Borophosphate

The borophosphates are mixed anion compounds containing borate and phosphate anions, which may be joined together by a common oxygen atom. Compounds that contain water or hydroxy groups can also be included in the class of compounds.^[1]

Borophosphates can be classified by whether or not they are hydrated, and the anion structure, which can be single, double, triple, isolated ring, isolated branched ring, simple chain, branched chain, loop chain, layers, or three-dimensional network.^[1] The isolated anion compounds are the borate phosphates, which contain separate borate and phosphate groups. Some of the borophosphate structures resemble silicates.^[1]

Related compounds include aluminophosphates, which have aluminium instead of boron, gallophosphates,^[2] with gallium in place of boron, and by substituting the phosphate: boroarsenates, boroantimonates, and vanadoborates.

Formation

Borophosphates can be formed by heating compounds together at up to 900 °C. The products are dense, anhydrous, and do not contain organic substances.^[2]

Solvothermal synthesis uses a non water solvent such as ethylene glycol to dissolve the product.^[2]

The flux method crystallises from a molten flux of boric acid and sodium dihydrogen phosphate at around 171.^[3]

The hydrothermal method heats the ingredients with water under pressure up to 200 °C. The ingredients are boric acid, phosphoric acid, metal salts, or organic bases. Products often contain hydrogen.^[2]

The ionothermal synthesis method uses an ionic liquid such as 1-alkyl-3-methylimidazolium bromide as a solvent. This can be done at atmospheric pressure and temperatures under 100 °C.^[2]

Characteristics

Borophosphate compounds have been investigated for magnetic, electrical, optical and catalytic properties. Some borophosphates are porous and so have surface for interaction on their interiors, not just their surface. They can reversibly absorb water, or have channels that can allow ions to conduct. The reflection of a labelled tetrahedron cannot be superimposed (even with rotation or movements), so the compounds containing phosphate and borate tetrahedrons can be non-centrosymmetric, or chiral.^[2]

