# 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. 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.
Different structural anions include hexaselenohypodiphosphate [P$_2$Se$_6$]$^{4−}$ and [P$_6$Se$_{12}$]$^{4−}$ with decalin structure and [P$_4$Se$_2$]$^{2−}$ with dicyclobutane structure.
Selenophosphates are coloured, often orange. They are semiconductors.
The first selenodiphosphate was discovered in 1973 by H. Hahn.
Selenophosphate compounds may have some or all of the selenium replaced by sulfur.

## 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

## List

| formula | name | mw | crystal system | space group | unit cell Å | volume | density | comments | references |
| [(py$_2$Li)]$_4$[P$_2$Se$_6$]·2py | | | | | | | | water stable | |
| (NH$_4$)$_4$(P$_2$Se$_6$)(H$_2$O)$_2$ | | | 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 | | |
| [pyH]$_4$[P$_2$Se$_6$]·H$_2$O | | | | | | | | water stable | |
| (NBu$_4$)$_2$P$_2$Se$_8$ | bis(Tetrabutylammonium) 3,6-diselenoxo-1,2,4,5-tetraselena-3,6-diphosphacyclohexane 3,6-diselenide acetonitrile solvate | | monoclinic | P2$_1$/c | a 9.6284 b 16.9553 c 16.0899 β 96.875° | | | chair config | |
| (NBu$_4$)$_3$P$_9$Se$_{14}$ | | | | | | | | orange-red | |
| | bis(1-Butyl-3-methylimidazolium) 3,6-diselenoxo-1,2,4,5-tetraselena-3,6-diphosphacyclohexane 3,6-diselenide | | monoclinic | P2$_1$/n | a =7.6642 b =10.9948 c =17.0380 β =91.211° | | | chair config | |
| | 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 | |
| | 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 | |
| Na$_2$P$_4$Se$_2$ | | | | | | | | red-brown; P$_4$ bicyclo structure | |
| Na$_3$PSe$_4$ | | | cubic | I43m | a=7.3094 Z=2 | | 3.53 | Na ion conductor 1 mS cm$^{−1}$ | |
| Na$_4$P$_2$Se$_6$ | | | orthorhombic | Cmca | a = 11.836 b = 13.311 c = 8.061 Z = 4 | 1270.0 | 3.283 | | |
| Na$_4$(P$_2$Se$_6$)(H$_2$O)$_6$ | | | monoclinic | P2$_1$/c | a 26.0636 b 7.2350 c 20.7197 β 113.387° Z=8 | 3586.13 | 2.726 | | |
| Mg$_2$P$_2$Se$_6$ | | | | R3 | a = 6.404 c = 20.194 Z=3 | | | | |
| KPSe$_6$ | | | orthorhombic | Pca2$_1$ | 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 | |
| K$_4$Sc$_2$(PSe$_4$)$_2$(P$_2$Se$_6$) | | | monoclinic | C2/c | a=22.668Å b=6.8147Å c=19.828 β=113.91° | | | | |
| K$_2$P$_2$Se$_6$ | | | trigonal | P3$_1$21 | a = 7.2728, c = 18.872 Z = 3 | | | at 298 K; SHG 50× AgGaSe$_2$ | |
| K$_2$P$_2$Se$_6$ | | | trigonal | P3$_1$21 | a = 14.4916 c = 18.7999 Z = 12 | | | at 173 K | |
| K$_3$PSe$_4$·2Se$_6$ | | | cubic | Fd3 | a = 16.415 | | | at 193 K | |
| K$_4$(P$_2$Se$_6$)(H$_2$O)$_4$ | | | orthorhombic | Cmca | a =11.921 b =12.46 c =11.752 Z=4 | 1745.6 | 2.908 | | |
| K$_6$P$_8$Se$_{18}$ | | 1903.66 | monoclinic | P2$_1$/n | a=9.746 b=8.332 c=23.054 β=90.54° Z=2 | 1872.1 | 3.377 | orange | |
| Ca$_2$P$_2$Se$_6$ | | | monoclinic | P2$_1$/n | a = 9.664 b = 7.519 c = 6.859 β = 92.02° | | | | |
