Orthorhombic Space Group Research Articles

High-pressure synthesis and crystal structure determination of Tb2SiB2O8

Abstract We report the high-pressure/high-temperature synthesis (11 GPa, 1300 °C) of the new compound Tb2SiB2O8. This rare earth borosilicate crystallizes in the orthorhombic space group Pbcn (no. 60) with the unit cell parameters a = 13.2480(3), b = 4.3904(1), and c = 9.1611(3) Å. It is built up of corner-sharing [BO4] tetrahedra forming infinite chains, that are connected to layers via [SiO4] tetrahedra. The layers are connected via [TbO7] polyhedra.

Growth of Ru-doped β-FeSi2 polycrystalline thin films by RF magnetron sputtering

Ternary silicide β-(Fe1−x Ru x )Si2 polycrystalline thin films were fabricated by RF magnetron sputtering. The crystal structure of β-(Fe1−x Ru x )Si2 was the same orthorhombic (space group: Cmca) as β-FeSi2 in the Ru composition of 0 ≤ x ≤ 0.63. The lattice constants increased with increasing Ru composition, and Vegard’s law was obtained. The wavenumber of the Raman line of Fe−Fe and Fe−Si vibrations shifted to a lower wavenumber with increasing Ru composition. The 1.5 μm photoluminescence (PL) was observed in Si/β-(Fe1−x Ru x )Si2/Si double heterostructure (DH) with x = 0.57. The PL lifetime of the Ru-doped DH sample was shorter than that of the β-FeSi2 (x = 0) DH sample.

New members of the family of l-cysteine-based nonlinear optical crystals-(l-CysH)I, (l-CysH)I·H2O and (l-CysH···l-Cys)I·0.5H2O

The salts formed in the l-cysteine–HI–H2O system were studied. Three salts were obtained as single crystals, namely, anhydrous l-cysteinium iodide (l-CysH)I, l-cysteinium iodide monohydrate (l-CysH)I·H2O and l-cysteinium···l-cysteine iodide hemihydrate (l-CysH···l-Cys)I·0.5H2O, which is a new salt with dimeric cation. Crystal structures of all three salts were solved: anhydrous and hydrated iodides crystallize in the orthorhombic space group P212121, whereas (l-CysH···l-Cys)I·0.5H2O crystallizes in the monoclinic space group I2. The dimeric cation is formed by a very short O–H···O hydrogen bond with (O···O) of 2.436(3) Å. The crystal structures were compared with those of other crystalline l-cysteine halogenides l-CysH(l-CysH···l-Cys)F(F···HF), (l-CysH···l-Cys)Cl, (l-CysH···l-Cys)Br, (l-CysH)Br·H2O (previously studied by us), and (l-CysH)Cl·H2O (previously reported in literature). In addition to crystal structure analysis by X-ray diffraction techniques, infrared and Raman spectra were registered and discussed. Second harmonic generation characteristics by these iodides were measured for powders and compared with those reported for chlorides and bromides.

On red tin (II) oxide: temperature‐dependent structural, spectroscopic, and thermogravimetric properties

AbstractPolycrystalline red tin(II)oxide (RSO) has been synthesized by a fast reflux method. X‐ray powder diffraction (XRPD) data Rietveld refinement confirms the orthorhombic space group Cmc21 (Z=8). The presence of 5 s2 lone electron pair (LEP) of the Sn2+ cation results in layers of highly distorted SnO4 tetrahedra with an averaged Wang‐Liebau eccentricity (WLE) parameter of 4.3(1) x10−5 as a measure of the stereochemical activity. The significantly different Sn−O bond distances demonstrate the under‐bonding nature of both the tin and the oxygen atoms in the SnO4 coordination. The band gap of red tin(II)oxide is found to be 1.75(1) eV which is compared with those of blue‐black tin(II) (BSO) and white tin(IV) oxide (WSO) based on the UV‐Vis diffuse reflectance spectral data. Temperature‐dependent XRPD reveals the phase transitions, which is complemented by thermogravimetric and differential scanning calorimetry (TG/DSC) investigations. Moreover, in‐situ Raman spectroscopy additionally hints to an intermediate phase either of Sn2O3 or Sn3O4 appears within a short temperature range before the RSO to BSO transition occurs. Due to axial negative thermal expansion for the b‐lattice parameter RSO exhibits nearly a zero thermal expansion coefficient for a given temperature range above room temperature.

