Method for producing metal carbodiimides

Abstract

The present invention relates to a process for producing metal carbodiimides, characterized in that the metal carbodiimides satisfy the following chemical formula (1): A x B y (NCN)3 (1), where - A is a metal cation with oxidation state x, - B is a metal cation with oxidation state y, where - x and y are chosen such that A x B y (NCN)3 results in an electrically neutral compound, the procedure comprises the following steps: a) Providing a mixture of AHal m , BHal n and M p NCN, wherein M is selected from zinc, lithium and sodium, wherein Hal is a halogen selected from fluorine, chlorine or bromine and wherein m, n and p are selected such that AHal m , BHal n and M p NCN each result in electrically neutral compounds; and b) Treating the mixture at a temperature in the range of at least 500 °C.

Description

[0001] The present invention relates to a method for producing metal carbodiimides. The present invention further relates to metal carbodiimides produced in particular by such a method, and to the application of the metal carbodiimides in the energy sector, in semiconductor technology, and in information technology.

[0002] Although the broad field of oxide chemistry with O 2- Anions are often used as a starting point for the synthesis of new carbodiimide / cyanamide compounds with NCN. 2- Using complex anions poses problems due to their low thermal stability.

[0003] Due to their metastability and higher covalency compared to analogous oxides, dinitridocarbonates in their two different forms, either as carbodiimides or as cyanamides, often exhibit unique properties compared to their oxide analogs and are therefore promising for a variety of practical applications. Solid-state metal carbodiimides, in particular, have been used as negative electrode materials in alkali metal ion batteries, as well as in photovoltaic devices, fluorescent light sources, and light-emitting diodes, so their higher covalency is also advantageous in these applications.

[0004] Bhalla, A., Guo, R. & Roy, R. The perovskite structure - a review of its role in ceramic science and technology. Mat Res Innovat 4, 3-26 (2000) describes various aspects of the perovskite structure.

[0005] Shellaiah, M.: Review on Sensing Applications of Perovskite Nanomaterials Chemosensors; 2020, 8, 55 describes the application of materials with a perovskite structure in sensor applications.

[0006] Launay, M.: A Theoretical Study on the Structures and Energetics of Hypothetical TiM(NCN)3 Compounds of the 3d Transition Metals J Comput Chem 26: 1180-1188, 2005, describes a theoretical study on the hypothetical compound TiM(NCN)3.

[0007] CN 115441046 describes the structure Li₂M(CN₂)₃, where M stands for Ti, Sn, Ge, Mn, Si, and Zr. Furthermore, the application of compounds of this structure as ionic conductors in lithium batteries is described.

[0008] EP 3 104 437 A1 concerns the use of a metal carbodiimide or a metal cyanamide as an active material for a negative electrode. Furthermore, a corresponding electrode, the manufacturing process for a battery, and a method for producing a composite material are described.

[0009] However, the current state of the art still offers potential for improvement.

[0010] It is therefore the object of the present invention to at least partially improve upon at least one disadvantage of the prior art. In particular, it is the object of the present invention to provide a solution by which novel carbodiimide compounds with advantageous properties and / or applications can be produced.

[0011] The problem is solved according to the invention by a method having the features of claim 1. The problem is further solved by metal carbodiimides having the features of claim 7 and by use having the features of claim 13. Preferred embodiments of the invention are disclosed in the dependent claims, in the description and in the figures, wherein further features described or shown in the dependent claims or in the description or the figures may, individually or in any combination, constitute an object of the invention unless the context clearly indicates otherwise.

[0012] The present invention relates to a process for producing metal carbodiimides, wherein the metal carbodiimides satisfy the following chemical formula (1): A x B y (NCN)3 (1), where - A is a metal cation with oxidation state x, - B is a metal cation with oxidation state y, where - x and y are chosen such that A x B y (NCN)3 results in an electrically neutral compound, i.e., where in other words x + y = 6, the procedure comprises the following steps: a) Providing a mixture of AHal m , BHal n and M p NCN, wherein M is selected from zinc, sodium and lithium, wherein Hal is a halogen selected from fluorine, chlorine or bromine, and wherein m, n and p are selected such that AHal m , BHal n and M p NCN each result in electrically neutral compounds; and b) Treating the mixture at a temperature in the range of at least 500 °C.