| K$_4$Sc$_2$(PSe$_4$)$_2$(P$_2$Se$_6$) | | 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 | |
| KTiPSe$_5$ | | | | | | | | | |
| K$_4$Ti$_2$(P$_2$Se$_9$)$_2$(P$_2$Se$_7$) | | | | | | | | black | |
| Cr$_2$P$_2$Se$_6$ | | | | | | | | | |
| LiCrP$_2$Se$_6$ | | | | | | | | | |
| MnPSe$_3$ | | | trigonal | R3 | | | | band gap 2.5 eV | |
| K$_2$MnP$_2$Se$_6$ | | | monoclinic | P2$_1$/n | a=6.5349 b=12.696 c=7.589 β=102.67° Z=2 | 614.3 | | | |
| FePSe$_3$ | | | | | | | | | |
| Fe$_2$P$_2$Se$_6$ | | | trigonal | R3 | | | | band gap 1.3 eV | |
| K$_2$FeP$_2$Se$_6$ | | | monoclinic | P2$_1$/n | a=6.421 b=12.720 c=7.535 β=102.58 Z=2 | 600.7 | | red | |
| CuP$_2$Se | | | | | | | | 2D semiconductor; metallises under pressure | |
| m-Cu$_4$P$_2$Se$_6$ | | | monoclinic | P2$_1$/c | a 6.370 b 11.780 c 20.013 β 90.03° | | | | |
| Cu$_3$PSe$_4$ | | | orthorhombic | Pmn2$_1$ | a=7.700 b=6.677 c=6.385 | 328.3 | | | |
| t-Cu$_4$P$_2$Se$_6$ | | | triclinic | P1 | a 7.104 b 11.889 c 12.759 α 74.35° β 79.63° γ 80.85° | | | | |
| Cu$_4$P$_3$Se$_4$ | | | triclinic | P1 | a 6.440 b 7.085 c 10.616 α 73.11° β 74.86° γ 77.00° | | | | |
| Cu$_4$P$_4$Se$_3$ | | | monoclinic | P2$_1$/c | a 16.446 b 6.515 c 17.339 β 119.08° | | | | |
| CuP$_2$Se | | | orthorhombic | Pbca | a 5.608 b 6.496 c 16.570 | | | | |
| CuAl[P$_2$Se$_6$] | | | trigonal | R3 | a = 6.2795 c = 19.9713 Z =3 | | | | |
| K$_2$Cu$_2$P$_4$Se$_{10}$ | | 1118.78 | monoclinic | P2$_1$/n | a=10.627 b=7.767 c=11.966 β=109.125° Z=2 | 933.2 | 3.981 | red | |
| K$_3$Cu$_3$P$_3$Se$_9$ | | | monoclinic | P2$_1$/c | a = 8.741 b = 10.774, c = 20.033, β = 92.96° | | | | |
| [Cu$_{12}$(P$_2$Se$_6$){Se$_2$P(OEt)$_2$}$_8$] | Et=Ethyl; diethyl diselenophosphate hexaselenodiphosphate(IV) | | | | | | | | |
| [Cu$_{12}$(P$_2$Se$_6$){Se$_2$P(OiPr)$_2$}$_8$] | iPr=isopropyl | | | | | | | | |
| CuCr[P$_2$Se$_6$] | | | 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 | |
| Zn$_2$P$_2$Se$_6$ | | | | R3 | a = 6.290 c = 19.93 Z=3 | | | | |
| K$_2$ZnP$_2$Se$_6$ | | | monoclinic | P2$_1$/c | a = 12.537 b = 7.274 c = 14.164 β = 109.63° Z = 4 | 1216 | | yellow | |
| LiGaP$_2$Se$_6$ | | | | | | | | | |
| K$_4$GeP$_4$Se$_{12}$ | | | orthorhombic | Pca2$_1$ | a=13.9465 b=7.2435 c=24.0511 | | | | |
| K$_4$Ge$_{4-x}$P$_x$Se$_{12}$ | | | monoclinic | P2$_1$/c | a = 6.7388 b = 13.489 c = 6.3904 β = 91.025° | | | | |
| K$_7$As$_3$(P$_2$Se$_6$)$_4$ | | | monoclinic | P2$_1$/c | a=25.0706 b=9.5948 c=59.6227 β=93.384° | | | melt 388 °C | |
| K$_6$As$_2$(P$_2$Se$_6$)$_3$ | | | monoclinic | P2$_1$/c | a 8.0898 b 23.3142 c 12.1919 β 124.809° | | | melt 410 °C; orange; band gap 2.2 eV | |
| RbPSe$_6$ | | | orthorhombic | Pca2$_1$ | a = 11.776 b = 6.858 c = 11.460 Z = 4 | | | NLO χ$^{(2)}$≈150 pm V$^{−1}$ | |
| Rb$_2$P$_2$Se$_6$ | | | trigonal | P3$_1$21 | a = 7.2982 c = 19.002 and Z = 3 | | | 100 K | |
| Rb$_4$P$_2$Se$_9$ | | | monoclinic | C2/c | a = 9.725 b = 10.468 c = 19.155 β = 93.627° Z = 4 | 1946.1 | 3.804 | | |
