Selenophosphate

A selenophosphate is a chemical compound containing phosphate anions substituted with selenium. Over 7000 compounds are known with a bond between selenium and phosphorus. Compared to phosphorus-sulfur compounds selenophosphates are less thermally stable, and more easily destroyed by water. However they are more stable than tellurophosphates which have an even weaker phosphorus-tellurium bond.^[1] Selenophosphates have an oxidation number for phosphorus of +5. But in many there are bonds between phosphorus atoms, reducing the oxidation state to +4, Some may be termed selenophosphites.^[2]

Different structural anions include hexaselenohypodiphosphate [P₂Se₆]⁴⁻ and [P₆Se₁₂]⁴⁻ with decalin structure and [P₄Se₂]²⁻ with dicyclobutane structure.^[1]

Selenophosphates are coloured, often orange. They are semiconductors.

The first selenodiphosphate was discovered in 1973 by H. Hahn.^[3]

Selenophosphate compounds may have some or all of the selenium replaced by sulfur.^[4]

Formation

Selenophosphates can be produced by melting phosphorus selenide with metal selenides.

Molecular biology

Selenocysteine is produced in many organisms from a selenophosphate. In humans and other eucaryotes, this is facilitated by the enzyme selenophosphate synthetase 1. Selenium is connected to phosphorus using a reaction with selenide and adenosine triphosphate^[5]

List

formula	name	mw	crystal system	space group	unit cell Å	volume	density	comments	references
[(py2Li)]4[P2Se6]·2py								water stable	[6]
(NH4)4(P2Se6)(H2O)2			triclinic	P1	a=7.3306 b=7.3761 c=9.5501 α =70.405° β =74.109° γ =60.681° Z=1	420.37	2.544		[7]
[pyH]4[P2Se6]·H2O								water stable	[6]
(NBu4)2P2Se8	bis(Tetrabutylammonium) 3,6-diselenoxo-1,2,4,5-tetraselena-3,6-diphosphacyclohexane 3,6-diselenide acetonitrile solvate		monoclinic	P21/c	a 9.6284 b 16.9553 c 16.0899 β 96.875°			chair config	[8]
(NBu4)3P9Se14								orange-red	[9]
	bis(1-Butyl-3-methylimidazolium) 3,6-diselenoxo-1,2,4,5-tetraselena-3,6-diphosphacyclohexane 3,6-diselenide		monoclinic	P21/n	a =7.6642 b =10.9948 c =17.0380 β =91.211°			chair config	[8]
	bis(tetrakis(Acetonitrile-N)-lithium) 3,6-diselenoxo-1,2,4,5-tetraselena-3,6-diphosphacyclohexane 3,6-diselenide		orthorhombic	Pbam	a 20.0535(6)Å b 12.1200(5)Å c 15.0831			cradle config	[8]
	bis((Tetrapyridine)-lithium) 3,6-diselenoxo-1,2,4,5-tetraselena-3,6-diphosphacyclohexane 3,6-diselenide		triclinic	P1	a 10.1582 b 10.7716 c 12.750 α 95.271° β 94.847° γ 114.219°			cradle config	[8]
