Silicide carbides or carbide silicides are compounds containing anions composed of silicide (Si4−) and carbide (C4−) or clusters therof. They can be considered as mixed anion compounds or intermetallic compounds, as silicon could be considered as a semimetal.

Related compounds include the germanide carbides, phosphide silicides, boride carbides and nitride carbides. Other related compounds may contain more condensed anion combinations such as the carbidonitridosilicates with C(SiN3)4 with N bridging between two silicon atoms.

Production Silicide carbide compounds can be made by heating silicon, graphite, and metal together. It is important to exclude oxygen before and during the reaction. The flux method involves a reaction in a molten metal. Gallium is suitable, because it dissolves carbon and silicon, but does not react with them.

Properties Silicide carbides are a kind of ceramic, yet they also have metallic properties. They are not as brittle as most ceramics, but are stiffer than metals. They have high melting temperatures.

In air silicide carbide compounds are stable, and are hardly affected by water. The appearance is often metallic grey. When powdered the colour is dark grey.

When ErFe2SiC is dissolved in acid, mostly methane is produced, but the products include some hydrocarbons with two and three carbon atoms.

The lanthanide contraction is evident with the cell sizes for rare earth element silicide carbides.

List formulasystemspace groupunit cell Å, ZvolumedensitycommentrefAl4SiC4hexagonalP63mca = 3.2746 c = 21.7081 201.59band gap 2.2 eVTi3SiC2hexagonalP63/mmca = 3.064 c = 17.65 Z=2143.54.53mp 2300°CTi5Si3CxY3Si2C2orthorhombicCmmma=3.845 b=15.634 c=4.213253.3Pauli paramagnetic grey metallic air stableYB17.6Si4.6R3ma=10.0841 c=16.4714Y5Si3C1.8Y1.8C2Si8(B12)3rhombohedralRma=10.101, c=16.441, Z=31452.71.551 YCr2Si2CtetragonalP4/mmma=3.998 c=5.289 Z=1Pauli paramagnetic grey metallicYCr3Si2CYMn2SiCorthorhombicCmcmZ=4YFe2SiCorthorhombicCmcmZ=4270grey metallic air stableYRu2SiCorthorhombicCmcmZ=4Ba3Si4C2tetragonalI4/mcma = 8.7693 c = 12.3885semiconductor; contains [Si4]4− and [C2]2−La3Si2C2orthorhombicCmmma=4.039,b=16.884, and c=4.506307.3grey metallic air stableLaCr2Si2CtetragonalP4/mmma=4.037 c=5.347 Z=1La2Fe2Si2CmonoclinicC2/mZ=2Ce3Si2C2orthorhombicCmmma=3.990 b=16.592 c= 4.434293.5grey metallic air stable

?ferromagnetic (TC=10KCeCr2Si2CtetragonalP4/mmma=4.020 c=5.284 Z=1grey metallicCe2Fe2Si2CmonoclinicC2/mZ=2CeMo2Si2CCeRu2SiCorthorhombicCmcmZ=4Pr3Si2C2orthorhombicCmmma=3.967 b=16.452 c=4.399287.1grey metallic air stable

ferromagnetic TC=25KPrCr2Si2CtetragonalP4/mmma=4.022, c = 5.352 Z=186.586.00grey metallic

Si-Si pair bond 2.453 ÅPrMo2Si2CtetragonalP4/mmma=4.2139 c=5.4093 Z=196.1metallic dark greyPrRu2SiCorthorhombicCmcmZ=4Nd3Si2C2orthorhombicCmmma=3.949 b=16.303 c=4.375281.7grey metallic air stable

ferromagnetic TC=30KNdCr2Si2CtetragonalP4/mmma=4.026 c=5.336 Z=1grey metallicNdRu2SiCorthorhombicCmcmZ=4Sm3Si2C2orthorhombicCmmma=3.913 b=16.073 c=4.316271.4grey metallic air stable

antiferromagnetic TN=19KSmCr2Si2CtetragonalP4/mmma=4.011 c=5.321 Z=1grey metallicSmMn2SiCorthorhombicCmcmZ=4SmFe2SiCorthorhombicCmcmZ=4278grey metallic air stableSm2Fe2Si2CmonoclinicC2/mZ=2SmRu2SiCorthorhombicCmcmZ=4Gd3Si2C2orthorhombicCmmma=3.886 b=15.863 c=4.726grey metallic air stable

antiferromagnetic TN=50KGdCr2Si2CtetragonalP4/mmma=4.007 c=5.324 Z=1263.6grey metallicGdCr3Si2ChexagonalP6/mmmGdMn2SiCorthorhombicCmcmZ=4GdFe2SiCorthorhombicCmcmZ=4273grey metallic air stableGdRu2SiCorthorhombicCmcma = 3.830, b = 11.069, c = 7.157 Z=4303.48.745silvery air stableTb3Si2C2orthorhombicCmmma=3.854 c=15.702 c=4.236256.3grey metallic air stable

antiferromagnetic TN=28KTb1.8C2Si8(B12)3rhombohedralRma=10.1171, c=16.397, Z=31453.41.583TbCr2Si2CtetragonalP4/mmma=4.002 c=5.314 Z=1grey metallicTbCr3Si2ChexagonalP6/mmmTbMn2SiCorthorhombicCmcmZ=4TbFe2SiCorthorhombicCmcmZ=4270grey metallic air stableTbRu2SiCorthorhombicCmcmZ=4Dy3Si2C2orthorhombicCmmma=3.838 b=15.611 c=4.203251.8grey metallic air stable

