Oxide Germany (IV)

Germanium dioxide
Germanium dioxide
Are common
Systematic ; name	Oxide Germany (IV)
Abbreviations	ACC10380, G-15
Chem. formula	Ge o 2
Physical properties
condition	white powder, colorless crystals
Molar mass	104.61 g / mol
Density	4,228 g / cm³
Thermal properties
T. melt.	1116
T. Kip.	1200 ° C
Optical properties
Refractive index	1.7
Classification
Reg. CAS number	1310-53-8
Pubchem
Reg. EINECS number
SMILES
Inchi
RTECS	LY5240000
Chemspider

Germanium oxide (IV) ( germanium dioxide, germanium dioxide ) is a binary inorganic chemical compound of germanium with oxygen, is an amphoteric oxide . Chemical formula GeO ₂ .

Structure

The forms of germanium dioxide are very similar to silicon dioxide . It exists in the form of two crystal modifications and the third - amorphous:

Hexagonal β -GeO ₂ has the same structure as α - quartz , germanium has a coordination number 4, the space group P3 ₁ 21 or P3 ₂ 21, the unit cell parameters: a = 0.4972 nm, c = 0.5648 nm, Z = 3 d ₂₀ = 4.70 g / cm³.
Tetragonal α -GeO ₂ (the mineral form is argutite ( English argutite )) has a structure like SnO ₂ , germanium has a coordination number of 6, unit cell parameters: a = 0.4395 nm, c = 0.2860 nm, d ₂₀ = 6 , 24 g / cm ³. Under high pressure goes into rhombic form , the structure of the type CaCl ₂ . ^[2] .
Amorphous GeO ₂ is similar to glassy quartz , soluble in water. ( a = 0.4987 nm, c = 0.5652 nm; consists of slightly distorted tetrahedra with a germanium atom in the center) ^[3] .

Tetragonal germanium dioxide at 1033 ° C becomes hexagonal. Δ H _{α → β} = 21.6 kJ / mol .

**Some properties of germanium dioxide**
Indicator	Crystal modification		Vitreous GeO ₂
Indicator	α	β	Vitreous GeO ₂
T. _pl. ° C	1086	1115	-
Tight g / cm³	6.277	4.28	3,667
K ⁻¹	5.36⋅10 ⁻⁵ (298–698 K)	9.5⋅10 ⁻⁶ (298–798 K)	7.5⋅10 ⁻⁶ (298–698 K)
Δ H _pl. , kJ / mol	21.1	17.6	-
S ° ₂₉₈ , J / (mol · K)	39.71	55.27	69.77
С ° _p , J / (mol · K)	50.17	52.09	53
Δ H _arr. , kJ / mol	-580.15	-554,71	-539.00

Getting

Get germanium dioxide by hydrolysis of GeCl ₄ followed by drying and calcining the precipitate at 900 ° C. A mixture of amorphous and hexagonal GeO ₂ is usually formed.

{\mathsf {GeCl_{4}+H_{2}O\longrightarrow {\mathit {m}}GeO_{2}\cdot {\mathit {n}}H_{2}O+4HCl\uparrow {\xrightarrow {900~^{\circ }{\text{C}}}}GeO_{2}+H_{2}O\uparrow }}

{\ displaystyle {\ mathsf {GeCl_ {4} + H_ {2} O \ longrightarrow {\ mathit {m}} GeO_ {2} \ cdot {\ mathit {n}} H_ {2} O + 4HCl \ uparrow {\ xrightarrow {900 ~ ^ {\ circ} {\ text {C}}}} GeO_ {2} + H_ {2} O \ uparrow}}}

At temperatures above 700 ° C, germanium dioxide is produced by the oxidation of germanium:

{\mathsf {Ge+O_{2}{\xrightarrow {>700~^{\circ }{\text{C}}}}GeO_{2}}}

{\ displaystyle {\ mathsf {Ge + O_ {2} {\ xrightarrow {> 700 ~ ^ {\ circ} {\ text {C}}}} GeO_ {2}}}}

Hydrolysis of germanium (IV) sulfide in boiling water :

{\mathsf {GeS_{2}+2H_{2}O{\xrightarrow {100~^{\circ }{\text{C}}}}GeO_{2}\downarrow +2H_{2}S\uparrow }}