Na2P4Se2								red-brown; P4 bicyclo structure	[10]
Na3PSe4			cubic	I43m	a=7.3094 Z=2		3.53	Na ion conductor 1 mS cm−1	[11]
Na4P2Se6			orthorhombic	Cmca	a = 11.836 b = 13.311 c = 8.061 Z = 4	1270.0	3.283		[12]
Na4(P2Se6)(H2O)6			monoclinic	P21/c	a 26.0636 b 7.2350 c 20.7197 β 113.387° Z=8	3586.13	2.726		[7]
Mg2P2Se6				R3	a = 6.404 c = 20.194 Z=3				[13]
KPSe6			orthorhombic	Pca21	a = 11.49 b = 6.791 c = 11.29 Z = 4			orange; NLO χ(2)≈142.8 pm V−1; band gap 2.1 eV	[14][15][16][17]
K4Sc2(PSe4)2(P2Se6)			monoclinic	C2/c	a=22.668Å b=6.8147Å c=19.828 β=113.91°				[18]
K2P2Se6			trigonal	P3121	a = 7.2728, c = 18.872 Z = 3			at 298 K; SHG 50× AgGaSe2	[19]
K2P2Se6			trigonal	P3121	a = 14.4916 c = 18.7999 Z = 12			at 173 K	[19]
K3PSe4·2Se6			cubic	Fd3	a = 16.415			at 193 K	[20]
K4(P2Se6)(H2O)4			orthorhombic	Cmca	a =11.921 b =12.46 c =11.752 Z=4	1745.6	2.908		[7]
K6P8Se18		1903.66	monoclinic	P21/n	a=9.746 b=8.332 c=23.054 β=90.54° Z=2	1872.1	3.377	orange	[21]
Ca2P2Se6			monoclinic	P21/n	a = 9.664 b = 7.519 c = 6.859 β = 92.02°				[22]
K4Sc2(PSe4)2(P2Se6)		737.82	monoclinic	C2/c	a=22.668 b=6.815 c=19.828 β =113.91° Z=8	2800.2	3.500	orange-yellow; turns red in air; band gap 2.25 eV	[18]
KTiPSe5									[23]
K4Ti2(P2Se9)2(P2Se7)								black	[23]
Cr2P2Se6									[24]
LiCrP2Se6									[25]
MnPSe3			trigonal	R3				band gap 2.5 eV	[26][27]
K2MnP2Se6			monoclinic	P21/n	a=6.5349 b=12.696 c=7.589 β=102.67° Z=2	614.3			[28]
FePSe3									[26]
Fe2P2Se6			trigonal	R3				band gap 1.3 eV	[13][27]
K2FeP2Se6			monoclinic	P21/n	a=6.421 b=12.720 c=7.535 β=102.58 Z=2	600.7		red	[28]
CuP2Se								2D semiconductor; metallises under pressure	[29]
m-Cu4P2Se6			monoclinic	P21/c	a 6.370 b 11.780 c 20.013 β 90.03°				[30]
Cu3PSe4			orthorhombic	Pmn21	a=7.700 b=6.677 c=6.385	328.3			[31]
t-Cu4P2Se6			triclinic	P1	a 7.104 b 11.889 c 12.759 α 74.35° β 79.63° γ 80.85°				[30]
Cu4P3Se4			triclinic	P1	a 6.440 b 7.085 c 10.616 α 73.11° β 74.86° γ 77.00°				[30]
Cu4P4Se3			monoclinic	P21/c	a 16.446 b 6.515 c 17.339 β 119.08°				[30]
CuP2Se			orthorhombic	Pbca	a 5.608 b 6.496 c 16.570				[30]
CuAl[P2Se6]			trigonal	R3	a = 6.2795 c = 19.9713 Z =3				[32]
K2Cu2P4Se10		1118.78	monoclinic	P21/n	a=10.627 b=7.767 c=11.966 β=109.125° Z=2	933.2	3.981	red	[33]
K3Cu3P3Se9			monoclinic	P21/c	a = 8.741 b = 10.774, c = 20.033, β = 92.96°				[34][35]
[Cu12(P2Se6){Se2P(OEt)2}8]	Et=Ethyl; diethyl diselenophosphate hexaselenodiphosphate(IV)								[36]
[Cu12(P2Se6){Se2P(OiPr)2}8]	iPr=isopropyl								[36]
CuCr[P2Se6]			monoclinic	C2/m	a=6.193 b=10.724 c=6.909 β=107.2° Z=2	690.2	4.9	melt 730 °C; dark red	[3]