List

name	formula	crystal system	space group	unit cell Å	volume	density	comment	refs
	Li[B3PO6(OH)3]						looped chain B3O3 rings OH on B and P	[1]
	Li2B3PO8		P1					[2]
	Li3BP2O8		P1					[2]
	NH4BeBP2O8·⁠1/3⁠H2O	cubic	P213				zeolite-ANA structure	[4]
	(NH4)2[B3PO7(OH)2]						looped chain B3O3 rings OH on B	[1]
	(NH4)2B2P3O11(OH)	monoclinic	P21/c	a=15.774 b=7.5213 c=8.9661 β=106.93° Z=4	1020.0	2.238		[5]
	(NH4)2B2P3O11(OH)	orthorhombic	P212121	a=4.509 b = 14.49 c = 16.40 Z=4	1072	2.130	colourless	[6]
	(NH4)3H2[BOB(PO4)3]						infinite chains	[7]
	(NH4)4[H2B2P4O16]	tetragonal	P41212					[2]
	(NH4)2BP2O7(OH)	tetragonal	P41212	a=7.2162 c=14.8258 Z=4	772.03	2.046		[5]
	Na2[BP2O7(OH)]	orthorhombic	Pna21	a=6.8236, b=20.7911, c=13.1446, Z=12			layers	[8]
	Na3B6PO13	orthorhombic	Pnma	a=9.3727, b=16.2307, c=6.7232, Z=4			8 member rings	[3]
	Na3BP2O8	monoclinic	C2/c	a=12.567, b=10.290, c=10.210, β=92.492, Z=2			infinite chains	[3]
	Na5[BOB(PO4)3)]						infinite chains	[7]
	NaBeBP2O8·⁠1/3⁠H2O	cubic	P213				zeolite-ANA structure	[4]
	Na13(H2O)2[B6P11O42(OH)2]Cl2·H2O		F23					[2]
	MgBPO4(OH)2		P3121					[2]
dimagnesium (monohydrogen­monophosphate­dihydrogenmonoborate­monophosphate)	Mg2[BP2O7(OH)3]	triclinic	P1	a=6.452, b=6.455, c=8.360, α=82.50, β=82.56, γ=80.98, Z=1	338.8		triple	[9]
	(H3O)Mg(H2O)2[BP2O8]·H2O		P6122					[2]
	Mg3(H2O)6(B(OH)3PO4)2						double	[1]
	LiMg(H2O)2[BP2O8]·H2O		P6522					[2]
	NaMg(H2O)2[BP2O8]•H2O	hexagonal	P6122	a=9.428, c=15.820			loop branched chain	[10]
	Na2[MgB3P2O11(OH)]·⁠2/3⁠H2O	hexagonal	P63	a=11.771, c=12.100, Z=6		2.537	colourless	[11]
	Na3[Al2B6P4O22(OH)3](H2O)6	orthorhombic	Cmca	a=6.9493 b=14.5529 c=24.027				[12]
	Na3[Al2BP2O11](H2O)0.5	cubic	I23	a=19.7822				[12]
	K2B2P2O9	orthorhombic	P212121	a=7.8227 b=8.1393 c=12.925 Z=4	822.9	2.468		[5]
	K2BP2O7(OH)	orthorhombic	P212121	a=7.068 b=7.2396 c=14.116 Z=4	722.3	2.574		[5]
	K3B4PO10	triclinic	P1	a=6.546, b=6.567, c=12.930, α=86.04, β=81.40, γ=60.42, Z=2	477.9	2.443	colourless 2D sheet	[13]
	K7B2P5O19							[2]
	K3[B5PO10(OH)3]						loop branch	[1]
	LiK2BP2O8		P21/n					[2]
	Li3K2BP4O14		Cmca					[2]
	KBeBP2O8·⁠1/3⁠H2O	cubic	P213	a=12.427, Z=12	1,919		zeolite-ANA structure	[4]
	K2Na3B2P3O13	orthorhombic	Cmc21	a = 13.924 b = 6.7673 c = 12.130 Z = 4			B2P3O13 chain	[14]
	KMg(H2O)2[BP2O8]•H2O	hexagonal	P6122	a=9.463, c=15.815			loop branched chain	[10]
	Ca[BPO5]						loop branch B2PO3 rings	[1]
	Sc(H2O)2[BP2O8]·H2O	hexagonal	P6522	a=9.5752, c=15.8145, Z=6	1,255.7	2.378		[15]
