Phosphidosilicates

The phosphidosilicates or phosphosilicides are inorganic compounds containing silicon bonded to phosphorus and one or more other kinds of elements. In the phosphosilicates each silicon atom is surrounded by four phosphorus atoms in a tetrahedron. The triphosphosilicates have a SiP3 unit, that can be a planar triangle like carbonate CO3. The phosphorus atoms can be shared to form different patterns e.g. [Si2P6]10− which forms pairs, and [Si3P7]3− which contains two-dimensional double layer sheets. [SiP4]8− with isolated tetrahedra, and [SiP2]2− with a three dimensional network with shared tetrahedron corners. SiP clusters can be joined, not only by sharing a P atom, but also by way of a P-P bond. This does not happen with nitridosilicates or plain silicates.

The phosphidosilicates can be considered as a subclass of the pnictogenidosilicates, where P can be substituted by N (nitridosilicates), As, or Sb. Also Silicon can be substituted to form other series of compounds by replacement with other +4 oxidation state atoms like germanium, tin, titanium or even tantalum.

List formulanamecrystal systemspace groupunit cell ÅformMWdensitypropertiesreferencesLi2SiP2tetragonalI41/acda=12.111 Å, c=18.658 Å, Z=32 V=2732.64 SiP4 tetrahedra are linked together to form a supertetrahedron. Supertetrahedrons are linked together by corner sharing.103.912.02LiSi2P3I41/aa=18.4757  Å, c=35.0982  Å, Z=100Interpenetrating networks of bridged supertetrahedraLi3Si3P7monoclinicP21/ma = 6.3356 Å, b = 7.2198 Å, c = 10.6176 Å, β = 102.941°, Z = 2greyLi5SiP3CubicFmma=5.84 Z=1.33SiP4 tetrahedra, but some Si replace by LiLi10Si2P6P21/na = 7.2051 Å, b = 6.5808 Å, c = 11.6405 Å, β = 90.580°, Z = 4contains Si2P6 units with two Si atoms linked by two P atomsalso known by Li5SiP3Li8SiP4lithium orthophosphidosilicatecubicPa3a=11.6784 Z=8 V=1592.76207.491.73orange redLi14SiP6CubicFmma=5.9393 Z=4SiP4 tetrahedra, but some Si replace by Li1.644Na19Si13P25triclinicPa =13.3550 Å, b =15.3909 Å, c =15.4609 Å, α =118.05°, β =111.71°, γ =93.05°, Z =2T3 supertetrahedrasodium ion conductorNa23Si19P33monoclinicC2/ca =28.4985 Å, b =16.3175 Å, c = 13.8732 Å, β =102.35°, Z =4solely T3 supertetrahedrasodium ion conductorNa23Si28P45monoclinicP21/ca =19.1630 Å, b =23.4038 Å, c = 19.0220 Å, β =104.30°, Z =4T3 and T4 supertetrahedrasodium ion conductorNa23Si37P57monoclinicC2/ca =34.1017 Å, b =16.5140 Å, c = 19.5764 Å, β =111.53°, Z =4solely T4 supertetrahedrasodium ion conductorLT-NaSi2P3tetragonalI41/aa =19.5431 Å, c = 34.5317 Å, Z =100fused T4 and T5 supertetrahedrasodium ion conductorHT-NaSi2P3tetragonalI41/acda =20.8976 Å, c = 40.081 Å, Z =128solely fused T5 supertetrahedrasodium ion conductorNa2SiP2disodium diphosphidosilicateTetrahedralPccna = 12.7929 Å, b = 22.3109 Å, c = 6.0522 Å and Z = 16edge‐shared SiP4 tetrahedra with 1 