Zn2P2Se6				R3	a = 6.290 c = 19.93 Z=3				[13]
K2ZnP2Se6			monoclinic	P21/c	a = 12.537 b = 7.274 c = 14.164 β = 109.63° Z = 4	1216		yellow	[37][38]
LiGaP2Se6									[25]
K4GeP4Se12			orthorhombic	Pca21	a=13.9465 b=7.2435 c=24.0511				[39]
K4Ge4-xPxSe12			monoclinic	P21/c	a = 6.7388 b = 13.489 c = 6.3904 β = 91.025°				[40]
K7As3(P2Se6)4			monoclinic	P21/c	a=25.0706 b=9.5948 c=59.6227 β=93.384°			melt 388 °C	[41]
K6As2(P2Se6)3			monoclinic	P21/c	a 8.0898 b 23.3142 c 12.1919 β 124.809°			melt 410 °C; orange; band gap 2.2 eV	[41]
RbPSe6			orthorhombic	Pca21	a = 11.776 b = 6.858 c = 11.460 Z = 4			NLO χ(2)≈150 pm V−1	[15][16]
Rb2P2Se6			trigonal	P3121	a = 7.2982 c = 19.002 and Z = 3			100 K	[19]
Rb4P2Se9			monoclinic	C2/c	a = 9.725 b = 10.468 c = 19.155 β = 93.627° Z = 4	1946.1	3.804		[12]
Rb4P6Se12			orthorhombic	Pca21	a =16.409 b =10.64 c =15.105			bicyclic with >PP< bridge and -SePSe2PSe2Se- ring	[42]
Rb10P4Se25									[43]
Rb4(P2Se6)(H2O)4			orthorhombic	Pnnm	a 9.834 b 12.456 c 7.585 Z=2	929.1	3.395		[7]
RbTiPSe5									[23]
Rb4Ti2(P2Se9)2(P2Se7)			orthorhombic	Fdd2	a=35.55 b=37.315 c=6.574 Z=4	8772	3.956	black	[23][44]
Rb2MnP2Se6									[28]
Rb2ZnP2Se6			triclinic	P1	a = 7.494 b = 7.601 c = 12.729 α = 96.57° β = 105.52° γ = 110.54° Z = 2	636.6			[38]
Rb4GeP4Se12			orthorhombic	Pca21	a=14.1881 b=7.3566 c=24.2914				[39]
Rb6Ge2P2Se14			triclinic	P1	a = 7.2463 b = 9.707 c = 11.987 α = 79.516° β = 89.524° γ = 68.281°			band gap 2.2 eV	[40]
Sr2P2Se6			monoclinic	P21/n	a = 9.844 b = 7.788 c = 6.963 β = 91.50° Z=2				[22]
NaYP2Se6		647.6	triclinic	P1	a=6.9456 b=7.4085 c=9.5306 α=88.819° β=87.748° γ=89.580° Z=2			yellow	[45][46] follow up refs
KYP2Se6			orthorhombic	P212121	a = 6.7366 b = 7.4286 c = 21.603 Z = 4				[45][47]
[(Cp′′2Zr)2(μ,η1:1:1:1-P2Se4)]	Cp′′ = C5H3tBu2	1269.41	monoclinic	P21/n	a=15.2831 b=9.91947 c=18.6250 β=102.835° Z=2	2753	1.531	dark purple	[48]
KZrPSe6			orthorhombic	Pmc21	a=3.7079 b=15.074 c=18.491				[49]
RbZrPSe6									[49]
KNb2PSe10			monoclinic	Pc	a=7.2931 b=15.612 c=13.557 β=106.64°			resistivity 4.5 Ω·cm	[50]
RbNb2PSe10			monoclinic	Pc	a=7.381 b=7.8359 c=13.564 β=106.75°				[50]
K3RuP5Se10			monoclinic	P21/m	a 11.2099 b 7.2868 c 12.3474 β 93.958°				[51]
PdPSe								semiconductor	[52]
K2PdP2Se6									[23]
Rb2PdP2Se6									[23]
Ag4P2Se6		1013.69	orthorhombic	P212121	a=6.5760 b=11.5819 c=14.137 Z=4	1076.8	5.966	melt 642 °C; dark red	[53]
AgAl[P2Se6]			monoclinic	C2/m	a=6.348 b=10.989 c=7.028 β=107.2° Z=2			melt 588 °C; yellow	[3]