[0013] The described method thus serves to produce specific metal carbodiimides. In particular, the described method can be used to produce transition metal carbodiimides that have a ternary structure and satisfy the formula (1) described above.

[0014] Regarding the selection of x and y such that A x B y (NCN)3 results in an electrically neutral compound, the condition must be met that x + y = 6.

[0015] Examples of A cations with x = 1 are: Li and Na. These are combined with B cations with y = 5, such as Nb and Ta.

[0016] Examples of A cations with x = 2 are Mg, Ca, Mn, Fe, Co, and Ni. These are combined with B cations with y = 4, e.g., Hf, Zr, and Sn.

[0017] Examples of A cations with x = 3 are Cr, Al, Ga, and In. These are combined with B cations with y = 3, e.g., Lu and Yb.

[0018] Preferably, A can be selected from the group consisting of lithium cations (Li + ), sodium (Na + ), Cobalt (Co 2+ ), Manganese (Mn 2+ ), iron (Fe 2+ ), Calcium (Ca 2+ ), Magnesium (Mg 2+ ), Nickel (Ni 2+ ), Ytterbium (Yb 3+ ), Indium (In 3+ ), Gallium (Ga 3+ ), Aluminium (Al 3+ ) and lutetium (Lu 3+).

[0019] A can be further preferably selected from the group consisting of cobalt cations (Co 2+ ), Manganese (Mn 2+ ), iron (Fe 2+ ), Calcium (Ca 2+ ), Magnesium (Mg 2+ ), Nickel (Ni 2+ ), Ytterbium (Yb 3+ ), Indium (In 3+ ), Gallium (Ga 3+ ), Aluminium (Al 3+ ) and lutetium (Lu 3+ ).

[0020] A can be selected even more preferentially from the group consisting of manganese cations (Mn⁻). 2+ ) and iron (Fe2+ ).

[0021] Preferably, B can be selected from the group consisting of hafnium (Hf 4+ ), Zirconium (Zr 4+ ), tin (Sn 4+ ), Chromium (Cr 3+ ), Niobium (Nb 5+ ) and tantalum (Ta 5+ ),

[0022] B can be further preferred from the group consisting of hafnium (Hf 4+ ), Zirconium (Zr 4+ ), tin (Sn 4+ ), Chromium (Cr 3+ ).

[0023] B can be selected with particular preference from the group consisting of hafnium (Hf 4+ ) and zirconium (Zr 4+ ), where hafnium (Hf 4+ ) may be particularly favored.

[0024] Accordingly, suitable combinations of x and y can be found at x = 1 and y = 5, x = 2 and y = 4, and at x = 3 and y = 3.

[0025] The metal carbodiimides can preferably be selected from the group consisting of MnHf(NCN)3, FeHf(NCN)3, MnZr(NCN)3 FeZr(NCN)3, CoHf(NCN)3, CoZr(NCN)3, MnSn(NCN)3, FeSn(NCN)3, CaHf(NCN)3, MgHf(NCN)3, NiHf(NCN)3, YbCr(NCN)3, InCr(NCN)3, GaCr(NCN)3, AlCr(NCN)3, LuCr(NCN)3, LiNb(NCN)3, NaNb(NCN)3, LiTa(NCN)3, NaTa(NCN)3.

[0026] More preferably, the metal carbodiimides can be selected from the group consisting of MnHf(NCN)3, FeHf(NCN)3, MnZr(NCN)3 FeZr(NCN)3, CoHf(NCN)3, CoZr(NCN)3, MnSn(NCN)3, FeSn(NCN)3, CaHf(NCN)3, MgHf(NCN)3, NiHf(NCN)3, YbCr(NCN)3, InCr(NCN)3, GaCr(NCN)3, AlCr(NCN)3, LuCr(NCN)3.

