Английская Википедия:Arsenate arsenite

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Файл:Halilsarpite.jpg

Yellow spherules of halilsarpite, an arsenate arsenite mineral, on orange-brown smolyaninovite

An arsenate arsenite is a chemical compound or salt that contains arsenate and arsenite anions (AsO₃^3- and AsO₄^3-). These are mixed anion compounds or mixed valence compounds. Some have third anions. Most known substances are minerals, but a few artificial arsenate arsenite compounds have been made. Many of the minerals are in the Hematolite Group.

An arsenate arsenite compound may also be called an arsenite arsenate.

Properties

Some members of this group of materials like mcgovernite has an extremely high unit cell dimension of 204 Å.

Related

Mixed valence pnictide compounds related to the arsenate arsenites include the nitrite nitrates, and phosphate phosphites.

List

name	formula	ratio AsO4:AsO3	system	space group	unit cell Å	volume	density	properties	references
Arsenic dioxide	AsO2	1:1	orthorhomnic	Pnma	a=8.597 b=5.235 c=7.269 Z=8	327.1	4.382
Arsenic(III) Arsenic(V) Oxide Hydroxide	As3O5(OH)	1:2	monoclinic	P21/c	a = 12.504 b = 4.593 c = 10.976 β = 118.08° Z = 4	556.2	3.84
	H6As3+7As5+7O31	1:1	hexagonal	P63	a = 12.0525 c = 4.7344 Z = 2	595.6
Segerstromite	Ca3(As5+O4)2[As3+(OH)3]2	2:1	cubic	I213	a = 10.7627 Z = 4	1246.71	3.46	colourless; refract index: n = 1.731
Synadelphite	Mn2+9(As5+O4)2(As3+O3)(OH)9 · 2H2O	2:1	Orthorhombic	Pnma	a = 10.75 b = 18.86c = 9.88 Z=4	2005	3.58	red; Biaxial (+); refract index: nα = 1.750 - 1.870 nβ = 1.751 - 1.880 nγ = 1.761 - 1.930
Hematolite	(Mn,Mg,Al,Fe3+)15(As5+O4)2(As3+O3)(OH)23	2:1	trigonal	RШаблон:Overbar	a = 8.275 Å, c = 36.60 Å Z=3	2,170.4	3.49	deep red; Uniaxial (-) refractive index nω = 1.733 nε = 1.714; Birefringence: 0.019
Turtmannite	(Mn,Mg)22.5Mg3-3x((V5+,As5+)O4)3(As3+O3)x(SiO4)3O5-5x(OH)20+x		trigonal		a = 8.259 c = 204.3 Z=12	12,068	3.8	light yellow; Uniaxial (-); refractive index: nε = 1.787
Carlfrancisite	Mn2+3(Mn2+,Mg,Fe3+,Al)42[As3+O3]2(As5+O4)4[(Si,As5+)O4]6[(As5+,Si)O4]2(OH)42		trigonal	RШаблон:Overbarc	a = 8.2238 c = 205.113 Z=6	12,013.5	3.620	yellow-orange; Uniaxial (+) refractive index: nω = 1.756(2) nε = 1.758 Birefringence: δ = 0.002
	K2Cu3(As2O6)2	1:1	monoclinic	C2m	a=10.359 b=5.388 c=11.234 β=110.48°			[As(V)As(III)O6]4−
Dixenite	CuMn2+14Fe2+(SiO4)2(As5+O4)(As3+O3)5(OH)6	1:5	trigonal	R3	a = 8.233 c = 37.499 Z=3	2201	4.35	deep red-brown; Uniaxial (+) refractive index nω = 1.970 nε = 1.730
Arakiite	(Zn,Mn2+)(Mn2+,Mg)12(Fe3+,Al)2(As5+O4)2(As3+O3)(OH)23	2:1	monoclinic	Cc	a = 14.248 b = 8.228 c = 24.23 β = 93.62° Z=4	2843	3.41	orange-red brown; Biaxial (-); refract index: nα = 1.723 nβ = 1.744 nγ = 1.750 Birefringence: 0.027
Kraisslite	Zn3(Mn,Mg)25(Fe3+,Al)(As3+O3)2[(Si,As5+)O4]10(OH)16	5:1	Orthorhombic	C2221	a = 8.1821 b = 14.1946 c = 43.9103 Z=4	5099.8	3.876	pale red; Uniaxial (+) Refractive index: nε = 1.805
Mcgovernite	Mn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21	3:1	trigonal	R3m or RШаблон:Overbarm	a = 8.22 c = 203.1 Z=6	11,887.52	3.719	brown; Uniaxial (+) Refractive index: nω = 1.757 nε = 1.760 Birefringence: δ = 0.003
Halilsarpite	[Mg(H2O)6][CaAs3+2(Fe3+2.67Mo6+0.33)(AsO4)2O7]		orthorhomnic	Imma	a = 26.489 b = 7.4205 c = 10.4378	2051.7		lemon yellow; Biaxial (-) refractive index: nα = 1.646 nβ = 1.765(5) nγ = 1.815(5) 2V: 62° Max Birefringence: δ = 0.169
Wiklundite	Pb2(Mn2+,Zn)3(Fe3+,Mn2+)2(Mn2+,Mg)19(As3+O3)2[(Si,As5+)O4]6(OH)18Cl6		hexagonal	? RШаблон:Overbarc	a = 8.257 c = 126.59 Z = 6	7474	4.072	dark reddish brown
	Bi8O6(AsO3)2(AsO4)2		monoclinic	I2/a	a=24.372 b=5.528 c=29.90 β=99.058 Z=8	3978	7.652	colourless
	Th(AsIII4AsV4O18)	1:1	monoclinic	C2/c	a=18.2148 b 5.19792 c=17.3588 β=99.1298 Z=4	1622.70	4.582	colourless