	Sc(H2O)2[BP2O8]	hexagonal	P6522	a=9.535, c=15.768, Z=6				[15]
	NaSc[BP2O6(OH)3]·HPO4		P21/c					[2]
	Ti[BP2O7(OH)3]		I41/amd					[2]
	V2[B(PO4)3]							[16]
	(VO)2BP2O10							[17]
	Li3V2[BP3O12(OH)][HPO4]		P21/c					[2]
	Na2[VB3P2O12(OH)]·2.92H2O		I-43m					[16]
	NH4VIII[BP2O8(OH)]	monoclinic	P21/c	a=9.425, b=8.269, c=9.697, β=102.26°, Z=4	738.5			[18]
	[ImH2]3.8(H3O)1.2[(VIVO)4(BO)2(PO4)5]·0.3H2O	monoclinic	C2/c	a=9.4737, b=22.144, c=17.219, β=105.936°, Z=4			layered	[19]
	[enH2]2[Na(VO)10B(O)2(OPO3H)2}5]·22.5H2O							[20]
	[trienH4]4H[NH4(VO)12{B(O)2(OPO3)2}6]·14H2O	orthorhombic	Pbca	a=21.45, b=16.315, c=29.65, Z=4	10378	1.920		[21]
	[trienH4]4H[K(VO)12{O3POB(O)2OPO3}6]·16H2O	orthorhombic	Pbca	a=21.537, b=16.267, c=29.717, Z=4	10411	1.996		[21]
	KV[BP2O8(OH)]	triclinic	P1					[2]
	Cr2[B(PO4)3]		P63/m					[16]
	Na{Cr[BP2O7(OH)3]}	monoclinic	C2/c	a=10.4220, b=8.2468, c=9.2053, β=116.568°, Z=4	707.63			[22]
	Na8[Cr4B12P8O44(OH)4][P2O7]·nH2O		I23					[2]
	Na11K5[NaCr8B4P12O60H8]·H2O		Pmnn					[2]
	H2Mn5(H2O)6[BP2O8]4•4H2O	hexagonal	P6122	a=9.655, c=15.791, Z=1.5			pale pink	[23]
	Mn[BPO4(OH)2]		P3221	a=7.5750, c=12.927, Z=6	642.37	3.020		[24]
	LiMn(H2O)2[BP2O8(OH)]·H2O		P6522					[2]
	(NH4)Mn(H2O)2(BP2O8)·H2O		P6522	a = 9.6559, c = 15.7939	1275.3			[25]
	[NH4]4[Mn9B2(OH)2(HPO4)4(PO4)6]	monoclinic	C2/c	a=32.603, b=10.617, c=10.718, β=108.26°, Z=4	3523	2.971	light pink	[26]
	(NH4)6[Mn3B6P9O36(OH)3]·4H2O		C2					[2]
	(NH4)7Mn4(H2O)[B2P4O15(OH)2]2[H2PO4][HPO4]		Pnma					[2]
	(C3H12N2)[MnB2P3O12(OH)]							[2]
	(C4H12N2)[MnB2P3O12(OH)]		Ima2					[2]
	NaMn(H2O)2[BP2O8]•H2O	hexagonal	P6122	a=9.589, c=15.939			loop branched chain	[10]
	Na5(H3O){Mn3[B3O3(OH)]3(PO4)6}·2H2O	hexagonal	P63/m	a=11.9683, c=12.1303, Z=2				[27]
	Na5(NH4)Mn3[B9P2O33(OH)3]·⁠3/2⁠H2O		P63					[2]
	Na2[MnB3P2O11(OH)]·⁠2/3⁠H2O	hexagonal	P63	a=11.940, c=12.098, Z=6		2.670	colourless	[11]
	KMnBP2O7(OH)2	monoclinic	P21/c	a=6.659, b=12.049, c=9.790, β=109.12°, Z=4	742.2		orange-red luminescence	[28]
	KMn(H2O)2[BP2O8]•H2O	hexagonal	P6122	a=9.639, c=15.931			loop branched chain	[10]
	K5Mn2B2P5O19(OH)2		P21/n					[2]
	FeIII2[B(PO4)3]		P63/m					[16]
	Fe[B2P2O7(OH)5]	monoclinic	C2/c	a=17.745, b=6.720, c=7.059, β=109.01°, Z=4	796	2.808	unbranched chain	[1]
	Fe(H2O)2BP2O8·H2O	hexagonal		a=9.4583, c=15.707, Z=6	1216.9	2.543		[29]
	Fe[BPO4(OH)2]		P3221	a=7.4844, c=12.844, Z=6	623.06	3.129		[24]
	FeII(H2O)2[B2P2O8(OH)2]·H2O		P21/c					[2]