K2Ag2P2Se6			monoclinic	P21/c	a=8.528 b=11.251 c=20.975 β=93.24° Z=4	2009		orange	[28]
AgCrP2Se6			monoclinic	C2/m	a=6.305 b=10.917; c=6.991 β=107.7° Z=2			melt 720 °C; dark red	[3]
AgCrP2Se6				P3112	a=6.3257 c=20.0198			layered; antiferromagnetic <42K; band gap 1.240 eV	[54]
AgGa[P2Se6]			orthorhombic	Pbca	α=12.169 b=22.484 c=7.473 Z=4	2044.7		melt 450 °C; orange	[3]
AgGa[P2Se6]			trigonal	P31/c	a=6.375 c=13.320 Z=2	468.81	5.05	dark red	[3]
AgScP2Se6		688.54	trigonal	P31/c	a=6.463 c=13.249 Z=2	482.93	4.735	orange or brown	[55]
CdPSe3									[26]
K2CdP2Se6			monoclinic	P21/n				dark yellow	[37]
Rb2CdP2Se6		819.05	monoclinic	P21/n	a=6.640 b=12.729 c=7.778 β=98.24° Z=2	650.5	4.180	dark yellow; air stable	[37]
Rb8Cd4(Se2)(PSe4)4									[23]
InPSe3									[26]
In2(P3Se9)			monoclinic	P21/n					[34]
LiInP2Se6		657.46	trigonal	P31/c	a=6.397 c=13.350 Z=2	473.15	4.615	band gap 2.06 eV	[56]
(Ph4P)[In(P2Se6)]			monoclinic	C2/c	a = 23.127 b = 6.564 c = 19.083 β = 97.42° Z = 4	2873		@23 °C yellow	[57]
KInP2Se6			monoclinic	P21/n	a=7.511 b=6.4861 c=22.789 β=98.91° Z=4	1096.9			[58]
K5In3(μ3-Se)(P2Se6)3			triclinic	P1	a 7.6603 b 13.1854 c 18.378 α 87.04° β 88.659° γ 82.025°				[59]
K4In4(μ-Se)2(P2Se6)3			monoclinic	P21/c	a 19.707 b 7.712 c 13.229 α 90° β 106.42°				[59]
K4In2(PSe5)2(P2Se6)			monoclinic	Cc	a=11.1564 b=22.8771 c=12.6525 β=109.039° Z=4			brick-red; air stable	[60]
K4In4(μ-Se)(P2S2.36Se3.64)3			triclinic	P1	a 7.7709 b 13.0007 c 18.9382 α 105.382° β 92.632° γ 91.91°				[59]
CuInP2Se6			trigonal	P31/c	a=6.392 c=13.338 Z=2	472.0	5.0	melt 642 °C; dark red; phase transitions at 5.4 and 14.1 GPa; metallised at 25.1 GPa	[3][61]
AgInP2Se6			trigonal	P31/c	a=6.483 c=13.330 Z=2	485.2	5.2	semiconductor; melt 673 °C; dark red; band gap 1.79 eV	[62][3]
SnP2Se6				R3	a = 6.3213 c = 19.962			band gap 1.36–1.41 eV	[63]
Sn2P2Se6									[64]
Na11.1Sn2.1P0.9Se12			tetragonal	I41/acd	a=14.2446 c=28.473 Z=8	5777.4	3.403	Na+ ion conductivity 3.0 mS/cm	[65]
Rb3Sn(PSe5)(P2Se6)			monoclinic	P21/a	a=14.013 b=7.3436 c=21.983 β=106.61° Z=4			black	[60]
K10Sn3(P2Se6)4			trigonal	R3	a = 24.1184 c = 7.6482			@100K; band gap 1.82 eV	[66]
Rb4Sn5P4Se20		2638.41	trigonal	P3m1	a=7.6163 c=18.6898 Z=1	938.91	4.64	black	[67]
Rb4Sn2Ag4(P2Se6)2			monoclinic	P21/n	a=11.189 b=7.688 c=21.850 β=94.31° Z=2	1874.2	4.639	black	[23][68]
Rb5[Sn(PSe5)3]			triclinic	P1	a 11.745 b 19.23 c 7.278 α 99.97° β 107.03° γ 87.16°				[69]
Sb4(P2Se6)3			monoclinic	P21/n	a = 20.777 b = 7.4935 c = 9.4949 β = 91.25°				[70]
