Ternary Amide Research Articles

Caesiumamidometallate des gadoliniums, ytterbiums und yttriums mit perowskitverwandten Atomanordnungen Cs 3M 2(NH 2) 9

In the Cs-M-NH 3 systems with M ≡ Gd, Yb and Y the ternary amides Cs 3M 2(NH 2) 9 have been detected by high pressure syntheses in ammonia and X-ray phase analysis. The ytterbium and yttrium compounds were found to have hexagonal perovskite structure using X-ray analysis. The hydrogen positions could only be determined for Cs 3Y 2(NH 2) 9. In Cs 3Gd 2(NH 2) 9 the Cs + and NH 2 − ions form a distorted close packing with the sequence ABACBC… and gadolinium occupies hexagonal face sharing anion double octahedra, [Gd 2(NH 2) 9] 3−. The IR spectra of the compounds have been measured. The crystal chemistry of the caesiumamidometallates is discussed with respect to the perovskite-like atomic arrangement.

Darstellung und eigenschaften der amidomagnesate des kaliums und rubidiums K 2[Mg(NH 2) 4]- und Rb 2[Mg(NH 2) 4]-Verbindungen mit isolierten [Mg(NH 2) 4] 2−-tetraedern

In the systems KMgNH 3 or RbMgNH 3, well-crystallized ternary amides were prepared by the reaction of the metals with NH 3 as reagent and solvent at an NH 3 pressure of 2 kbar and at a temperature of about 150 °C within 3 days. The X-ray phase analysis led to only one ternary amide in the corresponding systems. The two isotypic compounds are characterized by the following crystallographic data: K 2[Mg(NH 2) 4], P2 1 C , Z= 4, a = 7.455(2) A ̊ , b = 7.024(2) A ̊ , c = 13.545(9) A ̊ , β = 105.6(1)°; Rb 2 [Mg(NH 2) 4], P2 1 c , Z = 4, a = 7.809(1) A ̊ , b = 7.054(1) A ̊ , c = 14.004(3) A ̊ , β = 105.99(8)°. For the potassium compound the positions of the hydrogen atoms of the amide ions could also be determined. This allowed the interpretation of the proton-cation interaction.

Struktur und eigenschaften der ternären metallamide NaCa(NH 2) 3, KBa(NH 2) 3, RbBa(NH 2) 3, RbEu(NH 2) 3 und RbSr(NH 2) 3

The reaction of the metals sodium and calcium, potassium and barium, rubidium and barium, rubidium and europium as well as rubidium and strontium with supercritical ammonia at about 5 kbar in autoclaves at temperatures from 200 to 500 °C gave well-crystallized amides. The X-ray phase analysis revealed only one ternary amide in the corresponding systems. For the compounds the crystallographic data summarized above were obtained from single-crystal investigations. A structure determination was carried out for the first four compounds. Their atomic arrangements are discussed for comparison. IR spectra of RbEu(NH 2) 3 and RbSr(NH 2) 3 are interpreted.

Über kalium- und rubidiumamidometallate des Europiums, Yttriums und Ytterbiums, K 3M(NH 2) 6 und Rb 3M(NH 2) 6

Potassium and rubidium amidometallates of europium, yttrium and ytterbium, K 3M(NH 2) 6 and Rb 3M(NH 2) 6, were prepared in a well-crystallized form by the reaction of the corresponding metals in supercritical ammonia as reactant and solvent. X-ray structure determinations gave a series of isotypic compounds: K 3Y(NH 2) 6, K 3Yb(NH 2) 6, Rb 3Eu(NH 2) 6 and Rb 3Y(NH 2) 6. Rb 3Yb(NH 2) 6 has a structure closely related to these. The atomic arrangements of these five ternary amides are compared with one another. In addition, they are characterized by their IR spectra.

Strukturverwandtschaft des dicaesiumamidomagnesats, Cs 2[Mg(NH 2) 4], zum β-K 2SO 4-Typ

The investigation of the caesium amide-magnesium amide system reveals one ternary amide, Cs 2[Mg(NH 2) 4]. Single crystals of this compound were prepared in autoclaves at 415 K and an NH 3 pressure of 2 kbar by the reaction of the metals with NH 3 for 2 days. An X-ray investigation showed isolated tetrahedral [Mg(NH 2) 4] 2− ions which are connected three dimensionally by caesium. The structure is closely related to the β-K 2SO 4 type of structure. This is shown by using space group relations.

