Ammonium chloride (beta-, phase II) | SSHADE

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Solid phase

Official name: Ammonium chloride (beta-, phase II)

Name and identifiers

Secondary names: Sal ammoniac; Salmiac; Salmiak; NH4Cl; NH4Cl-II; beta-NH4Cl; NH4+Cl-; ClH4N
CAS number: 12125-02-9

Family: ionic solid
Class: normal salt
Compound type: chloride

Chemical composition

Formula: $NH_4^+ \cdot Cl^-$
Chemical formula: NH4Cl
Elemental formula: (N+) H4 (Cl-)
Isotope mixture type: terrestrial abundance

4.0

	Formula	Name	Family	Number min-max	Mole fraction	Isotope mole fraction	State	Relevance
	$NH_4^+$	Ammonium ion	molecule	1	0.5	1	constituent cation	main
	$Cl^-$	Chloride anion	element	1	0.5	1	constituent anion	main

Chemical functions and bonds

Chemical functions

	Function	Number
	$H_4 >\mid N^+$	1

Chemical bonds

	Bond	Number
	$>\mid N^+ \cdot Cl^{-}$	1
	$\geq N^+-H$	4

Class: normal salts (07)
Type: simple normal salts (07.01)
Group: chloride (07.01.03)

Crystallography

Phase name: beta-NH4Cl (phase II)
Phase type: crystalline
Crystal system: isometric (cubic)
Crystal class: hexoctahedral
Crystal class symbol: m-3m (Oh)
Crystal spacegroup: Pm-3m
Comments: disordered orientation of $NH_4^+$ : two possible $NH_4^+$ orientations (Fig. 1a) A and B which are randomly distributed

Physical properties

Molar mass: 53.49 $g/mol$
Density: 1.519 $g/cm^3$

Thermodynamical properties

State NTP

solid

Phase transitions

Phase transition type	Other phases	Temperature - Pressure
solid-gas	gas decomposition	337.6 °C (610.8 k) at 1 atm
solid-solid	delta-NH4Cl (phase IV)	below -30.4°C (242.8K)

Optical properties

Refringence type: isotropic
Refraction index $n_{\alpha}$: 1.642
Pure color: colorless
Color: colorless, white
Diaphaneity: transparent to translucent

Links and Publications

Links

Wikipedia: Ammonium chloride