Solid phase
Official name
Diammonium hydrogen phosphate (phase beta)
Secondary names
diazanium;hydrogen phosphate; Ammonium phosphate, dibasic; Dibasic ammonium phosphate; Phosphoric acid, diammonium salt; Diammonium orthophosphate; (NH4)2HPO4; (NH4)2HPO42-beta; H9N2O4P
CAS number
7783-28-0
Type
Family
ionic solid
Class
acid salt
Compound type
phosphate
Chemical composition
Formula
(NH+4)2⋅HPO2−4
Chemical formula
(NH4)2HPO4
Elemental formula
(N+)2 H9 P O2 (O-)2
Isotope mixture type
terrestrial abundance
6.0
  Formula Name Family Number min-max Mole fraction Isotope mole fraction State Relevance
NH+4 Ammonium ion molecule 2 0.6666666666666666 1 constituent cation main
HPO2−4 Hydrogen phosphate ion molecule 1 0.3333333333333333 1 constituent anion main
Chemical functions
  Function Number
H4>∣N+ 2
Chemical bonds
  Bond Number
>∣N+⋅O−− 1
−O…H− 2
≥N+−H 4
P=O 1
=P−O− 2
=P−O− 1
−O−H 1
Class
acid salts (05)
Type
simple acid salts (05.01)
Group
phosphate (05.01.07)
Phase name
Diammonium hydrogen phosphate-beta
Phase type
crystalline
Comments
fully ordered phase
Molar mass
115.109 g/mol
State NTP
solid
Phase transitions
Phase transition type Other phases Temperature - Pressure
solid-solid (NH4)2HPO4-gamma above -99°C (174 K)
Phase transitions comments
order-disorder phase transition at 174K
Pure color
colorless
Color
colorless, white
Diaphaneity
transparent to translucent
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