| Rb$_4$P$_6$Se$_{12}$ | | | orthorhombic | Pca2$_1$ | a =16.409 b =10.64 c =15.105 | | | bicyclic with >PP< bridge and -SePSe$_2$PSe$_2$Se- ring | |
| Rb$_{10}$P$_4$Se$_{25}$ | | | | | | | | | |
| Rb$_4$(P$_2$Se$_6$)(H$_2$O)$_4$ | | | orthorhombic | Pnnm | a 9.834 b 12.456 c 7.585 Z=2 | 929.1 | 3.395 | | |
| RbTiPSe$_5$ | | | | | | | | | |
| Rb$_4$Ti$_2$(P$_2$Se$_9$)$_2$(P$_2$Se$_7$) | | | orthorhombic | Fdd2 | a=35.55 b=37.315 c=6.574 Z=4 | 8772 | 3.956 | black | |
| Rb$_2$MnP$_2$Se$_6$ | | | | | | | | | |
| Rb$_2$ZnP$_2$Se$_6$ | | | triclinic | P1 | a = 7.494 b = 7.601 c = 12.729 α = 96.57° β = 105.52° γ = 110.54° Z = 2 | 636.6 | | | |
| Rb$_4$GeP$_4$Se$_{12}$ | | | orthorhombic | Pca2$_1$ | a=14.1881 b=7.3566 c=24.2914 | | | | |
| Rb$_6$Ge$_2$P$_2$Se$_{14}$ | | | 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 | |
| Sr$_2$P$_2$Se$_6$ | | | monoclinic | P2$_1$/n | a = 9.844 b = 7.788 c = 6.963 β = 91.50° Z=2 | | | | |
| NaYP$_2$Se$_6$ | | 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 | follow up refs |
| KYP$_2$Se$_6$ | | | orthorhombic | P2$_1$2$_1$2$_1$ | a = 6.7366 b = 7.4286 c = 21.603 Z = 4 | | | | |
| [(Cp′′$_2$Zr)$_2$(μ,η$^{1:1:1:1}$-P$_2$Se$_4$)] | Cp′′ = C$_5$H$_3$tBu$_2$ | 1269.41 | monoclinic | P2$_1$/n | a=15.2831 b=9.91947 c=18.6250 β=102.835° Z=2 | 2753 | 1.531 | dark purple | |
| KZrPSe$_6$ | | | orthorhombic | Pmc2$_1$ | a=3.7079 b=15.074 c=18.491 | | | | |
| RbZrPSe$_6$ | | | | | | | | | |
| KNb$_2$PSe$_{10}$ | | | monoclinic | Pc | a=7.2931 b=15.612 c=13.557 β=106.64° | | | resistivity 4.5 Ω·cm | |
| RbNb$_2$PSe$_{10}$ | | | monoclinic | Pc | a=7.381 b=7.8359 c=13.564 β=106.75° | | | | |
| K$_3$RuP$_5$Se$_{10}$ | | | monoclinic | P2$_1$/m | a 11.2099 b 7.2868 c 12.3474 β 93.958° | | | | |
| PdPSe | | | | | | | | semiconductor | |
| K$_2$PdP$_2$Se$_6$ | | | | | | | | | |
| Rb$_2$PdP$_2$Se$_6$ | | | | | | | | | |
| Ag$_4$P$_2$Se$_6$ | | 1013.69 | orthorhombic | P2$_1$2$_1$2$_1$ | a=6.5760 b=11.5819 c=14.137 Z=4 | 1076.8 | 5.966 | melt 642 °C; dark red | |
| AgAl[P$_2$Se$_6$] | | | monoclinic | C2/m | a=6.348 b=10.989 c=7.028 β=107.2° Z=2 | | | melt 588 °C; yellow | |
| K$_2$Ag$_2$P$_2$Se$_6$ | | | monoclinic | P2$_1$/c | a=8.528 b=11.251 c=20.975 β=93.24° Z=4 | 2009 | | orange | |
| AgCrP$_2$Se$_6$ | | | monoclinic | C2/m | a=6.305 b=10.917; c=6.991 β=107.7° Z=2 | | | melt 720 °C; dark red | |
| AgCrP$_2$Se$_6$ | | | | P3$_1$12 | a=6.3257 c=20.0198 | | | layered; antiferromagnetic <42K; band gap 1.240 eV | |
| AgGa[P$_2$Se$_6$] | | | orthorhombic | Pbca | α=12.169 b=22.484 c=7.473 Z=4 | 2044.7 | | melt 450 °C; orange | |
| AgGa[P$_2$Se$_6$] | | | trigonal | P31/c | a=6.375 c=13.320 Z=2 | 468.81 | 5.05 | dark red | |
| AgScP$_2$Se$_6$ | | 688.54 | trigonal | P31/c | a=6.463 c=13.249 Z=2 | 482.93 | 4.735 | orange or brown | |
| CdPSe$_3$ | | | | | | | | | |
| K$_2$CdP$_2$Se$_6$ | | | monoclinic | P2$_1$/n | | | | dark yellow | |