[0027] Even more preferably, the metal carbodiimides can be selected from the group consisting of MnHf(NCN)3, FeHf(NCN)3, MnZr(NCN)3, and FeZr(NCN)3.

[0028] In one embodiment, A can be specified as manganese. In this case, x equals 2 and y equals 4.

[0029] In another embodiment, A can be iron. In this case, x = 2 and y = 4.

[0030] In another embodiment, B could be hafnium. In this case, x equals 2 and y equals 4.

[0031] In a further embodiment, B can be zirconium. In this case, x equals 2 and y equals 4.

[0032] Furthermore, the process described here is used in particular to produce ternary carbodiimides, which consist of two different metal cations and the carbodiimide anion, as described in greater detail below.

[0033] The metal carbodiimides produced by the process comply with the following chemical formula (1) A x B y (NCN)3 (1),

[0034] The following conditions apply: The metals or metal cations are selected as described above. It has been shown that the described synthesis of the metal carbodiimides is readily achievable, particularly using these metal cations, and that novel substances with advantageous properties are produced, as described below.

[0035] To produce the carbodiimides described above, the process comprises the following steps: a) Providing a mixture of AHal m , BHal n and M p NCN, wherein M is selected from zinc, lithium and sodium, wherein Hal is a halogen selected from fluorine, chlorine or bromine and wherein m, n and p are selected such that AHal m , BHal n and M p NCN each result in electrically neutral compounds; and b) Treating the mixture at a temperature in the range of at least 500 °C.

[0036] According to process step a), a mixture of AHal m , BHal n and M p NCN is provided. Accordingly, the metals to be included in the metal carbodiimide are provided as metal halides. Furthermore, the carbodiimide is provided as metal carbodiimide.

[0037] Again, m, n and p are chosen such that AHal m , BHal n and M p NCN compounds each result in electrically neutral compounds and thus depend in particular on the chosen metal cation A or B or the metal cation M.

[0038] In one embodiment, A may be manganese. In this case, m is 2.

[0039] According to the invention, B is hafnium. Accordingly, n is 4.

[0040] In one embodiment, M can be sodium. In this case, p is 2.

[0041] In a further embodiment, M can be zinc. In this case, p is 1.

[0042] In principle, the metal cations A and B can be selected as described in detail above, since the selection of the corresponding halides is of course the cause of the carbodiimides produced.

[0043] Accordingly, to produce metal carbodiimides, various specific metal cations are reacted side by side with a carbodiimide anion. The type and quantity of the metal cations and halide anions are selected to ensure an electrically neutral compound.

[0044] It has been shown that hafnium is particularly suitable as a metal cation in the production of a ternary carbodiimide compound. The other metal cations can be either manganese cations, iron cations, or one of the other aforementioned cations.

[0045] For the preparation of ternary carbodiimides with formula A x B y (NCN)3 the reactants are preferably in a molar ratio of AHal m : BHal n : M p NCN reacted in a 1:1:3 ratio. However, slight variations in this molar ratio may be necessary to achieve the desired A. x B y to synthesize the (NCN)3 phase, which nevertheless falls within the scope of the present invention. Accordingly, the molar ratio of AHal can be m : BHal n : M pNCN may deviate from 1 : 1 : 3, whereby a deviation of 25 mol-% of each value, starting from the molar ratio of 1 : 1 : 3, is possible in accordance with the invention.

[0046] The selection of the metal halides or metal carbodiimides to be used can be made possible in a manner that is immediately apparent to the person skilled in the art by selecting them from the group of substances to be produced specified above.

[0047] The mixture according to process step a) can be easily produced by blending the respective solids. It can be advantageous to grind the solids to create the mixture. This can enable intimate mixing or bonding of the reactants while simultaneously providing a high surface area for the solids. A suitable particle size can range from ≥ 10 nm to ≤ 1000 nm, typically between ten and several hundred nanometers. Grinding can, in principle, take place in any type of grinding device. Pestles or mortars are examples of suitable methods, particularly for small-scale production.

