Mineral phase
IMA name
Biphosphammite
Secondary names
Ammonium dihydrogen phosphate
CAS number
7722-76-1
Type
Class
non-silicate mineral
Compound type
phosphate
Chemical composition
Formula
$(NH_4,K)H_2PO_4$
Chemical formula
(NH4,K)H2PO4
Elemental formula
(K+)0-1 (N+)0-1 (H)2-6 P O3 (O-)
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$K^+$ Potassium(1+) cation element 0 - 1 constituent cation main
$NH_4^+$ Ammonium ion molecule 0 - 1 constituent cation main
$H_2PO_4^-$ Dihydrogen phosphate ion molecule 1 constituent anion main
Chemical functions
  Function Number
$H_4 >\mid N^+$ 1
Chemical bonds
  Bond Number
$>\mid N^+ \cdot O^{-}-$ 1
$K^+ \cdot O^{-}-$
$\geq N^+-H$ 4
$=P-O^-$ 2
$=P-O-$ 2
$P=O$ 1
$-O-H$ 2
Oxides
Formula $K_{2}O$ $P_{2}O_{5}$ $H_{2}O$ $N_{2}O_{5}$
Mass fraction (%) 9.79 59.0 14.98
Oxides comments
calculated with N2O5 as (NH4)2O = 16.23%

Strunz

Class
phosphates - arsenates - vanadates (08)
Division
phosphates, etc. without additional anions, without H2O (08.A)
Family
with only large cations (08.AD)
Code
08.AD.15

Dana

Major class
phosphates, arsenates, vanadates (VII)
Class
anhydrous acid phosphates, etc (37)
Type
with miscellaneous formulae (37.01)
Group
-Biphosphammite- group (37.01.04)
Code
37.01.04.01
Phase type
crystalline
Crystal system
tetragonal
Crystal class
scalenohedral
Crystal class symbol
-42m (D2d)
Crystal spacegroup
I-42d
Molar mass
120.29 $g/mol$
Density
2.04 $g/cm^3$
State NTP
solid
Refringence type
uniaxial
Refringence sign
negative
Birefringence
0.045
Refraction index $n_o$ (w)
1.525
Refraction index $n_e$ (e)
1.48
Color
colorless, gray white, pale yellow, brown
Diaphaneity
transparent to translucent
Luster
vitreous
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