	Fe1.834IIFe0.166IIIB0.5[PO3(OH)]0.8(HPO3)2.033	cubic	I43d	a=21.261, Z=48				[30]
	NH4FeIII[BP2O8(OH)]	monoclinic	P21/c	a=9.393, b=8.285, c=9.689, β=102.07°, Z=4	737.4			[18]
	(NH4)0.75Fe(H2O)2[BP2O8]·⁠1/4⁠H2O		P6522					[2]
	(C3H12N2)[FeB2P3O12(OH)]		Ima2					[2]
	(C4H12N2)[FeB2P3O12(OH)]		Ima2					[2]
	(dienH3)(dienH2)0.5[FeII*III2B4P7O26(OH)4]		P1					[2]
	NaFe[BP2O7(OH)3]						triple
sodium diaquoiron(II) catena-[monoboro-diphosphate] monohydrate	NaFe(H2O)2[BP2O8]•H2O	hexagonal	P6122	a=9.499, c=15.931			loop branched chain	[10]
	Na2[FeB3P2O11(OH)]·⁠2/3⁠H2O	hexagonal	P63	a=11.812, c=12.067, Z=6		2.742	light yellow	[11]
potassium diaquoiron(II) catena-[monoboro-diphosphate] hemihydrate	KFe(H2O)2[BP2O8]•H2O	hexagonal	P6122	a=9.510, c=15.952			loop branched chain	[10]
	K2Fe2[B2P4O16(OH)2]	monoclinic	P21/c	a=9.372, b=8.146, c=9.587, β=101.18°, Z=2	718.0		B2P2O4 ring with phosphate sides	[31]
	KFeBP2O8(OH)		P21/c					[2]
	CaFe[BP2O7(OH)3]		C2/c					[2]
	Ca0.5Fe(H2O)2[BP2O8]·H2O		P6522					[2]
	Co5[BP3O14]						double + phosphate	[1]
	Co3[BPO7]	monoclinic	Cm	a=9.774, b=12.688, c=4.9057, β=119.749°, Z=4	528.2			[32]
	Co[BPO4(OH)2]		P3121	a=7.4554, c=12.7397, Z=6	613.24	3.229		[24]
	(NH4)7Co4(H2O)[B2P4O15(OH)2]2[H2PO4][HPO4]		Pnma					[2]
	(NH4)8[Co2B4P8O30(OH)4]		P1					[2]
	(NH4)Co(H2O)2(BP2O8)·H2O		P6122	a = 9.501 c = 15.582	1218.2			[25]
	CoII(H2O)2[B2P2O8(OH)2]·H2O		P21/c					[2]
	[Co(en)3][B2P3O11(OH)2]							[33]
	CoB2P3O12(OH)·H2en							[34]
	Co(C4H12N2)[B2P3O12(OH)]	orthorhombic	Ima2	a=12.4635, b=9.4021, c=11.4513, Z=4	1341.90			[35]
	H2Co5(H2O)6[BP2O8]4•4H2O	hexagonal	P6122	a=9.639, c=15.931, Z=1.5			purple
	LiCo(H2O)2[BP2O8]·H2O		P6522
	NaCo(H2O)2[BP2O8]•H2O	hexagonal	P6122	a=9.455, c=15.847			loop branched chain	[10]
	NaCoH2BP2O9	monoclinic	P21/c	a=6.547, b=11.404, c=9.650, β=107.37	687.6	2.905	pink; discovered in Tunisia	[36]
	Na2[CoB3P2O11(OH)]·⁠2/3⁠H2O	hexagonal	P63	a=11.759, c=12.099, Z=6		2.781	purple	[11]
	Na5(H3O){Co3[B3O3(OH)]3(PO4)6}·2H2O	hexagonal	P63/m	a=11.7691, c=12.112, Z=2				[27]
	Na6Co3B2P5O21Cl·H2O		Pnma
	KCo(H2O)2[BP2O8]•H2O	hexagonal	P6122	a=9.483, c=15.827			loop branched chain	[10]
	CaCo(H2O)[BP2O8(OH)]·H2O		P1					[2]
	(K0.17Ca0.42)Co(H2O)2[BP2O8]·H2O		P6522					[2]
	(Co0.6Mn0.4)2(H2O)[BP3O9(OH)4]		P212121					[2]
cobalt borophosphate ethylenediamine	CoB2P3O12(OH)·en	orthorhombic	Pbca	a=9.3501, b=12.2426, c=20.880	2,390.1	2.471	purple; layered	[37][38]