[0048] This mixture can then be processed as defined in process step b), according to which the mixture is treated at a temperature in a range of at least 500 °C.

[0049] The reaction can preferably be carried out under an inert gas atmosphere. Suitable inert gases or protective gases include, for example, argon or nitrogen, as is known per se, and the invention is in no way limited to these protective gases.

[0050] Suitable treatment durations, which are advantageous for the conversion of the respective substances, can last several hours. Generally, suitable treatment durations range from ≥ 2 to ≤ 48 hours. Such treatment durations enable reproducible conversion and are also feasible on an industrial scale.

[0051] Furthermore, suitable temperature ranges for thermal treatment or for the conversion of the reactants and for the production of the metal carbodiimides according to process step b) can lie within a temperature range of ≥ 500°C to ≤ 700°C. Such a temperature range enables a reliable and reproducible conversion of the reactants to the desired carbodiimide and can also be achieved in known reactors, such as protective gas furnaces. Accordingly, it is clear that the production of the carbodiimides according to the invention is readily possible for a person skilled in the art using known means.

[0052] The desired metal carbodiimide is easily formed as a solid through thermal treatment. This solid is generally stable in air and can be readily purified with water, alcohol (e.g., ethanol), or preferably a water / alcohol mixture.

[0053] The reaction described above enables the generation of a ternary metal carbodiimide compound from a binary metal carbodiimide compound. This involves solid-phase metathesis to produce the desired product. The reaction is described below by way of example, and without limitation, for the specific metal carbodiimides MnHf(NCN)3 and FeHf(NCN)3, which are considered preferred embodiments of the present invention.

[0054] The metal carbodiimides, such as MnHf(NCN)3 and FeHf(NCN)3, were first prepared using the above-described method by solid-phase metathesis reactions between ZnNCN and the corresponding metal chlorides according to the following equation (i): 3 ZnNCN + MCl2 + HfCl4 → MHf(NCN)3 + 3 ZnCl2 ; (M = Mn, Fe) (i)

[0055] The method described above offers a novel approach to the synthesis of previously inaccessible metal carbodiimides. The method is reliable, reproducible, and technically straightforward. Thus, a surprising method has been found for creating carbodiimides with a preferred range of applications. Due to the advantageous properties of the synthesized substances, numerous benefits are offered.

[0056] In particular, the perovskitic carbodiimides with the general formula AB(NCN)3, where A and B are metal cations as defined above and NCN represents the complex carbodiimide dianion, are widely available and readily synthesized using carefully selected reagents and reaction conditions. Furthermore, the method is highly general and will therefore enable the preparation of various members of this class of compounds suitable for applications similar to those of the perovskitic oxides.

[0057] The present invention relates accordingly to metal carbodiimides, wherein the metal carbodiimides satisfy the following chemical formula (1): A x B y (NCN)3 (1), where - A is a metal cation with oxidation state x, - B is a metal cation with oxidation state y, - x and y are chosen such that A x By (NCN)3 results in an electrically neutral connection.

[0058] In particular, the described metal carbodiimides are produced according to the method described above.

[0059] The above applies accordingly.

[0060] The metals or metal cations are selected as described above. It has been shown that the described synthesis of the metal carbodiimides is readily achievable, particularly using these metal cations, and that novel substances with advantageous properties are produced, as described below.

[0061] The metal carbodiimides can preferably be selected from the group consisting of MnHf(NCN)3, FeHf(NCN)3, MnZr(NCN)3 FeZr(NCN)3, CoHf(NCN)3, CoZr(NCN)3, MnSn(NCN)3, FeSn(NCN)3, CaHf(NCN)3, MgHf(NCN)3, NiHf(NCN)3, YbCr(NCN)3, InCr(NCN)3, GaCr(NCN)3, AlCr(NCN)3, LuCr(NCN)3, LiNb(NCN)3, NaNb(NCN)3, LiTa(NCN)3, NaTa(NCN)3.

