Inorganic compound, acid salt of ammonium ion and inorganic phosphoric acid. Doesn`t form water hydrates.

Minerals

Occurs in nature as biphosphammite and archerite minerals.

Where to buy

In fertilizers store (as "ammophos").

Precursors

Reaction between ammonia and phosphoric acid

Chemical equation:

NH4OH + H3PO4 = NH4H2PO4 + H2O

For preparation of 100.00g of ammonium dihydrophosphate а 121.87g of 25% ammonia and 100.23g of 85% phosphoric acid is required.
Add hot acid to the flask, then add small parts of ammonium compound with stirring until heating will stop (attention, the solution may boil!) . After reaction will stop, filter the solution and use it for crystal growing.

Influence of impurities

Small addition of baking soda or ammonia improves crystal form and transparency.

Influence of pH level

Sharp or needle crystals are forming at lower pH.

Storage conditions

Store in its original form or under several layers of varnish at average humidity and room temperature. Do not store in matchboxes or cotton wool and do not heat.

Solubility

Temperatureгр/100,00 гр water
0°C
273.15 K
32 °F
491.67 °R
22.6
22.6 g/100g
18.434 %
10°C
283.15 K
50 °F
509.67 °R
28
28 g/100g
21.875 %
15°C
288.15 K
59 °F
518.67 °R
~31.7
31.7 g/100g
24.07 %
20°C
293.15 K
68 °F
527.67 °R
35.3
35.3 g/100g
26.09 %
25°C
298.15 K
77 °F
536.67 °R
39.5
39.5 g/100g
28.315 %
30°C
303.15 K
86 °F
545.67 °R
43.9
43.9 g/100g
30.507 %
40°C
313.15 K
104 °F
563.67 °R
56.7
56.7 g/100g
36.184 %
50°C
323.15 K
122 °F
581.67 °R
~69.6
69.6 g/100g
41.038 %
60°C
333.15 K
140 °F
599.67 °R
82.5
82.5 g/100g
45.205 %
70°C
343.15 K
158 °F
617.67 °R
~100
100 g/100g
50 %
80°C
353.15 K
176 °F
635.67 °R
118.3
118.3 g/100g
54.191 %
90°C
363.15 K
194 °F
653.67 °R
~146
146 g/100g
59.35 %
100°C
373.15 K
212 °F
671.67 °R
173.2
173.2 g/100g
63.397 %
Soluble in ethanol. Insoluble in acetone.

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