Crystal engineering of Pb(II)-salen coordination polymer enforced for the selective fluorescence NACs sensing activity in a dispersed aqueous medium: A combined experimental and theoretical DFT monologue

A new 1D coordination polymer (CP), [(SCN)Cd(L1)Pb(NCS)]n (1) was synthesized using N2O4-based Scaffold (H2L1 = N, N’-bis(3-methoxysalicylidenimino)-1,3-diaminopropane) and structurally characterized using various analytical instruments. X-ray structure disclosed complex (1) crystallize in the Orthorhombic space group P212121 with Z=4. The crystal structure contains heteronuclear units of [(SCN)Cd(L1)Pb(NCS)]n, linked by a μ1,1,3 thiocyanate (SCN−) bridging. Here weak S···S chalcogen, Pb···S tetrel bonding with two C-H···π(SCN) and one C-H···π(arene) like interactions are vividly observed. The QTAIM/NCI diagram successfully explains the nature of these contacts. Hirshfeld surface (HS) and 2D fingerprint plots analysis has described the non-covalent supramolecular features. The H…H interactions dominate the solid-state crystal structure. The complex fluorescence behaviour is eventually quenched in the presence of explosive nitroaromatic compounds. Complex (1) retained high fluorescence sensitivity and selectivity only for organo-toxin trinitrophenol (TNP). The Stern-Volmer equation evaluated the enhancement of the fluorescence mechanism, the limit of detection (LOD), and the quenching constant (KSV), which for TNP is 6.92 × 104 M−1. The turn-off fluorescence sensing mechanism is explained by (a) AIM/RDG surface interactions energy, (b) Charge-transfer complex, (b) Photo-induced electron transfer (PET) through the HOMO-LUMO approach, (c) Fluorescence resonance energy transfer (FRET), and (d) 1H NMR titration. Notably, the active dynamic sensing is due to a decrease in fluorescence lifetime after the successive addition of TNP with the polymer. Finally, the title complex (1) is employed as a quenched fluorescence response sensor for detecting TNP in a dispersed aqueous medium.

New Room-Temperature Molecular Ferroelectric (C6H16N2O)CdBr4·H2O with Preferable Luminescent Properties

Organic–inorganic hybrid materials are easy to modify, which makes it possible to construct multifunctional ferroelectrics directionally and apply the built-in electric field and switching properties of ferroelectrics to multidisciplinary fields. Particularly, the coupling of photoluminescence and ferroelectricity in a single hybrid material facilitates its novel applications in lighting sensors, memory devices, and other multifunctional applications. Based on the photoluminescent molecule 4-(2-aminoethyl) morpholine (AEM), here, a room-temperature ferroelectric (C6H16N2O)CdBr4·H2O (AEM-CdBr4) is designed and obtained, which crystallizes in a polar orthorhombic space group of Pca21. A reversible ferroelectric–paraelectric phase transition was confirmed at 353 K through experimental results, such as differential scanning calorimetry (DSC) curves, variable-temperature Raman spectroscopy, and photoluminescence (PL) spectroscopy. The crystal exhibits ferroelectricity at room temperature with a saturation polarization of approximately 8 μC/cm2. The photoluminescence of compound AEM-CdBr4 is mainly derived from the monomeric fluorescence emission of the AEM molecule and is not directly related to the energy band structure of the crystal. This room-temperature molecular-type ferroelectric AEM-CdBr4 with photoluminescence will provide new ideas for the design of new multifunctional ferroelectrics.

Crystallization, structural study and analysis of intermolecular interactions of a 2-aminobenzoxazole–fumaric acid molecular salt

The new organic salt, 2-aminobenzoxazol-3-ium 3-carboxyprop-2-enoate, C7H7N2O+·C4H3O4 −, of the two bioactive compounds 2-aminobenzoxazole and fumaric acid, crystallizes in the orthorhombic space group Pbca using classical evaporation of their solution in water. The usual topological analysis revealed four classical (N—H...O and O—H...O) and two non-classical (C—H...O) hydrogen bonds in the structure. Stacking was found as well for a pair of 2-aminobenzoxazolium cations. A Hirshfeld surface analysis including the two-dimensional fingerprint plots was performed to define the residual π–π interactions and to quantify the influences of different types of interactions by means of topological analysis. Analysis of the pairwise interaction energies was used to prove the formation of the corrugated paired layers of cation–anion dimers parallel to the plane (001) as a basic structural motif in the topological, as well as in the energetic structure of the crystal. It showed that the layers are connected by the hydrogen bonds inside and by stacking and π–π interactions and general dispersion between them.

Li2 Ba4 Al2 Ta2 N8 O, the First Barium Nitridoalumotantalate with BCT-Zeolite Type Structure.