[0062] More preferably, the metal carbodiimides can be selected from the group consisting of MnHf(NCN)3, FeHf(NCN)3, MnZr(NCN)3 FeZr(NCN)3, CoHf(NCN)3, CoZr(NCN)3, MnSn(NCN)3, FeSn(NCN)3, CaHf(NCN)3, MgHf(NCN)3, NiHf(NCN)3, YbCr(NCN)3, InCr(NCN)3, GaCr(NCN)3, AlCr(NCN)3, LuCr(NCN)3.

[0063] Even more preferentially, the metal carbodiimides can be selected from the group consisting of MnHf(NCN)3, FeHf(NCN)3, MnZr(NCN)3, and FeZr(NCN)3.

[0064] In a preferred embodiment, the metal carbodiimides are selected from the group consisting of MnHf(NCN)3 and FeHf(NCN)3.

[0065] For example, the metal carbodiimide is MnHf(NCN)3.

[0066] Alternatively, the metal carbodiimide can be FeHf(NCN)3.

[0067] In particular, the described metal-carbodiimide compounds have been shown to possess advantageous properties that make them interesting for various applications.

[0068] It has been shown that the ternary metal carbodiimides defined above, with a perovskite AB(NCN)3 composition, crystallize in chiral crystal structures. This alone results in very advantageous properties and application possibilities.

[0069] For example, metal carbodiimides are nonlinearly optically (NLO) active, which is why there is potential for optical applications, for example laser applications.

[0070] Furthermore, the chemical analogy between the dianions NCN suggests 2- (Carbodiimide) and O 2-(Oxide) indicates that, in addition to a variety of perovskitic ABO3 oxides, AB(NCN)3 carbodiimides are readily available. However, it should be emphasized that the carbodiimidic representatives AB(NCN)3, due to their greater chemical covalence and therefore smaller band gaps, are presumably more targeted and thus more reproducible in their application. Accordingly, the carbodiimides according to the invention offer significant advantages over the corresponding oxides.

[0071] Given the important application of perovskitic ABO3 oxides as dielectrics or piezoelectrics in electronic devices, such as smartphones, as ion conductors in battery electrolytes and as photocatalysts in water splitting, a similarly broad application can be expected for the AB(NCN)3 compounds according to the invention, albeit with improved results.

[0072] Currently, the use of perovskite oxides in fields such as information electronics is limited to those oxides that, due to high ionicity (i.e., large band gaps), cannot be used for all applications. In previous technology, the oxide anion (O₂) was used. 2- ) kept constant and only the cations varied, with approximately Sr 2+ , Ti 4+ , or other methods were used, but without the anionic component (O 2- ) to be able to tailor the solution to the application problem. These problems can be effectively solved according to the invention.

[0073] In summary, this offers a wide range of applications in the energy sector, semiconductor technology and information technology.

[0074] Another object of the present invention is therefore the use of the carbodiimides according to the invention in the energy sector, in semiconductor technology and in information technology, in particular based on their optical and electronic properties.

[0075] Light-emitting diodes (LEDs) made from carbodiimidic perovskites would be excellent candidates for next-generation lighting technologies due to their high color purity and, above all, tunable emission wavelengths (carbodiimides allow for chemical tuning of the band gap). In the field of semiconductors, carbodiimidic perovskites are well-suited for use in field-effect transistors (FETs) and other semiconductor devices because of their high charge carrier mobility and tunable band gap (covalence), making them suitable for applications in electronics and optoelectronics, as well as for integration into electronic circuits (logic gates and sensors).

[0076] Semiconducting carbodiimide perovskites are also attractive candidates as electrodes for photoelectrochemical (PEC) water splitting, which enables the large-scale production of renewable hydrogen from water. This is due to their chemical stability and structural flexibility, which allows for precise control and tuning of band gaps and band edges, resulting in excellent sunlight absorption.

