TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The metal complex does not have charge, i.e. electrically neutral.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The electronic device comprises anode, cathode and at least one layer. The layer contains at least one organic or organometallic compound. The organic electroluminescent devices contains cathode, anode and at least one emitting layer and optionally at least one hole injection layer, hole transport layer, hole blocking layer, electron transport layer, electron injection layer, exciton blocking layer, charge generation layer and/or organic or inorganic p/n- junctions. The metal complex (I) is used in combination with at least one matrix materials, which is N,N-biscarbazolylbiphenyl, carbazole derivative, azacarbazole, ketone, phosphine oxide, sulfoxide, sulfone, oligophenyl, aromatic amine, bipolar matrix material, silane, 9,9-diarylfluorene derivative, azaborole or boron. Preferred Definitions:    M = penta-coordinated or hexa-coordinated transition metal, which is Mo, W, Re, Ru, Os, Rh, Ir, Pt or Au (all preferred), Cr, Ni, Cu or Ag;    (C?=N-R)x = 1,3-bis(2-isocyanophenyl)propane, 1,3-bis(2-isocyanophenyl)cyclohexane, 1,4-bis(3-isocyanophenyl)butane, 1,2-bis(3-isocyanobenzyl)cyclohexane, 1,2-bis(3-isocyanobenzyl)benzene, (Z)-1,4-bis(3-isocyanophenyl)but-2-ene, 2,2''-Diisocyano-(1,1';4',1'')terphenyl, 1,2,3-tris(2-isocyanobenzyl)cyclopropane, 2,2'-(3-(2-isocyanophenethyl)pentane-1,5-diyl)bis(isocyanobenzene), 1,3,5-tris(2-isocyanophenyl)benzene or 1,3,5-tris(2-isocyanophenyl)cyclohexane (all substituted by R1); either    L = carbon monoxide, amines, phosphines, phosphites, arsines, stibine, nitrogen-containing heterocycles, carbenes, hydride, deuteride, F, Cl, Br and I, alkylacetylide, arylacetylide, cyanide, cyanate, isocyanate, thiocyanate, isothiocyanate, aliphatic or aromatic alcoholates, aliphatic or aromatic thio-alcoholate, amides, carboxylates, aryl groups, anionic, nitrogen-containing heterocycle, O2-, S2- or carbide (which lead to coordination of the form R-C?= M), or nitrene (which leads to a coordination of the form R-N = M), or N3-, diamines, imines, diminuendo, heterocycles containing two nitrogen atoms, diphosphines, 1,3-diketonates derived from 1,3-diketones, 3-ketonates derived from 3-keto esters, carboxylates derived from amino carboxylic acids, salicyliminate derived from salicylimine, dialcoholate derived from diols, dithiolate derived from dithiol, bristle nitrogenous heterocycles, eta 5-cyclopentadienyl, eta 5-pentamethylcyclopentadienyl, eta 6-benzene or eta 7-cycloheptatrienyl, which is optionally substituted by R1, or a monoanionic bidentate ligand, which with the metal shows a cyclometalated five-membered ring or six-membered ring with at least one metal-carbon bond, preferably a combination of the two groups e.g. cyclometalated group of formulae (A) to (E), where one group binds over a neutral nitrogen atom or a carbene atom and the other group binds with a negatively charged carbon atom or a negatively charged nitrogen atom, or 1,3,5-cis-cyclohexane derivative of formula (F), a 1,1,1-tri(methylene)methane derivative of formula (G) and a 1,1,1-trisubstituted methane of formula (H) and (I); or    R+L = mono- or polycyclic, aliphatic, aromatic and/or benzoannelated structure, so the ligand exhibits multidentate and/or polypodal ligand character;    X = CR1 or N with the proviso that maximum three X represents N; and    A = O-, S-, COO-, P(R1)2 or N(R1)2.    SPECIFIC COMPOUNDS - Use of 102 compounds (I) is disclosed, e.g. hexa(phenylisocyano)molybdenum of formula (Ia); hexa((1,6-diisopropylphenyl)isocyano)molybdenum; tricarbonyl(tris(phenylisocyano))molybdenum; hexa((2,6-dimethylphenyl)isocyano)tungsten; and tetra(phenylisocyano)-dichlororuthenium    EXAMPLE - Hexakis(phenyl-isonitrile) molybdenum(0), hexakis(phenyl-isonitrile)tungsten(0) and hexakis(2,4,6-tri-tert-butylphenyl-isonitrile)tungsten(0) were prepared according to Albers et al., J. Chem. Edu. 1986, 63(5), 444, Coville et al., Inorg. Chim. Acta 1982, 65, L7-L8, bzw. Yamamoto et al., J. Organomet. Chem. 1985, 282, 191. The compounds were repeatedly recrystallized by toluene/ethanol (1:2-1:1). The obtained metal complex had a purity of greater than 99.8%.