Nitridosilicate

Source: Wikipedia, the free encyclopedia.

The nitridosilicates are chemical compounds that have anions with

tetrahedral arrangement.[1]

Related compounds include pnictogenidosilicates :phosphidosilicates, arsenidosilicates and antimonosilicates; pnictogenidogernamates: phosphidogermanates. By replacing silicon, there are also nitridogermanates, nitridostannates, nitridotantalates and nitridotitanates.

Use

Nitridosilicates are used as host substances for

LED phosphors. Examples include CASN (calcium aluminium silicide nitride) (CaAlSiN3), SCASN (SrCaAlSiN3) and SCSN (SrCaSiN3). These fluoresce red.[2]

Production

Nitridosilicates can be made in a

solid state reaction by heating silicon nitride with metallic nitrides in a nitrogen atmosphere at over 1300°C. If the mixtures are exposed to oxygen or air, then oxides or oxynitridosilicates are produced instead. Instead of metal nitrides, ammine complexes, amides or imides can be used instead. In place of the highly stable silicon nitride, silicon diimide can be used.[3] Carbothermal reduction involves using a metal oxide or carbonate heated with carbon in a nitrogen atmosphere.[4]

Properties

The ratio of silicon to nitrogen varies from 1:4 to 7:10 (0.25 to 0.7) with increased condensation, and fewer sites for metals with high silicon content. At a ratio of 3:4 (0.75) there is no longer capacity for metal, as that is silicon nitride.[5] The more condensed substances, with lower nitrogen content, have greater number of silicon atoms surrounding the nitrogen. This coordination number can vary from one to four, with the most common being three. The silicon atom always is coordinated by four nitrogen atoms. In the silicates, silicon is surrounded by four oxygen atoms, but each oxygen is only connected to one or two silicon atoms, and only very rarely three. So nitridosilicates can form more diverse structures than the silicates.[6]

Nitridosilicates with higher proportion of silicon (more condensed) are more resistant to attack by water and oxygen, and so can be exposed to the atmosphere without decomposition.[6] These condensed nitridosilicates are mechanically strong, and resistant to heat, acids and alkalis.[1]

SiN4 tetrahedra can be connected to each other via vertices or edges. This differs from SiO4 which only connects via vertices.[1]

Use

Nitridosilicates have been used to make

cutting tools and phosphors.[4]