[0077] In information technology, carbodiimidic perovskite materials are likely to be suitable for use in non-volatile storage devices due to their high charge carrier mobility and adjustable band gap (covalence), especially since these devices consume little power and are stable over the long term. At the same time, the presence of magnetic elements (e.g., Fe, Mn) makes their use in spintronics a logical step, i.e., for generating spin-polarized charge carriers in spin-based devices such as spin valves and spin transistors.

[0078] The invention is explained below by way of example with reference to the accompanying drawings, wherein the features shown below can represent an aspect of the invention both individually and in combination, and wherein the invention is not limited to the following drawing, the following description and the following embodiment. The Fig. Figure 1 shows a PXRD diffractogram of MnHf(NCN)3; Fig. 2 a PXRD diffractogram of FeHf(NCN)3; Figure 3 shows the comparison of different IR spectra and Fig. 4 an IR spectrum of FeHf(NCN)3. Examples

[0079] The following analytical methods were performed to characterize the produced metal carbodiimides.

[0080] Powder X-ray diffraction (PXRD). PXRD measurements on MnHf(NCN)3 “Method 1”, “Method 2” and FeHf(NCN)3 were performed at room temperature using a calibrated STOE STADI-MP powder diffractometer with flat sample holders (Mo K a1 , linear PSD, 20-range 2-65° with individual steps of 0.005°). Rietveld refinements were performed using GSAS and the EXPGUI interface, as described in Toby, BHJ EXPGUI, a graphical user interface for GSAS. Appl. Crystallogr. 2001, 34, 210-213.

[0081] Infrared spectroscopy (IR). The infrared spectroscopic measurements of the two products were recorded using a Shimadzu IRSpirit FT-IR spectrometer. Production of metal carbodiimides according to the invention

[0082] Preparation of ZnNCN. ZnCl₂ (1.363 g, 10 mmol) was dissolved in water. The hydroxide was then precipitated by the slow addition of 25% NH₃ solution and subsequently redissolved. Separately, H₂NCN (0.841 g, 20 mmol) was also dissolved in water and rapidly combined with the zinc solution. After stirring for several hours, the product was filtered, washed with water and ethanol, and then dried.

[0083] Preparation of Na₂NCN. Under an argon atmosphere, a 6:1 molar mixture of NaNH₂ and C₃H₆N₆ was homogenized using an agate mortar and pestle and then transferred to an aluminum oxide boat. The reaction mixture was heated for 5 hours at 200, 250, and 500 °C in an argon atmosphere. The heating and cooling rates were 2 K / min throughout the entire cycle. The purity of the synthesized material was confirmed by X-ray powder diffraction. Production of MnHf(NCN)3

[0084] Method 1: A mixture of ZnNCN, HfCl4, and MnCl2 with a molar ratio of 3:1:1.2 was carefully ground in an argon-filled glovebox using an agate pestle and mortar and enclosed in an evacuated quartz ampoule. This ampoule was placed in a tube furnace and heated to 600 °C for 8 hours at a heating and cooling rate of 2 K / min. The grayish product, stable in air, was washed with water and ethanol.

[0085] Method 2: In an argon-filled glovebox, a stoichiometric mixture with a molar ratio of 3:1:1 of Na₂, NCN, HfCl₄, and MnCl₂ was carefully crushed using an agate pestle and mortar and enclosed in an evacuated quartz ampoule. This ampoule was placed in a tube furnace and heated to 700 °C for 8 hours at a heating and cooling rate of 2 K / min. The air-stable, grayish product was obtained, and the co-produced NaCl was washed out with water and ethanol.

[0086] Preparation of FeHf(NCN)3. In an argon-filled glovebox, a mixture with a molar ratio of ZnNCN, HfCl4, and FeCl2 was carefully ground with an agate pestle and mortar and placed into an open quartz tube. This tube was then placed in a quartz ampoule and heated to 550 °C in a tube furnace under flowing argon for 8 hours at a heating and cooling rate of 2 K / min. The dark red product, stable in air, was washed with water and a 25% NH3 solution to remove unreacted ZnNCN.

