Sodium Metaphosphate

Sodium Metaphosphate
Sodium Metaphosphate
General
Systematic ; name	Sodium Metaphosphate
Traditional names	Sodium Phosphate
Chem. formula	NaPO 3
Physical properties
Molar mass	101.96 g / mol
Density	2,476; 2.65 ÷ 2.62 g / cm³
Thermal properties
T. melt.	619; 627.6; 630-650 ° C
Chemical properties
Solubility in water	97.32 25 ; 174.4 80 g / 100 ml
Classification
Reg. CAS number
PubChem
Reg. EINECS number
Smiles
Inchi
ChemSpider

Sodium metaphosphate is an inorganic compound, a salt of an alkali metal of sodium and metaphosphoric acid with the formula NaPO ₃ , white amorphous or crystalline, soluble in water. It is a polymer of Na _n (PO ₃ ) _n , where n = 1000 ÷ 10000. Oligomers with n = 3 and 4 were isolated; they form crystalline hydrates .

Content

1 Receiving
2 Physical properties
3 Chemical properties
4 Literature

Getting

Neutralization of metaphosphoric acid with sodium hydroxide . At 0 ° С oligomers are obtained, at 500-600 ° С - polymers:

{\mathsf {HPO_{3}+NaOH\ {\xrightarrow {}}\ NaPO_{3}+H_{2}O}}

{\ displaystyle {\ mathsf {HPO_ {3} + NaOH \ {\ xrightarrow {}} \ NaPO_ {3} + H_ {2} O}}}

Effect on heating of phosphoric acid on sodium salts:

{\mathsf {H_{3}PO_{4}+NaCl\ {\xrightarrow {400-500^{o}C}}\ NaPO_{3}+HCl+H_{2}O}}

{\ displaystyle {\ mathsf {H_ {3} PO_ {4} + NaCl \ {\ xrightarrow {400-500 ^ {o} C}} \ NaPO_ {3} + HCl + H_ {2} O}}}

Decomposition of sodium dihydrogen phosphate :

{\mathsf {NaH_{2}PO_{4}\ {\xrightarrow {220-250^{o}C}}\ NaPO_{3}+H_{2}O}}

{\ displaystyle {\ mathsf {NaH_ {2} PO_ {4} \ {\ xrightarrow {220-250 ^ {o} C}} \ NaPO_ {3} + H_ {2} O}}}

Decomposition of sodium dihydrogen diphosphate :

{\mathsf {Na_{2}H_{2}P_{2}O_{7}\ {\xrightarrow {220-250^{o}C}}\ 2NaPO_{3}+H_{2}O}}

{\ displaystyle {\ mathsf {Na_ {2} H_ {2} P_ {2} O_ {7} \ {\ xrightarrow {220-250 ^ {o} C}} \ 2NaPO_ {3} + H_ {2} O} }}

Physical Properties

Sodium metaphosphate forms a white amorphous or crystalline powder.

Oligomers form crystalline hydrates Na ₃ P ₃ O ₉ • 6H ₂ O, Na ₄ P ₄ O ₁₂ • 4H ₂ O.

Chemical Properties

With hot water forms various acid salts:

{\mathsf {NaPO_{3}\ {\xrightarrow {H_{2}O,100^{o}C}}\ Na_{3}H_{2}P_{3}O_{10},Na_{2}H_{2}P_{2}O_{7},NaH_{2}PO_{4}}}

{\ displaystyle {\ mathsf {NaPO_ {3} \ {\ xrightarrow {H_ {2} O, 100 ^ {o} C}} \ Na_ {3} H_ {2} P_ {3} O_ {10}, Na_ { 2} H_ {2} P_ {2} O_ {7}, NaH_ {2} PO_ {4}}}}

With a hot alkaline solution forms various sodium phosphates:

{\mathsf {NaPO_{3}\ {\xrightarrow {NaOH,40-100^{o}C}}\ Na_{3}P_{3}O_{9},Na_{3}PO_{4},Na_{5}P_{3}O_{10},Na_{4}P_{2}O_{7},Na_{6}P_{4}O_{13}}}

{\ displaystyle {\ mathsf {NaPO_ {3} \ {\ xrightarrow {NaOH, 40-100 ^ {o} C}} \ Na_ {3} P_ {3} O_ {9}, Na_ {3} PO_ {4} , Na_ {5} P_ {3} O_ {10}, Na_ {4} P_ {2} O_ {7}, Na_ {6} P_ {4} O_ {13}}}}

It enters into metabolic reactions:

{\mathsf {NaPO_{3}+AgNO_{3}\ {\xrightarrow {}}\ AgPO_{3}\downarrow +NaNO_{3}}}

{\ displaystyle {\ mathsf {NaPO_ {3} + AgNO_ {3} \ {\ xrightarrow {}} \ AgPO_ {3} \ downarrow + NaNO_ {3}}}}

Literature

Chemical Encyclopedia / Editorial: Zefirov N.S. et al. - M .: Big Russian Encyclopedia, 1998. - V. 5. - 783 p. - ISBN 5-85270-310-9 .
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 .