	(NH4)7Co4(H2O)[B2P4O15(OH)2]2[H2PO4][HPO4]	Orthorhombic	Pnma	a=16.9206, b=10.5592, c=22.000, Z=4	3,930.6	2.386	pink	[39]
	(NH4)2(C4H12N2)[Co2B4P6O24(OH)2]·H2O		I41/a					[2]
	NiBPO4(OH)2		P3121					[2]
	Ni(H2O)2[B2P2O8(OH)2]·H2O		P21/c					[2]
	LiNi(H2O)2[BP2O8]·H2O		P6522					[2]
	NaNi(H2O)2[BP2O8]•H2O	hexagonal	P6122	a=9.371, c=15.831			loop branched chain	[10]
	Na2[NiB3P2O11(OH)]·⁠2/3⁠H2O	hexagonal	P63	a=11.728, c=12.074, Z=6		2.799	yellow	[11]
	Na5(H3O){Ni3[B3O3(OH)]3(PO4)6}·2H2O	hexagonal	P63/m	a=11.7171, c=12.0759, Z=2				[27]
	KNi(H2O)2[BP2O8]•H2O	hexagonal	P6122	a=9.392, c=15.842			loop branched chain	[10]
	Cu3[B2P3O12(OH)3]	monoclinic	Cc	a=6.1895, b=13.6209, c=11.9373, β=97.62°, Z=4	997.5			[40]
	Cu(H2O)2[B2P2O8(OH)2]							[41]
	Cu2(H2O)[BP2O8(OH)]		Pbca					[2]
	LiCu2[BP2O8(OH)2]		C2/c					[2]
	LiCu2[BP2O8(OH)2]		P212121					[2]
	Na2[CuB3P2O11(OH)]·⁠2/3⁠H2O	hexagonal	P63	a=11.554, c=12.314, Z=6		2.862	sky-blue	[11]
	Na4Cu3[B2P4O15(OH)2]•2HPO4						ring with side phosphate and extra phosphate
	Na5KCu3[B9P6O33(OH)3]·H2O		P63/m					[2]
	Zn(C4H12N2)[B2P3O12(OH)]	orthorhombic	Ima2	a=12.4110, b=9.4550, c=11.4592, Z=4	1344.69			[35]
lithium zinc diaqua catena-[monoboro-diphosphate]-monohydrate	LiZn(H2O)2[BP2O8] · H2O	hexagonal	P61	a=9.469, c=15.667, Z=6	1216.6		spiral ribbons	[42]
	Na[ZnBP2O8]⋅H2O	hexagonal	P6122	a=9.5404, c=14.7780, Z=6	1164.88			[43]
	NaZn(H2O)2[BP2O8]•H2O	hexagonal	P6122	a=9.456, c=15.828			loop branched chain	[10]
	Na2[ZnB3P2O11(OH)]·⁠2/3⁠H2O	hexagonal	P63	a=11.963, c=12.363, Z=6		2.683	colourless	[11]
	NH4[ZnBP2O8]	triclinic	P1	a=7.437, b=7.612, c=7.850, α=119.05, β=101.59, γ=103.43, Z=2	351.18	2.687		[44]
	Na[ZnBP2O8]	triclinic	P1					[2]
	K[ZnBP2O8]	monoclinic	C2/c	a=12.617, b=12.773, c=8.415, β=91.25°, Z=8	1355.8	2.991		[44]
	[trienH4]1.5[Zn6B6P12O48]·⁠3/2⁠H2O	hexagonal	P6522	a=9.6685, c=14.8879; Z=1				[45]
RBPO	Rb3B11P2O23	Triclinic	P1	a=7.785, b=7.839, c=7.963, α=89,774, β=89.129, γ=88.211, Z=2	485.6	2.753	transparent above 168 nm; SHG 2.5× KDP; birefringence =0.071@1064 nm	[46]
	Rb[P2B2O8(OH)]						network	[1]
	Li3Rb2BP4O14		Cmca					[2]
	Rb3B11PO19F3	trigonal	R3	a=11.3715 c=12.0240 Z=3	1346.53	2.839	colourless; decompose > 470 °C; SHG 1.3 × KDP	[47]
	K2RbB4PO10	triclinic	P1	a=6.5577, b=6.5931, c=13.098, α=84.626, β=80.514, γ=60.457, Z=2	485.9	2.719	colourless	[13]
	K2RbB8PO16						birefringence 0.057@1064 nm	[48]
	K0.9Rb2.1B8PO16	monoclinic	Cc	a=11.3446 b=6.5485 c=19.354 β=101.315°	1409.9	2.761	birefringence 0.075@532 nm; band gap 6.16 eV;SHG 0.7 × KDP	[49]