Nitridosilicates

name formula formula

weight

crystal

system

space

group

unit cell volume density comments ref
LiSi2N3 [5]
Li2SiN2 [7]
Li5SiN3 [7]
Li8SiN4 [8]
Li18Si3N10 [7]
Li21Si3N11 I4 a=9.4584 c=9.5194 antifluorite structure [7]
BeSiN2 [9]
MgSiN2 [5]
NaSi2N3 [9]
Ca2Si5N8 332.64 monoclinic Cc a = 14.3280 b = 5.61165 c = 9.69406 β = 112.1484 Z=4 721.92 3.06 Eu orange fluorescence [5][10][4]
CaSiN2 [5]
Ca3SiN3H monoclinic C2/c a = 5.236 b = 10.461 c = 16.389 β = 91.182° Z = 8 semiconductor: band gap 3.1 eV [11]
Ca4SiN4 [5]
Ca5Si2N6 [5]
Ca12Si4[SiN4] triclinic P1 a 9.0103 b 9.0218 c 13.8252 α 71.053° β 82.738° γ 69.763° black [12]
Ca16Si17N34 [5]
CaMg3SiN4 I41/a [13]
Ca5[Si2Al2N8] orthorhombic Pbcn a = 9.255 b = 6.140 c = 15.578 [14]
LiCa3Si2N5 monoclinic C2/c a = 5.145 b = 20.380 c = 10.357 β = 91.24° [15]
Li4Ca3Si2N6 288.24 monoclinic C2/m a=5.787 b=9.705 c=5.977 β=90.45 335.7 2.852 [5][16]
Li2CaSi2N4 [5]
Li2Ca2Mg2Si2N6 [5]
Li2Ca3MgSi2N6 [5]
CaMg3SiN4 I41/a a = 11.424 c = 13.445 Z=16 [9]
CaAlSiN3 orthorhombic Cmc21 Eu yellow fluorescence [17]
CaAlSi4N7 orthorhombic Pna21 a = 11.6819, b = 21.0193, c = 4.9177 Å [18]
Ca4AlSiN5 orthorhombic Pna21 a 11.2058 b 9.0512 c 6.0203 faint red [12]
Ca5Al2Si2N8 orthorhombic Pbca a= 9.255 b = 6.140 c = 15.578 Z=4 885.2 3.171 yellow [9][19]
CaScSi4N7 [5]
Manganese silicide dinitride MnSiN2 orthorhombic Pna21 a = 5.271, b = 6.521, and c = 5.0706 V=174.26 intense red [8]
Fe2Si5N8 364.23 monoclinic Cc a= 14.0408 b = 5.32635 c = 9.5913 β = 110.728 Z=4 decompose 1370K; brown [10]
ZnSiN2 [9]
SrSiN2 [5]
Sr2Si5N8 orthorhombic Pmn21 a = 5.71006 b = 6.81914 c = 9.33599 Z=2 363.52 3.908 Eu red fluorescence [5][4][20]
SrSi6N8 [5]
SrSi7N10 [18]
Sr5Si7P2N16 920.83 Pnma a=5.6748 b=28.0367 c=9.5280 Z=4 1522.1 4.018 [21]
SrAlSi4N7 orthorhombic Pna21 a = 11.742 b = 21.391 c = 4.966 Z = 8 1247.2 [22]
Li2SrSi2N4 cubic a=10.69 Z=12 1220 [5][23]
Li4Sr3Si2N6 monoclinic C2/m a = 6.127, b = 9.687, c = 6.220, β = 90.24° Z=2 369.1 3.876 [16]
SrBeSi2N4 p62c a=4.86082 c=9.42264 Z=2 [24]
SrMg3SiN4 I41/a a = 11.495 c = 13.512 Z=16 [9][13]
Sr8Mg7Si9N22 Cm a 15.280 b 7.4691 c 10.936 β 110.462° [25]
SrAlSiN3 Cmc21 [17]
SrAlSi4N7 Pna21 [18]
SrScSi4N7 [5]
YScSi4N6C hexagonal P63mc a=5.9109 c=9.677 [26]
CaYSi4N7 [5]
SrYSi4N7 [5]
Ca8In2SiN4 orthorhombic Ibam a = 12.904 b = 9.688 c = 10.899 Z = 4 metallic [11]
BaSiN2 [5]
Ba5Si2N6 [9]
Ba2Si5N8 orthorhombic Pmn21 Eu red fluorescence [5][4]
BaSi6N8 Imm2 a = 7.9316, b = 9.3437, c = 4.8357, Z = 2 358.38 [5][27]
BaSi7N10 monoclinic a = 6.8729, b = 6.7129, c = 9.6328, β = 106.269, Z = 2 most condensed [5][28]
Ba6Si6N10O2(CN2) P6 a = 16.255, c = 5.469, Z = 3 yellow, grown in liquid sodium [29]
BaMg3SiN4 P1 a = 3.451 b = 6.069 c = 6.101 α = 85.200 β = 73.697 γ = 73.566° Z=1 [30]
Ba2AlSi5N9 triclinic P1 a = 9.860 b = 10.320 c = 10.346 α = 90.37° β = 118.43° γ = 103.69° Z = 4 [31]
Ba5Si11Al7N25 Pnnm a = 9.5923, b = 21.3991, c = 5.8889 Å Z = 2 with Eu yellow emission [32]
BaSi4Al3N9 P21/C a = 5.8465, b = 26.726, c = 5.8386 Å, β = 118.897° and Z = 4 with Eu blue emission [32]
BaScSi4N7 [5]
BaYSi4N7 [5]
LaSi3N5 [5]
La3Si6N11 [5]
La5Si3N9 [9]
La7Si6N15 [9]
Li5La5Si4N12 tetragonal P4b2 a = 11.043 c = 5.573 Z = 2 [33]
calcium lanthanum nitridosilicate CaLaSiN3 Ca can be substituted by Yb or Eu [34]
CaLaSi4N7 [5]
CeSi3N5 [9]
Ce3Si6N11 [9]
Ce3Si5N9 [9]
Ce7Si6N15 triclinic [9]
Ce7Si6N15 trigonal [9]
Li5Ce5Si4N12 tetragonal P4b2 a = 10.978 c = 5.514 Z = 2 [33]
Pr3Si6N11 [9]
Pr5Si3N9 [9]
Pr7Si6N15 [9]
Ba2Nd7Si11N23 dark blue [35]
Sm3Si6M11 [9]
Ca3Sm3[Si9N17] cubic P4_3m a=7.3950; Z=1 404.4 [36]
Eu2SiN3 Cmca a = 5.42, b = 10.610, c = 11.629, Z = 8 [9][37]
dieuropium penta siliconoctanitride Eu2Si5N8 orthorhombic Pnm21 a=5.7094 b=6.8207 c=9.3291 Z=2 363.29 5.087 red [9][38]
EuMg3SiN4 I41/a a = 11.511 c = 13.552 Z=16 [13]
Ca3Yb3[Si9N17] cubic P4_3m a=730.20 Z=1 389.3 [36]
BaYbSi4N7 includes NSi4 clusters [9][39]
europium ytterbium tetrasiliconheptanitride EuYbSi4N7 hexagonal P63mc a=5.9822 c=9.7455 302.03 5.887 brown [9][38]
SrYbSi4N7 [9]
EuYbSi4N7 [9]
CaLuSi4N7 [5]
SrLuSi4N7 [5]
BaLuSi4N7 [5]
Pb2Si5N8 666.90 orthorhombic Pmn21 a = 5.774 b = 6.837 c = 9.350 269.11 6.001 Pb-Pb dumbells [20]

References

  1. ^ a b c Philipp Bielec (27 July 2019). The Ion Exchange Approach - Expanding Elemental Variety in Nitridosilicate Chemistry (PDF) (Thesis).
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