Single-crystals of Li2 Ba4 Al2 Ta2 N8 O:Eu2+ were synthesized from Ba3 N2 , Al2 O3 , Li3 N, Eu2 O3 , and lithium metal by a high-temperature solid-state reaction in a weld shut tantalum ampule. The crystal structure of Li2 Ba4 Al2 Ta2 N8 O was determined by single-crystal X-ray diffraction and it crystallizes in the orthorhombic space group Pnnm (no. 58) with the lattice parameters a=1006.71(3), b=1026.58(3), c=607.10(2) pm, and a volume of V=0.62742(3) nm3 . The compound is built up from AlN4 and TaN4 tetrahedra, which form a three-dimensional network corresponding to the BCT-zeolite type structure. Li2 Ba4 Al2 Ta2 N8 O is homeotypic to Li2 Sr4 Si4 N8 O and Li2 Sr4 Al2 Ta2 N8 O but, additionally, it could be successfully doped with the activator ion Eu2+ and hence features an experimental observed overall emission at λmax =565 nm (fwhm=89 nm) consisting of a superposition of two adjusted emission bands at λmax =557 nm (fwhm=69 nm) and at λmax =604 nm (fwhm=102 nm).

The Halogen Effect on the Magnetic Behaviour of Dimethylformamide Solvates in [Fe(halide-salEen)2]BPh4

Complexes [Fe(X-salEen)2]BPh4·DMF, with X = Br (1), Cl (2), and F (3), were crystallised from N,N′-dimethylformamide with the aim of understanding the role of a high boiling point N,N′-dimethylformamide solvate in the spin crossover phenomenon. The counter ion was chosen for only being able to participate in weak intermolecular interactions. The compounds were structurally characterised by single crystal X-ray diffraction. Complex 1 crystallised in the orthorhombic space group P212121, and complexes 2 and 3 in the monoclinic space group P21/n. Even at room temperature, low spin was the predominant form, although complex 2 exhibited the largest proportion of the high-spin species according to both the magnetisation measurements and the Mössbauer spectra. Density Functional Theory calculations were performed both on the periodic solids and on molecular models for complexes 1–3 and the iodide analogue 4. While all approaches reproduced the experimental structures very well, the energy balance between the high-spin and low-spin forms was harder to reproduce, though some calculations pointed to the easier spin crossover of complex 2, as observed. Periodic calculations with the functional PBE led to very similar ΔEHS-LS values for all complexes but showed a preference for the low-spin form. However, the single-point calculations with B3LYP* showed, for the model without solvate, that the Cl complex should undergo spin crossover more easily. The molecular calculations also reflected this fact, which was more clearly defined when the cation–anion–solvate model was used. In the other models there was not much difference between the Cl, Br, and I complexes.

Temperature and pressure dependence of the Yb valence state in YbMn∼0.17Si∼1.89

Single crystals of the non-stoichiometric YbMn∼0.17Si∼1.89 intermetallic compound were investigated by room-temperature x-ray diffraction as well as by temperature and pressure-dependent x-ray absorption experiments at the Yb L3 edge. The crystal structure can be described in the orthorhombic space group Cmcm or in the non-centrosymmetric P21 monoclinic space group. In both cases, the cell comprises two Yb sites of identical multiplicity with close coordination numbers and interatomic distances. The average Yb valence is found independent of temperature νav ∼ 2.42. Such a low Yb valence is hardly compatible with the occurrence of local magnetism on Yb inferred from a previous study. The pressure dependence of the Yb valence at 10 K does not reveal any first-order transition. The average Yb valence increases continuously under pressure but remains far from trivalency (νav ∼2.63) even under the highest external pressure used of 37 GPa.

Spin Crossover Coordination Polymers with Pyridine-Like Modification through Selective Guest Molecules

A porous 3D FeII coordination polymer made of 4,4′-bipyridine ligands (bipy) and [N(CN)2]− (dca) organic bridges, [Fe(bipy)2dca]ClO4·CHCl3·CH3OH (1·CHCl3·CH3OH), has been synthesized as single crystals, by a slow diffusion technique at room temperature. Single-crystal X-ray diffraction analysis has shown that the structure of 1·CHCl3·CH3OH presents large volume values of porosity (1790 Å3 per iron atom). It crystallizes in the orthorhombic Cmc21 space group but undergoes a phase transition to Cmca at 298 K, presumably due to solvent release. According to magnetic data, this material displays a gradual spin crossover behavior, along with a thermal hysteresis loop of 15 K around 190 K. However, when lattice solvent molecules are removed, the magnetic behavior changes drastically resulting in more gradual spin conversion or even silencing the spin crossover behavior of the as-synthesized complex (1·CHCl3·CH3OH), evidencing the influence of guest molecules on the magnetic properties by host–guest interactions. This property was confirmed by spatiotemporal optical microscopy studies, performed on several single crystals. The generation of a host lattice that interacts with exchangeable guest species in a switchable fashion has implications for the generation of previously undeveloped advanced materials with applications in areas such as molecular sensing.