| Rb$_2$CdP$_2$Se$_6$ | | 819.05 | monoclinic | P2$_1$/n | a=6.640 b=12.729 c=7.778 β=98.24° Z=2 | 650.5 | 4.180 | dark yellow; air stable | |
| Rb$_8$Cd$_4$(Se$_2$)(PSe$_4$)$_4$ | | | | | | | | | |
| InPSe$_3$ | | | | | | | | | |
| In$_2$(P$_3$Se$_9$) | | | monoclinic | P2$_1$/n | | | | | |
| LiInP$_2$Se$_6$ | | 657.46 | trigonal | P31/c | a=6.397 c=13.350 Z=2 | 473.15 | 4.615 | band gap 2.06 eV | |
| (Ph$_4$P)[In(P$_2$Se$_6$)] | | | monoclinic | C2/c | a = 23.127 b = 6.564 c = 19.083 β = 97.42° Z = 4 | 2873 | | @23 °C yellow | |
| KInP$_2$Se$_6$ | | | monoclinic | P2$_1$/n | a=7.511 b=6.4861 c=22.789 β=98.91° Z=4 | 1096.9 | | | |
| K$_5$In$_3$(μ$^3$-Se)(P$_2$Se$_6$)$_3$ | | | triclinic | P1 | a 7.6603 b 13.1854 c 18.378 α 87.04° β 88.659° γ 82.025° | | | | |
| K$_4$In$_4$(μ-Se)$_2$(P$_2$Se$_6$)$_3$ | | | monoclinic | P2$_1$/c | a 19.707 b 7.712 c 13.229 α 90° β 106.42° | | | | |
| K$_4$In$_2$(PSe$_5$)$_2$(P$_2$Se$_6$) | | | monoclinic | Cc | a=11.1564 b=22.8771 c=12.6525 β=109.039° Z=4 | | | brick-red; air stable | |
| K$_4$In$_4$(μ-Se)(P$_2$S$_{2.36}$Se$_{3.64}$)$_3$ | | | triclinic | P1 | a 7.7709 b 13.0007 c 18.9382 α 105.382° β 92.632° γ 91.91° | | | | |
| CuInP$_2$Se$_6$ | | | 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 | |
| AgInP$_2$Se$_6$ | | | 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 | |
| SnP$_2$Se$_6$ | | | | R3 | a = 6.3213 c = 19.962 | | | band gap 1.36–1.41 eV | |
| Sn$_2$P$_2$Se$_6$ | | | | | | | | | |
| Na$_{11.1}$Sn$_{2.1}$P$_{0.9}$Se$_{12}$ | | | tetragonal | I4$_1$/acd | a=14.2446 c=28.473 Z=8 | 5777.4 | 3.403 | Na$^+$ ion conductivity 3.0 mS/cm | |
| Rb$_3$Sn(PSe$_5$)(P$_2$Se$_6$) | | | monoclinic | P2$_1$/a | a=14.013 b=7.3436 c=21.983 β=106.61° Z=4 | | | black | |
| K$_{10}$Sn$_3$(P$_2$Se$_6$)$_4$ | | | trigonal | R3 | a = 24.1184 c = 7.6482 | | | @100K; band gap 1.82 eV | |
| Rb$_4$Sn$_5$P$_4$Se$_{20}$ | | 2638.41 | trigonal | P3m1 | a=7.6163 c=18.6898 Z=1 | 938.91 | 4.64 | black | |
| Rb$_4$Sn$_2$Ag$_4$(P$_2$Se$_6$)$_2$ | | | monoclinic | P2$_1$/n | a=11.189 b=7.688 c=21.850 β=94.31° Z=2 | 1874.2 | 4.639 | black | |
| Rb$_5$[Sn(PSe$_5$)$_3$] | | | triclinic | P1 | a 11.745 b 19.23 c 7.278 α 99.97° β 107.03° γ 87.16° | | | | |
| Sb$_4$(P$_2$Se$_6$)$_3$ | | | monoclinic | P2$_1$/n | a = 20.777 b = 7.4935 c = 9.4949 β = 91.25° | | | | |
| KSbP$_2$Se$_6$ | | 696.55 | | | | | | | |
| β-KSbP$_2$Se$_6$ | | 696.55 | monoclinic | P2$_1$ | a=6.8925 b=7.8523 c=10.166 β=91.487 Z=2 | 550.4 | 4.203 | dark red | |
| AgSbP$_2$Se$_6$ | | | | | | | | hygroscopic | |
| α-CsPSe$_6$ | | | monoclinic | P2$_1$/n | a = 6.877 b = 12.713 c = 11.242 β = 92.735° Z = 4 | | | orange | |
| β-CsPSe$_6$ | | 637.64 | tetragonal | P42$_1$c | a = 12.526 c = 12.781 Z = 8 | 2005.3 | 4.224 | red orange; metastable; SHG χ$^{(2)}$ ~30 pm/V | |
| Cs$_2$P$_2$Se$_8$ | | | orthorhombic | Ccce | a = 14.982 b = 24.579 c = 13.065 | | | band gap 2.44 ± 0.2 eV; P$_2$Se$_4$ ring; third harmonic generator coefficient 2.4 ± 0.1 × 10$^5$ pm$^2$/V$^2$ | |