[0087] MnHf(NCN)3 and FeHf(NCN)3 were thus initially prepared by solid-phase metathesis reactions between ZnNCN and the corresponding metal chlorides according to equation (i): 3 ZnNCN + MCl2 + HfCl4 → MHf(NCN)3 + 3 ZnCl2 ; (M = Mn, Fe) (i)

[0088] The two ternary phases proved to have different thermal stability and therefore required different synthesis temperatures: 600 °C for the Mn-containing compound and 550 °C for the Fe-containing compound. The formation of the two ternary phases is favored by the low melting point (290 °C) and low sublimation temperature (500 °C) of the co-produced metathetic salt ZnCl₂, which precipitates in the cold part of the ampoule.

[0089] The compounds produced were processed as described in the Fig. Figures 1 to 4 are shown and characterized.

[0090] The two compounds could be characterized as follows.

[0091] The Fig. Figure 1 shows a PXRD diffractogram of MnHf(NCN)3, where the x-axis represents the 2θ value in ° and the y-axis represents the dimensionless intensity. More precisely, the Rietveld fit of MnHf(NCN)3 of "Method 2" to PXRD data is shown, displaying the observed (A), calculated (B), and different (F) intensities. The Bragg positions of MnHf(NCN)3 (C) are indicated by vertical markers. Additional markers (D) refer to a 4.47(5) wt% HfO2 (Fm3m) and (E) to an 11.1(8) wt% HfO2 (P21 / c) impurity.

[0092] The Fig. Figure 2 shows a PXRD diffractogram of FeHf(NCN)3, where the x-axis represents the 2θ value in ° and the y-axis represents the dimensionless intensity. More precisely, the Rietveld fit of FeHf(NCN)3 with P6322 symmetry to PXRD data is shown, with observed (A), calculated (B), and different (F) intensities. The Bragg positions of FeHf(NCN)3 (E) are indicated by vertical markers. Markers D refer to 4.87(9) wt% HfO2 in Pbcm, and markers E to 10.7(7) wt% HfO2 in P21 / c.

[0093] Fig. Figure 3 shows IR spectra, where the x-axis represents the wavenumber in [cm²]. -1 ] indicates the dimensionless transmission. IR spectra of MnHf(NCN)3 (B) compared to a symmetric carbodiimide in MnNCN (A), an asymmetric cyanamide (C) in Li2MnSn2(NCN)6, and a DFT-generated theoretical (D) IR spectrum (left). Coordination environments of NCN 2-Anions in MnNCN (top), MnHf(NCN)3 (middle) and Li2MnSn2(NCN)6 (bottom) (right).

[0094] Fig. Figure 4 shows an IR spectrum of FeHf(NCN)3, where the x-axis represents the wavenumber in [cm⁻¹]. -1 ] indicates and the Y-axis represents the dimensionless transmission.

[0095] Structural description. From a broader perspective, the crystal structures of both MnHf(NCN)3 and FeHf(NCN)3 can be described as a hexagonal close packing of [N=C=N] 2- Rods are described, with the metal cations partially occupying the octahedral spaces in an ordered manner.

[0096] This results in honeycomb-like layers of edge-dividing metal octahedra with a dispersive distribution of Hf. 4+Metal cations. The ordering scheme in the plane is identical to that observed in the LiNbO3 structure, which in turn can be considered a cation / vacancy structure variant of the NiAs type or a highly distorted perovskite derivative.