{\ displaystyle {\ mathsf {GeS_ {2} + 2H_ {2} O {\ xrightarrow {100 ~ ^ {\ circ} {\ text {C}}} GeO_ {2} \ downarrow + 2H_ {2} S \ uparrow}}}

Dissolving germanium in dilute nitric acid :

{\mathsf {Ge+4HNO_{3}\longrightarrow GeO_{2}\downarrow +4NO_{2}\uparrow +2H_{2}O}}

{\ displaystyle {\ mathsf {Ge + 4HNO_ {3} \ longrightarrow GeO_ {2} \ downarrow + 4NO_ {2} \ uparrow + 2H_ {2} O}}}

By oxidation of germanium (II) sulfide with concentrated hot nitric acid :

{\mathsf {GeS+10HNO_{3}\longrightarrow GeO_{2}\downarrow +H_{2}SO_{4}+10NO_{2}\uparrow +4H_{2}O}}

{\ displaystyle {\ mathsf {GeS + 10HNO_ {3} \ longrightarrow GeO_ {2} \ downarrow + H_ {2} SO_ {4} + 10NO_ {2} \ uparrow + 4H_ {2} O}}}

Hydrolysis or oxidation of germanium hydrogen:

{\mathsf {GeH_{4}+2H_{2}O{\xrightarrow {~T~}}GeO_{2}\downarrow +4H_{2}\uparrow }}

{\ displaystyle {\ mathsf {GeH_ {4} + 2H_ {2} O {\ xrightarrow {~ T ~}} GeO_ {2} \ downarrow + 4H_ {2} \ uparrow}}}

{\mathsf {GeH_{4}+2O_{2}{\xrightarrow {200~^{\circ }{\text{C}}}}GeO_{2}+2H_{2}O}}

{\ displaystyle {\ mathsf {GeH_ {4} + 2O_ {2} {\ xrightarrow {200 ~ ^ {\ circ} {\ text {C}}}} GeO_ {2} + 2H_ {2} O}}}

Destruction of germanates by dilute nitric acid :

{\mathsf {Na_{2}GeO_{3}+2HNO_{3}\longrightarrow GeO_{2}\downarrow +2NaNO_{3}+H_{2}O}}

{\ displaystyle {\ mathsf {Na_ {2} GeO_ {3} + 2HNO_ {3} \ longrightarrow GeO_ {2} \ downarrow + 2NaNO_ {3} + H_ {2} O}}}

Chemical Properties

α -GeO ₂ and amorphous GeO _{2 are} chemically more passive, therefore chemical properties are described for β- GeO ₂ .

Heating germanium dioxide at 1000 ° C gives germanium oxide (GeO) ^[3] :

{\mathsf {2GeO_{2}\rightleftarrows 2GeO+O_{2}}}

{\ displaystyle {\ mathsf {2GeO_ {2} \ rightleftarrows 2GeO + O_ {2}}}

It is reduced by hydrogen and carbon to metallic germanium when heated:

{\mathsf {GeO_{2}+2H_{2}{\xrightarrow {600~^{\circ }{\text{C}}}}Ge+2H_{2}O}}

{\ displaystyle {\ mathsf {GeO_ {2} + 2H_ {2} {\ xrightarrow {600 ~ ^ {\ circ} {\ text {C}}}} Ge + 2H_ {2} O}}}

{\mathsf {GeO_{2}+C{\xrightarrow {500{-}600~^{\circ }{\text{C}}}}Ge+CO_{2}}}

{\ displaystyle {\ mathsf {GeO_ {2} + C {\ xrightarrow {500 {-} 600 ~ ^ {\ circ} {\ text {C}}}} Ge + CO_ {2}}}}

Germanium dioxide is soluble in water, forming a weak metagermanic acid :

{\mathsf {GeO_{2}+H_{2}O\longrightarrow H_{2}GeO_{3}}}

{\ displaystyle {\ mathsf {GeO_ {2} + H_ {2} O \ longrightarrow H_ {2} GeO_ {3}}}}

{\mathsf {H_{2}GeO_{3}+H_{2}O\rightleftarrows HGeO_{3}^{-}+H_{3}O^{+}}};\quad pK=8{,}73

{\ displaystyle {\ mathsf {H_ {2} GeO_ {3} + H_ {2} O \ rightleftarrows HGeO_ {3} ^ {-} + H_ {3} O ^ {+}}}; \ quad pK = 8 { ,} 73}