KSbP2Se6		696.55							[34]
β-KSbP2Se6		696.55	monoclinic	P21	a=6.8925 b=7.8523 c=10.166 β=91.487 Z=2	550.4	4.203	dark red	[71]
AgSbP2Se6								hygroscopic	[72]
α-CsPSe6			monoclinic	P21/n	a = 6.877 b = 12.713 c = 11.242 β = 92.735° Z = 4			orange	[14][15]
β-CsPSe6		637.64	tetragonal	P421c	a = 12.526 c = 12.781 Z = 8	2005.3	4.224	red orange; metastable; SHG χ(2) ~30 pm/V	[14]
Cs2P2Se8			orthorhombic	Ccce	a = 14.982 b = 24.579 c = 13.065			band gap 2.44 ± 0.2 eV; P2Se4 ring; third harmonic generator coefficient 2.4 ± 0.1 × 105 pm2/V2	[73]
Cs3PSe4			orthorhombic	Pnma	a = 10.0146 b = 11.990 c = 9.9286 Z = 4	1192.2	4.154		[12]
Cs4P2Se9									[23]
Cs4P2Se10			triclinic	P1	a=7.359 b=7.455 c=10.142 α=85.938°, β=88.055° γ=85.609°			[P2Se10]4−	[74]
Cs4[P6Se12]		1664.98	monoclinic	P21/n	a =10.836 b =10.5437 c =12.273 β =98.661°	1386.3	3.989	orange; melt 697; NLO	[75]
Cs5[P5Se12]		1766.92	tetragonal	P4	a =13.968 c =7.546 Z=2	1472.2	3.986	orange; NLO; band gap 2.17 eV	[75][76]
Cs10P8Se20			orthorhombic	Pnnm	a = 26.5456 b = 8.0254 c = 11.9031 Z = 2	2535.8	4.133	(PSe2)3Se rings and P2Se6	[77]
Cs4(P2Se6)(H2O)4			orthorhombic	Pnnm	a=10.0514 b=12.6867 c=7.8403 Z=2	999.8	3.775		[7]
K0.6Cs0.4PSe6			orthorhombic	Pca21	a=11.830 b=6.908 c=11.516 Z=4	941.1	4.085	orange; band gap 2.1 eV; SHG χ(2) ~150 pm/V	[14]
KCsP2Se8			orthorhombic	Ccce	a = 14.782 b = 23.954 c = 13.044			band gap 2.36 ± 0.2 eV	[73]
Cs2MnP2Se6			monoclinic	P21/n	6.4761 b=13.006 c=7.974 β=93.09° Z=2	670.6			[28]
Cs2FeP2Se6									[28]
Cs2Cu2P2Se6			monoclinic	P21/c	a=9.958 b=13.067 c=10.720 β=102.46° Z=4	1363		dark green	[28]
Cs2ZnP2Se6			triclinic	P1	a = 7.6543 b = 7.7006 c = 12.737 α = 97.007° β = 104.335° γ = 109.241° Z = 2	669.5		yellow; band gap 2.67 eV	[38][76]
Cs4GeP4Se12			orthorhombic	Pca21	a=14.3268 b=7.6202 c=24.6301				[39]
Cs6As2(P2Se6)3			monoclinic	P21/c	a=19.5759 b=7.9206 c=13.0553 β=101.914°			orange band gap 2.1 eV	[41]
Cs5As(P2Se6)2			tetragonal	P42/m	a=13.826 c=7.5173			melt 416 °C; red; band gap 2.0 eV	[41]
RbCsP2Se8			orthorhombic	Ccce				band gap 2.41 ± 0.2 eV	[73]
CsZrPSe6								band gap 2.0 eV	[76][49]
CsNb2PSe10			monoclinic	Pc	a=14.6257 b=7.8097 c=13.5533 β=98.557°				[50]
Cs4Pd(PSe4)2			monoclinic	P21/c	a = 7.491 b = 13.340 c = 10.030 β = 92.21° Z = 2			red	[78]
Cs10Pd(PSe4)4			tetragonal	P42c	a = 13.949 c = 11.527 Z = 4			red	[78]
Cs2PdP2Se6			tetragonal	P42/mnm	a = 8.5337 c = 10.5595 Z = 4			black	[78]
Cs2Ag2P2Se6			monoclinic	P21/n	a=6.807 b=12.517 c=8.462 β=95.75° Z=2	717.3		yellow	[28]
Cs2CdP2Se6			monoclinic	P21/n				yellow	[37]