| Cs$_3$PSe$_4$ | | | orthorhombic | Pnma | a = 10.0146 b = 11.990 c = 9.9286 Z = 4 | 1192.2 | 4.154 | | |
| Cs$_4$P$_2$Se$_9$ | | | | | | | | | |
| Cs$_4$P$_2$Se$_{10}$ | | | triclinic | P1 | a=7.359 b=7.455 c=10.142 α=85.938°, β=88.055° γ=85.609° | | | [P$_2$Se$_{10}$]$^{4−}$ | |
| Cs$_4$[P$_6$Se$_{12}$] | | 1664.98 | monoclinic | P2$_1$/n | a =10.836 b =10.5437 c =12.273 β =98.661° | 1386.3 | 3.989 | orange; melt 697; NLO | |
| Cs$_5$[P$_5$Se$_{12}$] | | 1766.92 | tetragonal | P4 | a =13.968 c =7.546 Z=2 | 1472.2 | 3.986 | orange; NLO; band gap 2.17 eV | |
| Cs$_{10}$P$_8$Se$_{20}$ | | | orthorhombic | Pnnm | a = 26.5456 b = 8.0254 c = 11.9031 Z = 2 | 2535.8 | 4.133 | (PSe$_2$)$_3$Se rings and P$_2$Se$_6$ | |
| Cs$_4$(P$_2$Se$_6$)(H$_2$O)$_4$ | | | orthorhombic | Pnnm | a=10.0514 b=12.6867 c=7.8403 Z=2 | 999.8 | 3.775 | | |
| K$_{0.6}$Cs$_{0.4}$PSe$_6$ | | | orthorhombic | Pca2$_1$ | 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 | |
| KCsP$_2$Se$_8$ | | | orthorhombic | Ccce | a = 14.782 b = 23.954 c = 13.044 | | | band gap 2.36 ± 0.2 eV | |
| Cs$_2$MnP$_2$Se$_6$ | | | monoclinic | P2$_1$/n | 6.4761 b=13.006 c=7.974 β=93.09° Z=2 | 670.6 | | | |
| Cs$_2$FeP$_2$Se$_6$ | | | | | | | | | |
| Cs$_2$Cu$_2$P$_2$Se$_6$ | | | monoclinic | P2$_1$/c | a=9.958 b=13.067 c=10.720 β=102.46° Z=4 | 1363 | | dark green | |
| Cs$_2$ZnP$_2$Se$_6$ | | | 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 | |
| Cs$_4$GeP$_4$Se$_{12}$ | | | orthorhombic | Pca2$_1$ | a=14.3268 b=7.6202 c=24.6301 | | | | |
| Cs$_6$As$_2$(P$_2$Se$_6$)$_3$ | | | monoclinic | P2$_1$/c | a=19.5759 b=7.9206 c=13.0553 β=101.914° | | | orange band gap 2.1 eV | |
| Cs$_5$As(P$_2$Se$_6$)$_2$ | | | tetragonal | P4$_2$/m | a=13.826 c=7.5173 | | | melt 416 °C; red; band gap 2.0 eV | |
| RbCsP$_2$Se$_8$ | | | orthorhombic | Ccce | | | | band gap 2.41 ± 0.2 eV | |
| CsZrPSe$_6$ | | | | | | | | band gap 2.0 eV | |
| CsNb$_2$PSe$_{10}$ | | | monoclinic | Pc | a=14.6257 b=7.8097 c=13.5533 β=98.557° | | | | |
| Cs$_4$Pd(PSe$_4$)$_2$ | | | monoclinic | P2$_1$/c | a = 7.491 b = 13.340 c = 10.030 β = 92.21° Z = 2 | | | red | |
| Cs$_{10}$Pd(PSe$_4$)$_4$ | | | tetragonal | P42c | a = 13.949 c = 11.527 Z = 4 | | | red | |
| Cs$_2$PdP$_2$Se$_6$ | | | tetragonal | P4$_2$/mnm | a = 8.5337 c = 10.5595 Z = 4 | | | black | |
| Cs$_2$Ag$_2$P$_2$Se$_6$ | | | monoclinic | P2$_1$/n | a=6.807 b=12.517 c=8.462 β=95.75° Z=2 | 717.3 | | yellow | |
| Cs$_2$CdP$_2$Se$_6$ | | | monoclinic | P2$_1$/n | | | | yellow | |
| Cs$_5$In(P$_2$Se$_6$)$_2$ | | | tetragonal | P4$_2$/m | a = 13.886 c = 7.597 Z = 2 | 1464.9 | | @23 °C; dark orange | |
| Cs$_4$Sn(P$_2$Se$_6$)$_2$ | | 1721.73 | trigonal | R3 | a=7.808 c=37.905 Z=3 | 2001.4 | 4.285 | black | |
| α-Cs$_2$SnP$_2$Se$_6$ | | 920.2 | monoclinic | P2$_1$/c | a=10.230 b =12.990 c=10.949 β=94.529° | 1450.5 | 4.2126 | orange | |