[0097] In summary, the successful synthesis of two novel ternary transition metal carbodiimides, MnHf(NCN)3 and FeHf(NCN)3, which have the basic composition AB(NCN)3, and which were prepared by solid-state metathesis under relatively mild conditions, was demonstrated. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Zitierte Patentliteratur

[0000] CN 115441046

[0007] EP 3 104 437 A1

[0008] Zitierte Nicht-Patentliteratur

[0000] Bhalla, A., Guo, R. & Roy, R. The perovskite structure - a review of its role in ceramic science and technology. Mat Res Innovat 4, 3-26 (2000

[0004] Shellaiah, M.: Review on Sensing Applications of Perovskite Nanomaterials Chemosensors; 2020, 8, 55

[0005] Launay, M.: A Theoretical Study on the Structures and Energetics of Hypothetical TiM(NCN)3 Compounds of the 3d Transition Metals J Comput Chem 26: 1180-1188, 2005

[0006] Toby, B. H. J. EXPGUI, eine grafische Benutzeroberfläche für GSAS. Appl. Crystallogr. 2001, 34, 210-213

[0080]

Claims

[1] Method for producing metal carbodiimides, characterized by , that the metal carbodiimides satisfy the following chemical formula (1): A x B y (NCN)3 (1), where - A is a metal cation with oxidation state x, - B is a metal cation with oxidation state y, where - x and y are chosen such that A x B y (NCN)3 results in an electrically neutral compound, the procedure comprises the following steps: a) Providing a mixture of AHal m , BHal n and M p NCN, wherein M is selected from zinc, lithium and sodium, wherein Hal is a halogen selected from fluorine, chlorine or bromine and wherein m, n and p are selected such that AHal m , BHal n and M p NCN each result in electrically neutral compounds; and b) Treating the mixture at a temperature in the range of at least 500 °C. [2] Method according to claim 1, characterized by , that the molar ratio of AHal m : BHal n : M p NCN is at 1 : 1 :

3. [3] Method according to one of claims 1 or 2, characterized by , that A is manganese or iron. [4] Method according to one of claims 1 or 2, characterized by that B is hafnium or zirconium. [5] Method according to any one of claims 1 to 4, characterized by , that according to process step a) a mixture is produced by grinding AHal m , BHal n and M p NCN is performed. [6] Method according to any one of claims 1 to 5, characterized by , that process step b) takes place at a temperature in a range of ≥ 500°C to ≤ 700°C. [7] Metal carbodiimides, characterized by , that the metal carbodiimides of the following chemical formula (1) are satisfied: Ax B y (NCN)3 (1), where - A is a metal cation with oxidation state x, - B is a metal cation with oxidation state y, where - x and y are chosen such that A x B y (NCN)3 results in an electrically neutral connection. [8] Metal carbodiimides according to claim 7, characterized by , that A is selected from the group consisting of cations of lithium, sodium, cobalt, manganese, iron, calcium, magnesium, nickel, ytterbium, indium, gallium, aluminum and lutetium. [9] Metal carbodiimides according to claim 7 or 8, characterized by , that B is selected from the group consisting of hafnium, zirconium, tin, chromium, niobium and tantalum. [10] Metal carbodiimides according to any one of claims 7 to 9, characterized bythat the metal carbodiimides are selected from the group consisting of MnHf(NCN)3, FeHf(NCN)3, MnZr(NCN)3 FeZr(NCN)3, CoHf(NCN)3, CoZr(NCN)3, MnSn(NCN)3, FeSn(NCN)3, CaHf(NCN)3, MgHf(NCN)3, NiHf(NCN)3, YbCr(NCN)3, InCr(NCN)3, GaCr(NCN)3, AlCr(NCN)3, LuCr(NCN)3, LiNb(NCN)3, NaNb(NCN)3, LiTa(NCN)3, NaTa(NCN)3. [11] Metal carbodiimides according to claim 10, characterized by , that the metal carbodiimides are selected from the group consisting of MnHf(NCN)3, FeHf(NCN)3, MnZr(NCN)3, FeZr(NCN)3. [12] Metal carbodiimides according to any one of claims 7 to 11, characterized by that the metal carbodiimides exist in chiral crystal form. [13] Use of the metal carbodiimides according to any one of claims 7 to 12 in the energy sector, in semiconductor technology and in information technology, in particular as lasers, as dielectrics or piezoelectrics in electronic devices, as ion conductors in battery electrolytes, as photocatalysts in water splitting, as components in semiconductor devices, as components in non-volatile storage devices.

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