Cs5In(P2Se6)2			tetragonal	P42/m	a = 13.886 c = 7.597 Z = 2	1464.9		@23 °C; dark orange	[57]
Cs4Sn(P2Se6)2		1721.73	trigonal	R3	a=7.808 c=37.905 Z=3	2001.4	4.285	black	[79]
α-Cs2SnP2Se6		920.2	monoclinic	P21/c	a=10.230 b =12.990 c=10.949 β=94.529°	1450.5	4.2126	orange	[79]
Cs2SnP2Se6			monoclinic	P21/c	a = 10.1160 b = 12.7867 c = 11.0828 β = 94.463°			@100K	[66]
Cs4(Sn3Se8)[Sn(P2Se6)]2		2828.17	tyrigonal	P3m1	a=7.695 c=18.797 Z=1	964.0	4.872	black; 2D	[79]
Cs6[Sn2Se4(PSe5)2]			triclinic	P1	a 9.899 b 12.416 c 7.497 α 91.62° β 110.19° γ 79.94°				[69]
CuSbP2Se6				C2/m					[80]
AgSbP2Se6				C2/m					[80]
Cs8Sb4(P2Se6)5									[34]
Ba2P2Se6			monoclinic	P21/n	a = 10.355 b = 7.862 c = 7.046 β = 90.83° Z=2				[22]
Ba3(PSe4)2			monoclinic	P21/a	a = 12.282 b = 6.906 c = 18.061 β = 90.23° Z = 4				[81][82]
Ba3PO4PSe4			triclinic	P1	a=6.779 b=7.108 c=12.727 α=82.45 β=78.88 γ=81.34 Z=2			orange	[81]
KBaPSe4			orthorhombic	Pnma	a=11.972 b=6.973 c=10.388 Z=4			pale orange	[81]
KLaP2Se6		713.71	monoclinic	P21/c	a=12.425 b=7.8047 c=11.9279 β=109.612°	1089.6	4.351	yellow	[34]
K2La(P2Se6)1/2(PSe4)			monoclinic	P21/n	a = 9.4269 b = 7.2054 c = 21.0276 β = 97.484° Z = 4				[83]
K3La(PSe4)2			monoclinic	P21/c	a = 9.5782 b = 17.6623 c = 9.9869 β = 90.120° Z = 4				[83]
K3LaP2Se8									[84]
K4La0.67(PSe4)2			orthorhombic	Ibam	a = 19.0962 b = 9.1408 c = 10.2588 Z = 4				[83]
K6LaP4Se16
K8.5La1+1/3(PSe4)4			orthorhombic	Ccca	a = 18.2133 b = 38.0914 c = 10.2665 Z = 8				[83]
Ce4(P2Se6)3		722.06	monoclinic	P21/c	a = 6.8057 b = 22.969 c = 11.7226 β = 124.096° Z = 6		4.741	orange	[85]
NaCeP2Se6			monoclinic	P21/c	a = 12.1422 b = 7.6982 c = 11.7399 β = 111.545° Z=4			yellow	[85]
KCeP2Se6			monoclinic	P21/c					[45]
Cu0.4Ce1.2P2Se6			monoclinic	P21/c	a = 12.040 b = 7.6418 c = 11.700 β = 111.269° Z = 4			yellow	[85]
Rb2CeP2Se7			monoclinic	P21/n				red; air sensitive	[86]
Rb3CeP2Se8		1090.13	monoclinic	P21/c	a = 9.6013 b = 18.0604 c = 10.0931 β = 90.619° Z = 4	1750.07	4.137	orange; air sensitive	[86]
Rb9Ce(PSe4)4			monoclinic	C2/c	a=21.446 b=10.575 c=18.784 β =115.94° Z=4	3831	3.980	orange; air and water destroyed; soluble in 18-crown-6 + dmf; band gap 2.26 eV	[43]
AgCeP2Se6			monoclinic	P21/c	a = 9.971 b = 7.482 c = 11.757 β = 145.630° Z=2			orange	[85]
CsCe[P2Se6]			monoclinic	P21/c	a = 12.9786 b = 7.7624 c = 11.9843 β = 106.589° Z = 4				[87]
KPrP2Se6			monoclinic	P21/c					[45]
Cs2PrP2Se7			monoclinic	P21/n	a=10.2118 b=7.2423 c=20.3741 β =98.624° Z=4				[88]