| Cs$_2$SnP$_2$Se$_6$ | | | monoclinic | P2$_1$/c | a = 10.1160 b = 12.7867 c = 11.0828 β = 94.463° | | | @100K | |
| Cs$_4$(Sn$_3$Se$_8$)[Sn(P$_2$Se$_6$)]$_2$ | | 2828.17 | tyrigonal | P3m1 | a=7.695 c=18.797 Z=1 | 964.0 | 4.872 | black; 2D | |
| Cs$_6$[Sn$_2$Se$_4$(PSe$_5$)$_2$] | | | triclinic | P1 | a 9.899 b 12.416 c 7.497 α 91.62° β 110.19° γ 79.94° | | | | |
| CuSbP$_2$Se$_6$ | | | | C2/m | | | | | |
| AgSbP$_2$Se$_6$ | | | | C2/m | | | | | |
| Cs$_8$Sb$_4$(P$_2$Se$_6$)$_5$ | | | | | | | | | |
| Ba$_2$P$_2$Se$_6$ | | | monoclinic | P2$_1$/n | a = 10.355 b = 7.862 c = 7.046 β = 90.83° Z=2 | | | | |
| Ba$_3$(PSe$_4$)$_2$ | | | monoclinic | P2$_1$/a | a = 12.282 b = 6.906 c = 18.061 β = 90.23° Z = 4 | | | | |
| Ba$_3$PO$_4$PSe$_4$ | | | triclinic | P1 | a=6.779 b=7.108 c=12.727 α=82.45 β=78.88 γ=81.34 Z=2 | | | orange | |
| KBaPSe$_4$ | | | orthorhombic | Pnma | a=11.972 b=6.973 c=10.388 Z=4 | | | pale orange | |
| KLaP$_2$Se$_6$ | | 713.71 | monoclinic | P2$_1$/c | a=12.425 b=7.8047 c=11.9279 β=109.612° | 1089.6 | 4.351 | yellow | |
| K$_2$La(P$_2$Se$_6$)$_{1/2}$(PSe$_4$) | | | monoclinic | P2$_1$/n | a = 9.4269 b = 7.2054 c = 21.0276 β = 97.484° Z = 4 | | | | |
| K$_3$La(PSe$_4$)$_2$ | | | monoclinic | P2$_1$/c | a = 9.5782 b = 17.6623 c = 9.9869 β = 90.120° Z = 4 | | | | |
| K$_3$LaP$_2$Se$_8$ | | | | | | | | | |
| K$_4$La$_{0.67}$(PSe$_4$)$_2$ | | | orthorhombic | Ibam | a = 19.0962 b = 9.1408 c = 10.2588 Z = 4 | | | | |
| K$_6$LaP$_4$Se$_{16}$ | | | | | | | | | |
| K$_{8.5}$La$_{1+1/3}$(PSe$_4$)$_4$ | | | orthorhombic | Ccca | a = 18.2133 b = 38.0914 c = 10.2665 Z = 8 | | | | |
| Ce$_4$(P$_2$Se$_6$)$_3$ | | 722.06 | monoclinic | P2$_1$/c | a = 6.8057 b = 22.969 c = 11.7226 β = 124.096° Z = 6 | | 4.741 | orange | |
| NaCeP$_2$Se$_6$ | | | monoclinic | P2$_1$/c | a = 12.1422 b = 7.6982 c = 11.7399 β = 111.545° Z=4 | | | yellow | |
| KCeP$_2$Se$_6$ | | | monoclinic | P2$_1$/c | | | | | |
| Cu$_{0.4}$Ce$_{1.2}$P$_2$Se$_6$ | | | monoclinic | P2$_1$/c | a = 12.040 b = 7.6418 c = 11.700 β = 111.269° Z = 4 | | | yellow | |
| Rb$_2$CeP$_2$Se$_7$ | | | monoclinic | P2$_1$/n | | | | red; air sensitive | |
| Rb$_3$CeP$_2$Se$_8$ | | 1090.13 | monoclinic | P2$_1$/c | a = 9.6013 b = 18.0604 c = 10.0931 β = 90.619° Z = 4 | 1750.07 | 4.137 | orange; air sensitive | |
| Rb$_9$Ce(PSe$_4$)$_4$ | | | 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 | |
| AgCeP$_2$Se$_6$ | | | monoclinic | P2$_1$/c | a = 9.971 b = 7.482 c = 11.757 β = 145.630° Z=2 | | | orange | |
| CsCe[P$_2$Se$_6$] | | | monoclinic | P2$_1$/c | a = 12.9786 b = 7.7624 c = 11.9843 β = 106.589° Z = 4 | | | | |
| KPrP$_2$Se$_6$ | | | monoclinic | P2$_1$/c | | | | | |
| Cs$_2$PrP$_2$Se$_7$ | | | monoclinic | P2$_1$/n | a=10.2118 b=7.2423 c=20.3741 β =98.624° Z=4 | | | | |
| Eu$_2$P$_2$Se$_6$ | | | monoclinic | P2$_1$/n | a = 9.779 b = 7.793 c = 6.957 β = 91.29° Z=2 | | | | |
| LiEuPSe$_4$ | | | orthorhombic | Ama2 | a = 10.5592 b = 10.415 c = 6.4924 Z = 4 | | | red; air unstable | |