{\mathsf {HGeO_{3}^{+}+H_{2}O\rightleftarrows GeO_{3}^{2+}+H_{3}O^{+}}};\quad pK=12{,}72

{\ displaystyle {\ mathsf {HGeO_ {3} ^ {+} + H_ {2} O \ rightleftarrows GeO_ {3} ^ {2 + + H_ {3} O ^ {+}}}; \ quad pK = 12 {,} 72}

It dissolves in alkalis, forms diluted metagermanic acid salts with dilute, orthogermanic: with concentrated salts:

{\mathsf {GeO_{2}+2NaOH{\xrightarrow {<20\,\%}}Na_{2}GeO_{3}+H_{2}O}}

{\ displaystyle {\ mathsf {GeO_ {2} + 2NaOH {\ xrightarrow {<20 \, \%}} Na_ {2} GeO_ {3} + H_ {2} O}}}

{\mathsf {GeO_{2}+2NaOH+2H_{2}O{\xrightarrow {>20\,\%}}Na_{2}[Ge(OH)_{6}]}}

{\ displaystyle {\ mathsf {GeO_ {2} + 2NaOH + 2H_ {2} O {\ xrightarrow {> 20 \, \%}} Na_ {2} [Ge (OH) _ {6}]}}

Germanium gray nitride (Ge ₃ N ₄ ) can be obtained by the action of NH ₃ on metallic germanium (or GeO ₂ ) at 700 ° C ^[4] :

{\mathsf {4NH_{3}+3GeO_{2}{\xrightarrow {700~^{\circ }{\text{C}}}}Ge_{3}N_{4}+6H_{2}O}}

{\ displaystyle {\ mathsf {4NH_ {3} + 3GeO_ {2} {\ xrightarrow {700 ~ ^ {\ circ} {\ text {C}}} Ge_ {3} N_ {4} + 6H_ {2} O }}}

Interacts with hydrogen halide:

{\mathsf {GeO_{2}+4HCl{\xrightarrow {450~^{\circ }{\text{C}}}}GeCl_{4}+2H_{2}O}}

{\ displaystyle {\ mathsf {GeO_ {2} + 4HCl {\ xrightarrow {450 ~ ^ {\ circ} {\ text {C}}}} GeCl_ {4} + 2H_ {2} O}}}

When heated, it destroys salts of weaker acids with the formation of germanates :

{\mathsf {GeO_{2}+Na_{2}CO_{3}{\xrightarrow {1200~^{\circ }{\text{C}}}}Na_{2}GeO_{3}+CO_{2}}}

{\ displaystyle {\ mathsf {GeO_ {2} + Na_ {2} CO_ {3} {\ xrightarrow {1200 ~ ^ {\ circ} {\ text {C}}}} Na_ {2} GeO_ {3} + CO_ {2}}}}

With oxides of alkali metals, depending on their quantity, it forms various germanates:

{\mathsf {GeO_{2}+{\mathit {x}}~Na_{2}O{\xrightarrow {1000~^{\circ }{\text{C}}}}Na_{2}GeO_{3},Na_{6}GeO_{5},Na_{4}GeO_{4}}}

{\ displaystyle {\ mathsf {GeO_ {2} + {\ mathit {x}} ~ Na_ {2} O {\ xrightarrow {1000 ~ ^ {{circ} {\ text {C}}}} Na_ {2} GeO_ {3}, Na_ {6} GeO_ {5}, Na_ {4} GeO_ {4}}}}

Application

Germanium dioxide is an intermediate in the production of pure germanium and its compounds.

Germanium dioxide has a refractive index of ~ 1.7, which allows it to be used as an optical material for wide-angle lenses and in lenses of lenses of optical microscopes . Transparent in the infrared range of the spectrum.

A mixture of silicon dioxide and germanium dioxide is used as a material for optical fibers ^[5] . Changing the ratio of components allows you to accurately control the refraction of light. Germanium dioxide allows to replace titanium dioxide as a dopant, which eliminates the need for subsequent heat treatment, which makes the fiber brittle. ^[6]

Germanium dioxide is also used as a catalyst in the production of polyethylene terephthalic resin ^[7] .

Used as a raw material for the production of some phosphors and semiconductor materials.

Toxicity

Germanium dioxide has low toxicity , but at higher doses it is nephrotoxin . Germanium dioxide is used in some dietary supplements ^[8] .