Eu2P2Se6			monoclinic	P21/n	a = 9.779 b = 7.793 c = 6.957 β = 91.29° Z=2				[22]
LiEuPSe4			orthorhombic	Ama2	a = 10.5592 b = 10.415 c = 6.4924 Z = 4			red; air unstable	[89]
Na8Eu2(Si2Se6)2			monoclinic	C2/m	a=7.090 b=12.228 c=7.950 β=107.427° Z = 1	657.6			[90]
KEuPSe4			monoclinic	P21/m	a = 6.8469 b = 6.9521 c = 9.0436 β = 107.677° Z = 2			red; air unstable	[89]
KEuPSe4			orthorhombic	Pnma	a = 17.516 b = 7.0126 c = 6.9015 Z = 4				[83]
K4Eu(PSe4)2			orthorhombic	Ibam	a = 19.020 b = 9.131 c = 10.198 Z = 4				[34][91]
Cs3GdP2Se8			monoclinic	P21/c					[86]
NaSmP2Se6		709.94	triclinic	P1	a 6.8368 b 7.5312 c 9.557 α 90.799° β 91.910° γ 90.351° Z=2			red	[45]
Na9Sm(Ge2Se6)2			monoclinic	C2/m	a = 7.916 b = 12.244 c = 7.105 β = 106.99° Z = 1	658.6			[90]
KSmP2Se6		725.15	monoclinic	P21	a=6.7888 b=7.6185 c=10.1962 β=91.508 Z=2	527.17	4.568	red	[92]
CsSmP2Se6			orthorhombic	P212121	a = 6.8867 b = 7.5448 c = 22.152 Z = 4				[45][87]
NaGdP2Se6		715.94	triclinic	P1	a 6.8464 b 7.4916 c 9.5372 α 90.813° β 92.026° γ 90.241° Z=2			yellow	[45]
KGdP2Se6			monoclinic	P21	a=6.7802 b=7.5809 c=10.1967 β=91.638 Z=2	523.97	4.640	yellow	[45][92]
Rb2GdP2Se7		1037.73	monoclinic	P21/n	a = 10.137 b = 7.212 c = 20.299 β = 98.23° Z = 4	1468.8	4.692	orange; air sensitive	[86]
NaTbP2Se6		717.61	triclinic	P1	a 6.8854 b 7.4580 c 9.5196 α 89.068° β 87.899° γ 89.974° Z=2			yellow	[45]
KTbP2Se6			monoclinic	P21	a=6.7609 b=7.5570 c=10.2158 β=91.732 Z=2	521.71	4.671	yellow	[45][92]
KTbP2Se6			orthorhombic					red over 9.2 GPa	[93]
NaDyP2Se6		721.19	triclinic	P1	a 6.9114 b 7.4258 c 9.5256 α 88.914° β 87.829° γ 89.695° Z=2			yellow	[45]
CsEr[P2Se6]			monoclinic	P21/c	a = 7.5381 b = 12.8192 c = 12.7647 β = 106.898° Z = 4				[87]
AgErP2Se6		810.83	trigonal	P31/c	a=6.578 c=13.410 Z=2	502.6	5.358	dark brown	[55]
AgTmP2Se6		812.50	trigonal	P31/c	a=6.567 c=13.422 Z=2	501.27	5.383	dark brown	[55]
K3AuP2Se8			monoclinic	Cc	a = 7.122 b = 12.527 c = 18.666 β = 96.06° Z = 4				[94]
Rb3AuP2Se8			monoclinic	Cc					[94]
Cs3AuP2Se8			monoclinic	Cc					[94]
K2Au2P2Se6			monoclinic	C2/m	a = 12.289 b = 7.210 c = 8.107 β = 115.13° Z = 2			black	[94]
Rb2Au2P2Se6			monoclinic	C2/m					[94]
Rb2Au2P2Se6			monoclinic	P21/n	a=11.961 b=10.069 c=32.137 β=91.37° Z=12	3869	4.653	@-120 °C black	[95]
Hg2P2Se6									[34][96]
K2HgP2Se6			monoclinic	P21/c	a=13.031 b=7.308 c=14.167 β=110.63° Z=4	1262.6	4.285	dark yellow	[37]
Rb2HgP2Se6			monoclinic	P21/c				drak yellow	[37]
Rb8Hg4(Se2)(PSe4)4				P42/n	a=17.654 c=7.226				[23][97]
Tl4P2Se6			trigonal	R3	a=6.3808 c= 20.014			melt 963 K	[34][98]