| Na$_8$Eu$_2$(Si$_2$Se$_6$)$_2$ | | | monoclinic | C2/m | a=7.090 b=12.228 c=7.950 β=107.427° Z = 1 | 657.6 | | | |
| KEuPSe$_4$ | | | monoclinic | P2$_1$/m | a = 6.8469 b = 6.9521 c = 9.0436 β = 107.677° Z = 2 | | | red; air unstable | |
| KEuPSe$_4$ | | | orthorhombic | Pnma | a = 17.516 b = 7.0126 c = 6.9015 Z = 4 | | | | |
| K$_4$Eu(PSe$_4$)$_2$ | | | orthorhombic | Ibam | a = 19.020 b = 9.131 c = 10.198 Z = 4 | | | | |
| Cs$_3$GdP$_2$Se$_8$ | | | monoclinic | P2$_1$/c | | | | | |
| NaSmP$_2$Se$_6$ | | 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 | |
| Na$_9$Sm(Ge$_2$Se$_6$)$_2$ | | | monoclinic | C2/m | a = 7.916 b = 12.244 c = 7.105 β = 106.99° Z = 1 | 658.6 | | | |
| KSmP$_2$Se$_6$ | | 725.15 | monoclinic | P2$_1$ | a=6.7888 b=7.6185 c=10.1962 β=91.508 Z=2 | 527.17 | 4.568 | red | |
| CsSmP$_2$Se$_6$ | | | orthorhombic | P2$_1$2$_1$2$_1$ | a = 6.8867 b = 7.5448 c = 22.152 Z = 4 | | | | |
| NaGdP$_2$Se$_6$ | | 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 | |
| KGdP$_2$Se$_6$ | | | monoclinic | P2$_1$ | a=6.7802 b=7.5809 c=10.1967 β=91.638 Z=2 | 523.97 | 4.640 | yellow | |
| Rb$_2$GdP$_2$Se$_7$ | | 1037.73 | monoclinic | P2$_1$/n | a = 10.137 b = 7.212 c = 20.299 β = 98.23° Z = 4 | 1468.8 | 4.692 | orange; air sensitive | |
| NaTbP$_2$Se$_6$ | | 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 | |
| KTbP$_2$Se$_6$ | | | monoclinic | P2$_1$ | a=6.7609 b=7.5570 c=10.2158 β=91.732 Z=2 | 521.71 | 4.671 | yellow | |
| KTbP$_2$Se$_6$ | | | orthorhombic | | | | | red over 9.2 GPa | |
| NaDyP$_2$Se$_6$ | | 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 | |
| CsEr[P$_2$Se$_6$] | | | monoclinic | P2$_1$/c | a = 7.5381 b = 12.8192 c = 12.7647 β = 106.898° Z = 4 | | | | |
| AgErP2Se6 | | 810.83 | trigonal | P31/c | a=6.578 c=13.410 Z=2 | 502.6 | 5.358 | dark brown | |
| AgTmP2Se6 | | 812.50 | trigonal | P31/c | a=6.567 c=13.422 Z=2 | 501.27 | 5.383 | dark brown | |
| K$_3$AuP$_2$Se$_8$ | | | monoclinic | Cc | a = 7.122 b = 12.527 c = 18.666 β = 96.06° Z = 4 | | | | |
| Rb$_3$AuP$_2$Se$_8$ | | | monoclinic | Cc | | | | | |
| Cs$_3$AuP$_2$Se$_8$ | | | monoclinic | Cc | | | | | |
| K$_2$Au$_2$P$_2$Se$_6$ | | | monoclinic | C2/m | a = 12.289 b = 7.210 c = 8.107 β = 115.13° Z = 2 | | | black | |
| Rb$_2$Au$_2$P$_2$Se$_6$ | | | monoclinic | C2/m | | | | | |
| Rb$_2$Au$_2$P$_2$Se$_6$ | | | monoclinic | P2$_1$/n | a=11.961 b=10.069 c=32.137 β=91.37° Z=12 | 3869 | 4.653 | @-120 °C black | |
| Hg$_2$P$_2$Se$_6$ | | | | | | | | | |
| K$_2$HgP$_2$Se$_6$ | | | monoclinic | P2$_1$/c | a=13.031 b=7.308 c=14.167 β=110.63° Z=4 | 1262.6 | 4.285 | dark yellow | |
| Rb$_2$HgP$_2$Se$_6$ | | | monoclinic | P2$_1$/c | | | | drak yellow | |
| Rb$_8$Hg$_4$(Se$_2$)(PSe$_4$)$_4$ | | | | P4$_2$/n | a=17.654 c=7.226 | | | | |
| Tl$_4$P$_2$Se$_6$ | | | trigonal | R3 | a=6.3808 c= 20.014 | | | melt 963 K | |