	Rb2Co3(H2O)2[B4P6O24(OH)2]	orthorhombic	Pbca	a = 9.501, b = 12.272, c = 20.074, Z = 4				[50]
	Rb[ZnBP2O8]	triclinic	P1	a=7.439, b=7.639, c=7.861, α=118.82, β=101.73, γ=103.51, Z=2	353.4	3.304		[44]
	Sr[BPO5]		P3221				loop branch B2PO3 rings	[1]
	KSrBP2O8		I42d	a=7.109, c=13.882				[51]
	SrFe[BP2O8(OH)2]		C2/c					[2]
	SrCo2BPO7	monoclinic	P21/c	a=6.485, b=9.270, c=10.066, β=111.14, Z=4	548.7		red	[52]
	AgMg(H2O)2[BP2O8]·H2O		P6522					[2]
	⁠2/3⁠H2O		P6522					[2]
	(Ag0.57Ni0.22)Ni(H2O)2[BP2O8]·⁠2/3⁠H2O		P6522					[2]
	Na3Cd3BP4O16	orthorhombic	Pmc21	a=13.6854, b=5.335, c=18.2169, Z=4			SHG 1.1×KDP	[2][53]
	NH4Cd(H2O)2(BP2O8)·0.72H2O	hexagonal	P65	a=9.698, c=16.026, Z=6	1305.3	2.886	colourless	[54]
	In2[B(PO4)3]		P63/m					[16]
	Cs[P2B2O8(OH)]						3D network	[1]
	Li2Cs2B2P4O15
	K2CsB4PO10	triclinic	P1	a=6.6235, b=6.6243, c=13.273, α=79.734, β=86.558, γ=60.095, Z=2	496.46	2.979	colourless	[13]
	Cs2Cr3(BP4O14)(P4O13)	monoclinic	P21/c	a=14.7918, b=15.819, c=9.7037, β=92.450, Z=4	876.9	3.257	green; [B(P2O7)2]5−	[55]
	CsFe(BP3O11)	orthorhombic	Pnma	a=8.5375, b=12.7829, c=8.3346, Z=4	909.59	3.434	[N(PO4)(P2O7)]4-	[55]
	Cs2Co3(H2O)2[B4P6O24(OH)2]	orthorhombic	Pbca	a=9.5526, b=12.3190, c=20.1123	2366.8		pink	[2][56]
	Cs[ZnBP2O8]	triclinic	P1	a=7.506, b=7.914, c=8.038, α=1198.05, β=102.96, γ=104.50, Z=2	373.9	3.545		[44]
	Ba[BPO5]		P3221					[2]
	Ba[BP3O12]	orthorhombic	Ibca	a=7.066, b=14.268, c=22.159	2233.9	4.209		[1][57]
	BaB2P2O8F2	monoclinic	P21/n	a=4.4719 b=20.499 c=7.8896 β=92.955° Z=4	722.3	3.558	birefringence 0.007 @ 532 nm
	KBaBP2O8		I42d	a=7.202, c=14.300				[51]
	BaFe[BP2O8(OH)]		P1					[2]
	BaCo[BP2O8(OH)]		P1					[2]
	Pb[BPO5]						loop branch B2PO3 rings	[1]
	Pb3[(PO4)2BPO4]	orthorhombic	Pbca	a=6.946, b=14.199, c=21.116, Z=8	2082.5	5.851	open branch, 2 PO4 extra on each B	[57]
	Na3PbII[B(O3POH)4]		I41/a					[2]
	KPbBP2O8		I42d					[2]
	PbII4Cl{Co2[B(OH)2P2O8](PO4)2]}		R3c					[2]
	RbPbBP2O8		I42d					[2]
	BiCo2BP2O10		P21/m					[2]
	BiNi2BP2O10		P21/m					[2]
	K2(UO2)12[B(H2PO4)4](PO4)8(OH)(H2O)6	tetragonal	I42m	a=21.8747, c=7.0652	3380.7			[58]
	K5(UO2)2[B2P3O12(OH)]2(OH)(H2O)2	monoclinic	P21	a=6.7623, b=19.5584, c=11.0110, β=95.579°	1449.42			[58]
	Ag2(NH4)3{(UO2)2[B3O(PO4)4(HPO4)2]}·H2O		P1					[2]
	Ag2−x(NH4)3{(UO2)2[B2P5−yAsyO20−x(OH)x]}		Pcmn					[2]
	Cs3(UO2)3[B(PO4)4]∙(H2O)0.5		P41212	a=12.2376, c=33.9468, Z=4	5083.8		yellow; microporous	[59]