Notes

↑ ¹ ² The most important compounds of germanium (Neopr.) . The appeal date is April 16, 2010. Archived April 2, 2007.
↑ Structural evolution of the rutile-type and CaCl ₂ -type germanium dioxide at high pressure, J. Haines, JM Léger, C. Chateau, AS Pereira, Physics and Chemistry of Minerals, 27, 8, (2000), 575-582, DOI : 10.1007 / s002690000092 .
↑ ¹ ² Greenwood, Norman N .; Earnshaw, A. (1997), Chemistry of the Elements (2nd ed.), Oxford: Butterworth-Heinemann, ISBN 0-08-037941-9 .
↑ Chemistry, elements of the periodic table (rus.) Document 12, page 17. Circulation date is May 14, 2010. Archived on April 23, 2012.
↑ Robert D. Brown, Jr. GERMANIUM ( op .) . US Geological Survey (2000). The appeal date is April 16, 2010. Archived on August 22, 2011.
↑ Chapter Iii: Optical Fiber For Communications (Unreferenced) (inaccessible link) . The appeal date is April 16, 2010. Archived June 15, 2006.
Ie,,, Status Ul Ul Ul eth eth eth eth eth eth eth eth ( ylene Poly Poly // // // // // // // // // // // // // // ) // International Journal of Polymeric Materials: journal. - 2001. - Vol. 50 , no. 3 - p. 387 - 394 . - DOI : 10.1080 / 00914030108035115 .
↑ Tao, S. H .; Bolger, P. M. Hazard Assessment of Germanium Supplements (Eng.) // Regulatory Toxicology and Pharmacology : journal. - 1997. - June ( vol. 25 , no. 3 ). - P. 211-219 . - DOI : 10.1006 / rtph.1997.1098 .

Links

Germany dioxide on the site XuMuK.ru

Germanium compound classes

► Compounds Germany

[Соединения_германия-1] ¹ ² The most important compounds of germanium (Neopr.) . The appeal date is April 16, 2010. Archived April 2, 2007.

[2] Structural evolution of the rutile-type and CaCl ₂ -type germanium dioxide at high pressure, J. Haines, JM Léger, C. Chateau, AS Pereira, Physics and Chemistry of Minerals, 27, 8, (2000), 575-582, DOI : 10.1007 / s002690000092 .

[Greenwood-3] ¹ ² Greenwood, Norman N .; Earnshaw, A. (1997), Chemistry of the Elements (2nd ed.), Oxford: Butterworth-Heinemann, ISBN 0-08-037941-9 .

[4] Chemistry, elements of the periodic table (rus.) Document 12, page 17. Circulation date is May 14, 2010. Archived on April 23, 2012.

[Brown-5] Robert D. Brown, Jr. GERMANIUM ( op .) . US Geological Survey (2000). The appeal date is April 16, 2010. Archived on August 22, 2011.

[6] Chapter Iii: Optical Fiber For Communications (Unreferenced) (inaccessible link) . The appeal date is April 16, 2010. Archived June 15, 2006.

[Thiele-7] Ie,,, Status Ul Ul Ul eth eth eth eth eth eth eth eth ( ylene Poly Poly // // // // // // // // // // // // // // ) // International Journal of Polymeric Materials: journal. - 2001. - Vol. 50 , no. 3 - p. 387 - 394 . - DOI : 10.1080 / 00914030108035115 .

[8] Tao, S. H .; Bolger, P. M. Hazard Assessment of Germanium Supplements (Eng.) // Regulatory Toxicology and Pharmacology : journal. - 1997. - June ( vol. 25 , no. 3 ). - P. 211-219 . - DOI : 10.1006 / rtph.1997.1098 .

Germanium dioxide

Are common
Systematic name	Oxide Germany (IV)
Abbreviations	ACC10380, G-15
Chem. formula	Ge o ₂
Physical properties
condition	white powder, colorless crystals
Molar mass	104.61 g / mol
Density	4,228 g / cm³
Thermal properties
T. melt.	1116 ^[1]
T. Kip.	1200 ^[1] ° C
Optical properties
Refractive index	1.7
Classification
Reg. CAS number	1310-53-8
Pubchem
Reg. EINECS number
SMILES
Inchi
RTECS	LY5240000
Chemspider