| TlInP$_2$Se$_6$ | | | triclinic | P1 | a=6.4488 b=7.5420 c=12.166 α=100.72° β=93.63° γ=113.32° | | | melt 875K | |
| TlSbP$_2$Se$_6$ | | | monoclinic | P2$_1$ | a = 6.843 b = 7.841 c = 9.985 β = 90.77° Z = 2 | | | melt 720K; band gap 1.75 eV | |
| Pb$_2$P$_2$Se$_6$ | | | 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 | |
| Na$_{1.5}$Pb$_{0.75}$PSe$_4$ | | | cubic | I43d | a=14.3479 Z=16 | | | band gap 2 eV | |
| RbPbPSe$_4$ | | | | | | | | red water stable | |
| Rb$_4$Pb(PSe$_4$)$_2$ | | | orthorhombic | Ibam | a = 19.134 b = 9.369 c = 10.488 Z = 4 | | | orange water unstable | |
| CsPbPSe$_4$ | | | orthorhombic | Pnma | a = 18.607 b = 7.096 c = 6.612 Z = 4 | | | red water stable | |
| Cs$_4$Pb(PSe$_4$)$_2$ | | | | | | | | orange water unstable | |
| Bi$_4$(P$_2$Se$_6$)$_3$ | | | monoclinic | P2$_1$/n | a = 20.869 b = 7.4745 c = 9.5923 β = 91.73° | | | | |
| β-Bi$_4$(P$_2$Se$_6$)$_3$ | | | triclinic | P1 | a = 12.2303 b = 6.7640 c = 17.866 α = 90.493° β = 94.133° γ = 91.163° | | | black | |
| KBiP$_2$Se$_6$ | | 783.78 | monoclinic | P2$_1$ | a 6.9183 b 7.663 c 10.239 β 91.508° Z=2 | 542.6 | 4.797 | | |
| CuBiP$_2$Se$_6$ | | | | R3 | a = 6.553 c = 39.76 | | | lamellar; p-type semiconductor; work function 5.26 eV | |
| AgBiP$_2$Se$_6$ | | | | R3 | a = 6.652 c = 39.61 | | | lamellar | |
| Cs$_5$BiP$_4$Se$_{12}$ | | | orthorhombic | Pmc2$_1$ | a = 7.5357 b = 13.7783 c = 28.0807 Z = 4 | | | band gap 1.85 eV; melt 590 °C | |
| α-TlBiP$_2$Se$_6$ | | | monoclinic | P2$_l$/c | a =12.539 b =7.499 c =12.248 β =113.731° | | | chains; band gap 1.23,1eV | |
| β-TlBiP$_2$Se$_6$ | | | monoclinic | P2$_l$/c | a =12.25 b =7.5518 c =22.834 β =97.65° | | | melt 544 °C; layers; band gap 1.27 eV | |
| K$_2$ThP$_3$Se$_9$ | | | triclinic | P1 | a = 10.4582 b = 16.5384 c = 10.2245 α = 107.637 β = 91.652 γ = 90.343° Z = 2 | | | | |
| β-K$_2$ThP$_3$Se$_9$ | | | monoclinic | P2$_1$/n | a = 10.2697 b = 7.7765 c = 20.472 β = 92.877° Z = 4 | | | yellow | |
| Rb$_2$ThP$_3$Se$_9$ | | | triclinic | P1 | a = 10.5369 b = 16.6914, c = 10.2864 α = 107.614° β = 92.059° γ = 90.409° Z = 2 | | | | |
| Rb$_7$Th$_2$P$_6$Se$_{21}$ | | | 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 | |
| Cs$_4$Th$_4$P$_4$Se$_{26}$ | | | orthorhombic | Pbca | a = 12.0130 b = 14.5747 c = 27.134 Z = 8 | | | orange; (P$_2$Se$_9$)$^{6-}$ anion | |
| Cs$_4$Th$_2$P$_5$Se$_{17}$ | | | monoclinic | P2$_l$/c | a = 10.238 b = 32.182 c = 10.749 β = 95.832° Z = 4 | | | | |
| K$_2$UP$_3$Se$_9$ | | | triclinic | P1 | a = 10.407( b = 16.491 c = 10.143 α= 107.51° β = 91.74° γ = 90.28° Z = 4 | | | black | |
| Rb$_4$U$_2$P$_5$Se$_{17}$ | | | triclinic | P1 | a =10.0824 b = 10.6905 c = 15.7845 α = 84.678 β = 76.125 γ = 85.874° | | | @100K | |
| Rb$_4$U$_4$P$_4$Se$_{26}$ | | 3470.84 | orthorhombic | Pbca | a=11.9779 b=14.4874 c=27.1377 Z=4 | 4709.17 | 4.895 | U$^{5+}$ | |
| Cs$_2$U$_2$(P$_2$Se$_9$)(Se$_2$)$_2$ | | | orthorhombic | Pbca | a 11.769 b 14.389 c 26.537 | | | black | |