width chainsdark red 0.43 eVNa5SiP3monoclinicP21/cZ=4 a= 7.352 Å, b= 7.957, Å c= 13.164 Å, α=90.757°2.06also known by Na10Si2P6 band gap 1.292 eVNa3K2SiP3trisodium dipotassium triphosphidosilicateOrthorhombicPnmaa=14.580 b=4.750 c= 13.020 V=901.7 Z=4SiP3 trianglesNa4Ca2SiP4hexagonalP63mca=913 c=617 V=151.5SiP4 tetrahedra2.128Na4Sr2SiP4hexagonalP63mca=9.283 c=7.295 V=1642.498Na4Eu2SiP4hexagonalP63mca=9.251 c=7.198 V=160.73.226MgSiP2tetragonalI2da=5.721 c=10.095orange yellow; semiconductor band gap 2.24 eV; decomposed by water or acidAlSiP3orthorhombicPmnba = 9.872, b = 5.861, c = 6.088, Z=4P-P bondsblackK2SiP2orthorhombicIbama = 12.926, b = 6.867, c= 6.107, Z=4, V=542.07one dimensional chain2.061KSi2P3monoclinicC2/ca=10.1327 Å, b=10.1382 Å, c=21.118 Å, β=96.88°, Z=8 V=2153.8Å3solely fused T3 supertetrahedra2.321dark red, band gap 1.72 eVKSi2P3tetragonalI41/acda =21.922 Å, c = 39.868 Å, Z =128solely fused T5 supertetrahedrapotassium ion conductorCa2Si2P4P41212a = 7.173, c = 26.295band gap 0.984 eVCa3Si2P4monoclinica = 7.073 Å, b = 17.210 Å, c = 6.918 Å, β = 111.791°band gap 0.826 eVCa3Si8P14monoclinicP21/ca = 12.138 Å, b = 13.476 Å, c = 6.2176 Å, β = 90.934°band gap 0.829 eVCa4SiP4cubica=11.875 V=16752.48Ca2Li4SiP4monoclinicP21/ma=6.7229 b=8.2100 c=7.1669 β=90.064 Z=2395.582.182MnSiP2tetrahedralI 4 2 da 5.5823 c 10.230metallic; SHG 32.8 pm/VFe5SiPa=6.766 c=12.456 V=493.8 Z=66.83CoSi3P3monoclinicP21(pseudo orthrhombic) a = 5.899, b = 5.703, c = 12.736, β = 90.00° Z=4resistivity 0.62 Ohm cm band gap 0.12 eVNiSi3P4tetragonalI2ma = 5.1598 c =10.350 Z = 23.22 NiSi2P3Imm2a = 3.505, b = 11.071, c = 5.307, Z = 2FeSi4P4a = 4.876, b = 5.545, c = 6.064, α = 85.33°, β = 68.40°, γ = 70.43° Z=4 P and Si random3.38resistivity 0.3 Ohm cm band gap 0.15, can take in Li or NaCu4SiP8I41/aa = 12.186, c = 5.732, Z = 8P-P bondsZnSiP2TetragonalI2da = 5.399 Å c = 10.435 Å Z=4 V=304.173 Å3chalcopyrite structure SiP4 and Zn4 tetrahedra154.9363.3 (measured)dark red clear; red luminescent; semiconductor; band gap 2.01 eVZnSiP2Cubicover 27 GPa Superconductor Tc = 8.2KSr2SiP4band gap 1.41 eVSr4SiP4cubica=12.426 V=19193.48SrSi7P10triclinicP1a =6.1521 Å, b =8.0420 Å, c =8.1374 Å, α =106.854°, β =99.020°, γ =105.190°, Z =1tetrahedral network derived from T2 supertetrahedraband gap 1.1 eVLi4Sr2SiP4monoclinicP21/ma=7.2919 b=8.3679 c=6.9965 β=90.061 Z=2isolated SiP4426.912.76dark red; air sensitive; indirect band gap 2.23 eVMg2Sr3Si20P30 hexagonalP63a = 15.7767 c = 11.7407 MgSr3Si3P7P31ma = 18.7339 c = 6.1393 RhSi3P3monoclinicC2a=5.525, b=7.210, c=5.522 β=118.31°, Z=2 P and Si random4.005blackRuSi4P4triclinicP1a = 4.936, b = 5.634, c = 6.162, α = 85.51°, β = 68.26°, γ = 70.69° Z=1 V=1503.74metallicRuSi4P4triclinicP1a=4.9362 b=5.6326 c=6.1649 α=85.5073° β=68.2559° γ=70.6990°3.732dark red;band gap 1.9 eVAgSiP2TetragonalI2d6.5275, c = 8.550, Z = 4; V = 364.3 SiP4 corner sharing305.775.58shiny blackMg2In3Si2P7monoclinicP21a 6.9375 b 6.5646 c 14.469 β 103.87° Z=2639.73.458SHG 7.1 × AgGaS2; band gap 2.21Sn4.2Si9P16rhombohedralR3a = 9.504 Å, α = 111.00°, and Z = 1band gap 0.2CdSiP2tetragonalI2da = 5.680 c = 10.431 Å Z=4 V=336.494 Å3chalcopyrite structure202.4343.995carmine colour; red luminescentCs2SiP2Dicesium catena-diphosphidosilicateOrthorhombic IbamCs5SiP3Pentacesium triphosphidosilicateOrthorhombicPnmaa=6.064, b=14.336, c=15.722SiP3 planar trianglesdark metallic, air sensitiveBaSi7P10triclinicP1a =6.1537 Å, b =8.0423 Å, c =8.1401 Å, α =106.863°, β =99.050°, γ =105.188°, Z =1tetrahedral network derived from T2 supertetrahedraBa2SiP4TetragonalI2da = 9.90.57 Å, c = 7.31.80 Å; Z = 4 V=718.06 Åcontains P-P bonds426.65band gap 1.45 eVBa2SiP4OrthorhombicPnmaa=12.3710 b=4.6296 c=7.9783 Z= 8 V=1443.9chains of Si-P-Si426.653.925black band gap 1.7 eVBa2Si3P6band gap 1.88Ba3Si4P6monoclinicP21/ma=1153.7 Å, b=728.1 Å, c=752.7 Å, β = 99.41° V=623.76 Z=2Zintl compound P-P and Si-Si bonds3.78black metallicBa4SiP4cubica=13.023 V=22194.22Ba4Li16Si3P12monoclinicP21/ca=16.6933 b=11.5994 c=29.5092 β=115.277 Z=8[SiP4]8−, [SiP3]5− and P3− 5166.852.870BaCuSi2P3monoclinica=4.5659 b=10.1726 c=6.8236 β = 109.311 V=299.10layeredBaIn2Si7P12trigonalR3a=13.2045 c=8.9694 Z=31354.43.440black; NLO 6 × AGSLaSiP3monoclinica = 5.972, b = 25.255, c = 4.168, β= 135.71°, Z = 4two dimensional network of boat-shaped six-membered rings of Si-P-Si-P-Si-PLaSi2P6Cmc21a=10.129 b=28.17 c=10.374 Z=16P-P bonds380.93.42greyLa2Mg3SiP6orthorhombicPnmaa=11.421 b=8.213 c=10.677 Z=4CeSiP3orthorhombicPn21aa = 5.861, b= 5.712, c= 25.295 V=846.7 Å3, Z=8P-P bonds261.134.095CeSi2P6Cmc21a= 10.118 b= 28.03 c= 10.311 Z= 16, V=2.924P-P bonds382.13.47greyCe2Mg3SiP6orthorhombicPnmaa=11.356 b=8.188 c=10.564 Z=4PrSi2P6Cmc21a= 10.085 b= 27.95 c= 10.267 Z= 16, V=2.895 nm3P-P bondsgreyNdSi2P6Cmc21a= 10.031,b= 27.81,c= 10.245,Z= 16, V=2.857P-P bondsgreyEu2Li4SiP4monoclinicP21/ma=6.9016 b=8.3330 c=7.2403 β=90.119 Z=2416.393.857ReSi4P4OsSi4P4triclinicP1a = 4.948, b = 5.620, c = 6.175, α = 85.65, β = 68.36, γ = 70.89, Z=4 V=150.64.72metallicIrSi3P3monoclinicC2a=6.577, b=7.229, c=5.484 β=117.91°, Z=2 blackIrSi3P3monoclinicCma=6.5895 b=7.2470 c=5.4916 β=117.892dark red;band gap 1.8 eVPtSi2P2monoclinicP21a=6.025 Å, b=9.468 Å, c=11.913 Å, β=102.91°,Z=8, V=552.26.327high resistance metallic, shiny black, air sensitivePtSi3P2triclinicP1a=4.840 Å,b=5.482 Å,c=8.052 Å, α=91.57°, β=93.52°, γ=108.14°, Z=2 V=202.35.656shiny blackAuSiPrhombohedralR3ma=3.459, c = 17.200, Z = 3; V = 178.19256.037.16shiny blackTh2SiP5triclinica=4.04.3 Å, b=4.04.5 Å, c = 10.279 pm, α = 90.09°, β = 90.09° and γ = 89.50°, Z = 1chains of corner linked SiP4 tetrahedra, and square net of P

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