Ammonium bromide

Ammonium bromide
Ammonium bromide
Are common
Systematic ; name	Ammonium bromide
Traditional names	Ammonium bromide
Chem. formula	NH 4 Br
Physical properties
condition	colorless crystals
Molar mass	97.943 g / mol
Density	2,429 g / cm³
Thermal properties
T. decomp.	394 ° C
Chemical properties
Solubility in water	59.5 0 ; 74.2 20 ; 119.3 80 ; 134.7 100 g / 100 ml
Optical properties
Refractive index	1,712
Classification
Reg. CAS number	12124-97-9
PubChem
Reg. EINECS number
Smiles
Inchi
RTECS	BO9155000
Chebi
ChemSpider

Ammonium bromide is an inorganic compound, a salt of ammonium and hydrobromic acid with the formula NH ₄ Br, colorless crystals soluble in water. When heated, sublimates and decomposes. It is steady in the light and in air (in the complete absence of impurities). It is well soluble in water (cation hydrolysis). Does not form crystalline hydrates.

Content

Getting

Dissolution of ammonia in hydrobromic acid :

{\mathsf {NH_{3}+HBr\ {\xrightarrow {}}\ NH_{4}Br}}

{\ displaystyle {\ mathsf {NH_ {3} + HBr \ {\ xrightarrow {}} \ NH_ {4} Br}}}

Reduction of bromine in a concentrated solution of ammonia :

{\mathsf {8NH_{3}+3Br_{2}\ {\xrightarrow {}}\ N_{2}\uparrow +6NH_{4}Br}}

{\ displaystyle {\ mathsf {8NH_ {3} + 3Br_ {2} \ {\ xrightarrow {}} \ N_ {2} \ uparrow + 6NH_ {4} Br}}}

Decomposition of ammonium carbonate with hydrobromic acid:

{\mathsf {(NH_{4})_{2}CO_{3}+2HBr\ {\xrightarrow {}}\ 2NH_{4}Br+CO_{2}\uparrow +H_{2}O}}

{\ displaystyle {\ mathsf {(NH_ {4}) _ {2} CO_ {3} + 2HBr \ {\ xrightarrow {}} \ 2NH_ {4} Br + CO_ {2} \ uparrow + H_ {2} O} }}

Physical Properties

Ammonium bromide forms colorless crystals (β-modification) of cubic syngony , space group P m3m , cell parameters a = 0.406 nm, Z = 1.

When heated, there is a phase transition to the α-modification of cubic syngony , space group F m3m , cell parameters a = 0.691 nm, Z = 4 (250 ° C).

At low temperatures, there is a γ modification — tetragonal syngony , space group P 4 b2 , cell parameters a = 0.4248 nm, c = 0.4035 nm, Z = 1.

It is well soluble in water, ethanol , acetone , ether .

Aqueous solutions have a slightly acid reaction due to hydrolysis .

Chemical Properties

When heated above 394 ° C, sublimes with decomposition:

{\mathsf {NH_{4}Br\ \rightleftarrows \ NH_{3}+HBr}}

{\ displaystyle {\ mathsf {NH_ {4} Br \ \ rightleftarrows \ NH_ {3} + HBr}}}

Decomposed by diluted acids:

{\mathsf {2NH_{4}Br+H_{2}SO_{4}\ {\xrightarrow {}}\ (NH_{4})_{2}SO_{4}+2HBr\uparrow }}

{\ displaystyle {\ mathsf {2NH_ {4} Br + H_ {2} SO_ {4} \ {\ xrightarrow {}} \ (NH_ {4}) _ {2} SO_ {4} + 2HBr \ uparrow}}}

It is oxidized by concentrated sulfuric acid (ω> 50%, horizontal):

{\mathsf {2NH_{4}Br+3H_{2}SO_{4}\ {\xrightarrow {}}\ 2NH_{4}HSO_{4}+Br_{2}+SO_{2}\uparrow +2H_{2}O}}

{\ displaystyle {\ mathsf {2NH_ {4} Br + 3H_ {2} SO_ {4} \ {\ xrightarrow {}} \ 2NH_ {4} HSO_ {4} + Br_ {2} + SO_ {2} \ uparrow + 2H_ {2} O}}}

Decomposed by alkalis:

{\mathsf {NH_{4}Br+NaOH\ {\xrightarrow {100^{o}C}}\ NH_{3}\uparrow +NaBr+H_{2}O}}

{\ displaystyle {\ mathsf {NH_ {4} Br + NaOH \ {\ xrightarrow {100 ^ {o} C}} \ NH_ {3} \ uparrow + NaBr + H_ {2} O}}}

Concentrated hot solution reacts with magnesium:

{\mathsf {2NH_{4}Br+Mg\ {\xrightarrow {}}\ MgBr_{2}+H_{2}\uparrow +2NH_{3}\uparrow }}

{\ displaystyle {\ mathsf {2NH_ {4} Br + Mg \ {\ xrightarrow {}} \ MgBr_ {2} + H_ {2} \ uparrow + 2NH_ {3} \ uparrow}}}

It is a weak reducing agent:

{\mathsf {NH_{4}Br+KNO_{2}\ {\xrightarrow {}}\ KBr+N_{2}\uparrow +2H_{2}O}}

{\ displaystyle {\ mathsf {NH_ {4} Br + KNO_ {2} \ {\ xrightarrow {}} \ KBr + N_ {2} \ uparrow + 2H_ {2} O}}}

Application

Medications.
Flame retardant .

Literature

Chemistry Handbook / Editorial: Nikolsky B.P. et al. - 2nd ed., rev. - M.-L.: Chemistry, 1966. - T. 1. - 1072 p.
Chemistry Handbook / Editorial: Nikolsky B.P. et al. - 3rd ed., rev. - L .: Chemistry, 1971. - T. 2. - 1168 p.
Lidin R.A. and other Chemical properties of inorganic substances: Textbook. manual for universities. - 3rd ed., Rev. - M .: Chemistry, 2000 .-- 480 p. - ISBN 5-7245-1163-0 .

Ammonium bromide


Are common
Systematic name	Ammonium bromide
Traditional names	Ammonium bromide
Chem. formula	NH ₄ Br
Physical properties
condition	colorless crystals
Molar mass	97.943 g / mol
Density	2,429 g / cm³
Thermal properties
T. decomp.	394 ° C
Chemical properties
Solubility in water	59.5 ⁰ ; 74.2 ²⁰ ; 119.3 ⁸⁰ ; 134.7 ¹⁰⁰ g / 100 ml
Optical properties
Refractive index	1,712
Classification
Reg. CAS number	12124-97-9
PubChem
Reg. EINECS number
Smiles
Inchi
RTECS	BO9155000
Chebi
ChemSpider