TlInP2Se6			triclinic	P1	a=6.4488 b=7.5420 c=12.166 α=100.72° β=93.63° γ=113.32°			melt 875K	[99][98]
TlSbP2Se6			monoclinic	P21	a = 6.843 b = 7.841 c = 9.985 β = 90.77° Z = 2			melt 720K; band gap 1.75 eV	[100]
Pb2P2Se6			monoclinic	Pn	a = 9.742 b = 7.662 c = 6.898 β=91.44° Z=2	514.73	6.13	melt 812 °C;band gap 1.88 eV; photoconductor	[34][101][102]
Na1.5Pb0.75PSe4			cubic	I43d	a=14.3479 Z=16			band gap 2 eV	[103]
RbPbPSe4								red water stable	[91]
Rb4Pb(PSe4)2			orthorhombic	Ibam	a = 19.134 b = 9.369 c = 10.488 Z = 4			orange water unstable	[91]
CsPbPSe4			orthorhombic	Pnma	a = 18.607 b = 7.096 c = 6.612 Z = 4			red water stable	[91]
Cs4Pb(PSe4)2								orange water unstable	[91]
Bi4(P2Se6)3			monoclinic	P21/n	a = 20.869 b = 7.4745 c = 9.5923 β = 91.73°				[70]
β-Bi4(P2Se6)3			triclinic	P1	a = 12.2303 b = 6.7640 c = 17.866 α = 90.493° β = 94.133° γ = 91.163°			black	[104]
KBiP2Se6		783.78	monoclinic	P21	a 6.9183 b 7.663 c 10.239 β 91.508° Z=2	542.6	4.797		[34][71]
CuBiP2Se6				R3	a = 6.553 c = 39.76			lamellar; p-type semiconductor; work function 5.26 eV	[105][106]
AgBiP2Se6				R3	a = 6.652 c = 39.61			lamellar	[105]
Cs5BiP4Se12			orthorhombic	Pmc21	a = 7.5357 b = 13.7783 c = 28.0807 Z = 4			band gap 1.85 eV; melt 590 °C	[107]
α-TlBiP2Se6			monoclinic	P2l/c	a =12.539 b =7.499 c =12.248 β =113.731°			chains; band gap 1.23,1eV	[108]
β-TlBiP2Se6			monoclinic	P2l/c	a =12.25 b =7.5518 c =22.834 β =97.65°			melt 544 °C; layers; band gap 1.27 eV	[108]
K2ThP3Se9			triclinic	P1	a = 10.4582 b = 16.5384 c = 10.2245 α = 107.637 β = 91.652 γ = 90.343° Z = 2				[109]
β-K2ThP3Se9			monoclinic	P21/n	a = 10.2697 b = 7.7765 c = 20.472 β = 92.877° Z = 4			yellow	[110]
Rb2ThP3Se9			triclinic	P1	a = 10.5369 b = 16.6914, c = 10.2864 α = 107.614° β = 92.059° γ = 90.409° Z = 2				[109]
Rb7Th2P6Se21			triclinic	P1	a = 11.531 b = 12.359 c = 16.161 α = 87.289° β = 75.903° γ = 88.041° Z = 2			red; band gap 2.0 eV	[111]
Cs4Th4P4Se26			orthorhombic	Pbca	a = 12.0130 b = 14.5747 c = 27.134 Z = 8			orange; (P2Se9)6- anion	[112]
Cs4Th2P5Se17			monoclinic	P2l/c	a = 10.238 b = 32.182 c = 10.749 β = 95.832° Z = 4				[109]
K2UP3Se9			triclinic	P1	a = 10.407( b = 16.491 c = 10.143 α= 107.51° β = 91.74° γ = 90.28° Z = 4			black	[23][113]
Rb4U2P5Se17			triclinic	P1	a =10.0824 b = 10.6905 c = 15.7845 α = 84.678 β = 76.125 γ = 85.874°			@100K	[114]
Rb4U4P4Se26		3470.84	orthorhombic	Pbca	a=11.9779 b=14.4874 c=27.1377 Z=4	4709.17	4.895	U5+	[115]
Cs2U2(P2Se9)(Se2)2			orthorhombic	Pbca	a 11.769 b 14.389 c 26.537			black	[116]