antiferromagnetic TN=30KDyCr2Si2CtetragonalP4/mmma=3.999 c=5.306 Z=1grey metallicDyCr3Si2ChexagonalP6/mmmDyMn2SiCorthorhombicCmcmZ=4Dy2Fe2Si2CmonoclinicC2/mgrey metallic air stableDyFe2SiCorthorhombicCmcmZ=4269grey metallic air stableDyRu2SiCorthorhombicCmcmZ=4Ho3Si2C2orthorhombicCmmma=3.828 b=15.507 c=4.189248.7grey metallic air stable

metamagnetic TN=14KHoCr2Si2CtetragonalP4/mmma=3.996 c=5.274 Z=1grey metallicHoCr3Si2ChexagonalP6/mmmHoMn2SiCorthorhombicCmcmZ=4HoFe2SiCorthorhombicCmcmZ=4267grey metallic air stableHoRu2SiCorthorhombicCmcmZ=4Er3Si2C2orthorhombicCmmma=3.811 b=15.420 c=4.172245.2grey metallic air stable

metamagneticEr1.8C2Si8(B12)3rhombohedralRma=10.0994, c=16.354, Z=31444.61.619 ErCr3Si2ChexagonalP6/mmmErMn2SiCorthorhombicCmcmZ=4ErFe2SiCorthorhombicCmcmZ=4265grey metallic air stableErRu2SiCorthorhombicCmcmZ=4Tm3Si2C2orthorhombicCmmma=3.796, b=15.328, c=4.145grey metallic air stable

metamagneticTmCr3Si2ChexagonalP6/mmmTmMn2SiCorthorhombicCmcmZ=4TmFe2SiCorthorhombicCmcmZ=4263grey metallic air stableTm2Fe2Si2CmonoclinicC2/ma = 10.497, b = 3.882, c = 6.646, β = 128.96°antiferromagnetic at TN = 2.7 K

metallicTmRu2SiCorthorhombicCmcmZ=4LuCr3Si2ChexagonalP6/mmmLuMn2SiCorthorhombicCmcmZ=4LuFe2SiCorthorhombicCmcmZ=4261grey metallic air stableLu2Fe2Si2CmonoclinicC2/mPauli paramagnetic

metallicYRe2SiCorthorhombicCmcmZ=4superconductor Tc ≈ 5.9 KY2Re2Si2CmonoclinicC2/mZ=2La2Re2Si2CmonoclinicC2/mZ=2CeRe2SiCorthorhombicCmcmZ=4Ce2Re2Si2CmonoclinicC2/mZ=2PrRe2SiCorthorhombicCmcmZ=4NdRe2SiCorthorhombicCmcmZ=4Nd2Re2Si2CmonoclinicC2/mZ=2SmRe2SiCorthorhombicCmcmZ=4Sm2Re2Si2CmonoclinicC2/mZ=2GdRe2SiCorthorhombicCmcmZ=4Gd2Re2Si2CmonoclinicC2/mZ=2TbRe2SiCorthorhombicCmcmZ=4Tb2Re2Si2CmonoclinicC2/mZ=2DyRe2SiCorthorhombicCmcmZ=4Dy2Re2Si2CmonoclinicC2/mZ=2HoRe2SiCorthorhombicCmcmZ=4Ho2Re2Si2CmonoclinicC2/mZ=2ErRe2SiCorthorhombicCmcmZ=4Er2Re2Si2CmonoclinicC2/mZ=2TmRe2SiCorthorhombicCmcmZ=4YOs2SiCorthorhombicCmcmZ=4LaOs2SiCorthorhombicCmcmZ=4CeOs2SiCorthorhombicCmcmZ=4PrOs2SiCorthorhombicCmcma=3.9602,b=11.058,c=7.172 Z=4NdOs2SiCorthorhombicCmcmZ=4SmOs2SiCorthorhombicCmcmZ=4GdOs2SiCorthorhombicCmcmZ=4TbOs2SiCorthorhombicCmcmZ=4DyOs2SiCorthorhombicCmcmZ=4HoOs2SiCorthorhombicCmcmZ=4ErOs2SiCorthorhombicCmcmZ=4TmOs2SiCorthorhombicCmcmZ=4ThCr2Si2CtetragonalThMn2SiCorthorhombicCmcmZ=4ThFe2SiCorthorhombicCmcma = 3.8632, b = 10.806, c = 6.950 Z=42908.79grey metallic air stableTh2Fe2Si2CmonoclinicC2/mZ=2ThFe10SiC2-xtetragonala = 10.053 and c = 6.516ThMo2Si2CtetragonalP4/mmma = 4.2296 c = 5.3571 Z=195.84superconductor Tc=2.2KThRu2SiCorthorhombicCmcmZ=4ThRe2SiCorthorhombicCmcmZ=4Th2Re2Si2CmonoclinicC2/ma=11.1782, b=4.1753, c=7.0293, β=128.721° Z=2ThOs2SiCorthorhombicCmcmZ=4U3Si2C2tetrahedralI4/mmma=3.5735 c=18.882 Z=2241.110.94C-Si bond 1.93 Å Spin glass freeze at 28K

grey metallic

air stableU20Si16C3hexagonalP6/mmma= 10.377 c= 8.005 Z= 1746.511.67grey metallic air stableUCr2Si2CtetragonalP4/mmma =3.983 c =5.160 Z=181.848.32UCr3Si2ChexagonalP6/mmmUMn2SiCorthorhombicCmcmZ=4U0.92Mn3Si2ChexagonalP6/mmma = 8.9463 c = 3.9367 Z=3272.878.244metallicUFe2SiCorthorhombicCmcmZ=4268grey metallic air stableU2MoSi2CtetragonalP4/mbma = 6.67 c = 4.33 UOs2SiCorthorhombicCmcmZ=4

References