Über ein trilithiumnatriumamid, Li 3Na(NH 2) 4, eine verbindung mit lithiumamidverwandter struktur

In the LiNH 2-NaNH 2 system, three ternary amides were determined by X-ray investigation: LiNa 2(NH 2) 3, Li 3Na(NH 2) 4 and Li 5Na(NH 2) 6. The compounds were obtained by the reaction with supercritical ammonia of the metals lithium and sodium in molar ratios from 1:3 to 3:1. The atomic arrangement is given for Li 3Na(NH 2) 4 at 180 and 293 K from single-crystal data.

Darstellung und eigenschaften des caesiumbarium-amids, CsBa(NH 2) 3: Strukturverwandtschaft zum NH 4CdCl 3-Typ

In the caesium amide-barium amide system the ternary amide CsBa(NH 2) 3 was synthesized in the form of needle-like single crystals by the reaction of the corresponding metals with NH 3 at an NH 3 pressure of 5 kbar and at 473 K within 11 days. The X-ray structure determination shows strings of edge-sharing anion double octahedra containing the barium atoms, while caesium connects them three dimensionally. The atomic arrangement is discussed in comparison with that of the NH 4CdCl 3 type of structure.

Über ein cäsiumheptaamidodilanthanat CsLa 2(NH 2) 7

The reaction of the metals caesium and lanthanum with supercritical NH 3 at 470–570 K and 4.0–6.0 kbar gave within 3–100 days well-crystallized ternary amides. From an X-ray single-crystal investigation the ternary compound with the highest amount of lanthanum was found to be CsLa 2(NH 2) 7. The synthesis and the atomic arrangement as well as the IR spectrum and the thermal behaviour of this amide are discussed in this work.

Struktur und eigenschaften von perowskitartigen cäsiumamidometallaten des cers, neodyms und samariums Cs 3Ln 2(NH 2) 9

Ternary amides with the chemical formula Cs 3Ln 2(NH 2) 9 with Ln  Ce, Nd and Sm were prepared in a well-crystallized form by the reaction of the metals with NH 3 as solvent and reactant at 430–530 K and an NH 3 pressure of 2–6 kbar for 7–100 d. No further amidometallates could be found in these systems. For the data resulting from X-ray investigations on single crystals, see “Zusammenfassung”. The cerium and neodymium compounds exist in a stable [I] and a high temperature [II] or a high pressure modification [II]. In all structures the atoms occur in perovskite-like arrangements. Cs + and NH 2 − ions together form slightly distorted close packings with different stackings. The lanthanide ions occupy two face-sharing anion octahedra as given by [Ln 2(NH 2) 9 ] 3−. Measurements of the magnetic behaviour (4–293 K) of Cs 3Nd 2(NH 2) 9[II] suggest a three-dimensional interaction between the Nd 3+ ions. The IR spectra of the compounds were obtained and interpreted. Thermal decomposition of the caesium amidometallates leads in one step to LnN and undecomposed CsNH 2. All the results are discussed and compared.

Über natrium- und kaliumamidometallate des calciums, strontiums und europiums

The systems Na/M/NH 3 with M = Ca, Sr, Eu, and K/Sr/NH 3 were investigated. Under the conditions of the ammonothermal synthesis at temperatures between 570 and 670 K and pressures of 5000 bar, the following ternary amides —besides the binary compounds —can be prepared: NaCa(NH 2) 3, KSr(NH 2) 3, Na 2Sr 3(NH 2) 8, and Na 2Eu 3(NH 2) 8. (For the crystal data see Zusammenfassung.) In the four compounds the anions are in a distorted cubic closepacking. The cations are in octahedral interstices with partially statistical occupancy. The crystal chemistry of the compounds is compared with such related amidometallates as KEu(NH 2) 3 and Na 3La(NH 2) 6. The thermal degradation of the ternary alkaline earth metal amides leads to the imides together with undecomposed alkali metal amide. The europium compound gives EuN directly with additional evolution of hydrogen.

Amides of the Alkali and the Alkaline Earth Metals

AbstractFollowing preparative work, the behavior of amides towards excess ammonia (ammoniate formation) and on removal of ammonia (degradation to imides)was studied particularly with regard to the solid state (crystal structure) and the transition to the liquid phase (melting point). Energy relationships are discussed on the basis of enthalpies of formation. Studies on ternary amides and imides are still in the initial stage. – Emphasis is laid here on the establishment of parallels between amides and hydroxides as well as between the aquo and ammono systems, and also on the differences between the amides with their dipolar NH2‐ anion, and the halides. The results, although still incomplete, permit a survey to be given of experimental data with the aid of information obtained from the pertinent literature.