Pseudohalide coligands guided structural motifs, magnetism and BSA-interactions of copper(II) complexes derived from 1,3-dimethy-6-aminouracil

Two novel copper(II) complexes with mononuclear (1) and 1D polynuclear (2) structural motifs were synthesized using the novel planar tridentate ligand 1,3-dimethyl-5-(thiazolyl-azo)-6-aminouracil, H2L (triclinic, PĪ space group and Z = 2) and pseudohalide coligands, namely azido and thiocyanato ligands. 1 is a monomeric-azo-azido complex with the monoclinic crystal system and P21/n space group, whereas 2 is a 1D polynuclear coordination polymer of Cu(II)-azo-µ-SCN (µ-SCN is bonded in the end-to-end (anti mode) manner) with the orthorhombic crystal system and Pbca space group. The crystallographic study, magneto-structural study and EPR spectra revealed distinctly that both complexes possess a slightly distorted square-pyramidal geometry about the Cu(II) ion. The observed and/or theoretical TDDFT bands show the nature of multiple intraligand, ligand-to-metal, metal-to-ligand charge transfer and d-d transitions. Direct current (dc) variable-temperature magnetic susceptibility measurements on polycrystalline samples of 1 and 2 were carried out in the temperature range 1.8–300 K. The copper(II) ions remain non-interacting at 300 K (χmT: 0.417 cm3 mol−1 K for 1 and 0.361 cm3 mol−1 K for 2). The Weiss constant for 1 is −2.3 K and for 2 it is 0.96 K, indicating that weak antiferromagnetic and weak ferromagnetic interactions exist in 1 and 2, respectively. As expected, complex 1 exhibits an intermolecular type of interaction (zJ′ = −1.37(1) cm−1), whereas 2 exhibits an intramolecular magnetic interaction (J = 1.17(2) cm−1) between the Cu(II) ions. The cause of the weak ferromagnetic coupling in 2 may be due to the orthogonality of the magnetic orbitals (dx2-y2) involved in the equatorial-axial singly bridging SCN moiety. All the compounds show excellent binding interactions (KA) with BSA, with the order complex 1 (1.993 × 104 M−1) > complex 2 (6.072 × 103 M−1) > free ligand (2.619 × 103 M−1).

Elucidating elusive quaternary selenide EuCeCuSe3: Synthesis, crystal structure, properties and theoretical studies

We report on the novel heterometallic quaternary selenide EuCeCuSe3, the fabrication of which has been a challenge until this work. The structure of the reported selenide was elucidated from the powder X-ray diffraction data, which revealed the formation of EuCeCuSe3 with excellent yield (96.7%) accompanied with a minor fraction of CeSe2 (3.3%), and was best solved in orthorhombic space group Pnma with the BaLaCuS3 structural type. Thus, the crystal structure of the title compound completes the row of the heterometallic quaternary selenides EuRECuSe3 (RE = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y), of which the cerium-based derivative exclusively belongs to the BaLaCuS3 structural type. The distortion of the CuSe4 polyhedron was compared for the whole series of EuRECuSe3 compounds using the τ4-descriptor for four coordinated ions, which revealed the highest degree of distortion for the Ce3+-containing selenide, followed by the La3+-based derivative. Furthermore, the crystallographic and geometrical parameters of the reported selenide were discussed in comparison to the Ce3+-based sulfides SrCeCuS3 and EuCeCuS3. Ab initio calculations of the crystal structure, a phonon spectrum and elastic constants for the crystal of EuСeCuSe3 were also performed. The types and wavenumbers of fundamental modes were determined and the involvement of ions participating in the phonon modes was assessed. The experimental IR spectrum of the reported selenide was interpreted and found to be in agreement with the calculated spectrum. The experimental direct band gap of EuCeCuSe3 was measured to be 1.36 eV that is consistent with the concept of its origin due to interband transitions between orbitals emerging mainly from 4f (valence band) and 5d (conduction band) levels of the Eu2+ cation. The dependence of the Young's modulus on the direction demonstrates the anisotropy of the elastic properties, while the Vickers hardness for EuCeCuSe3 was calculated to be 5.2 GPa. Finally, the title compound is paramagnetic above 4 K.

Spontaneous exchange bias and large dielectric constant in Bi0.8Tb0.2Fe0.8Mn0.2O3 multiferroic

The structural, dielectric, and magnetic properties of Bi0.8Tb0.2Fe0.8Mn0.2O3 have been studied in detail. A structural shift from rhombohedral (space group R3c) to orthorhombic (space group Pn21a + Pnma) phase is observed with doping. The substitution of Mn and Tb gives a very large value of the dielectric constant. It has been demonstrated that the observed spontaneous exchange bias is larger than the conventional exchange bias at room temperature. Moreover, doping reduces the Neel temperature from 643 to 521 K and magnetization increases. Thermoremanent magnetization studies at room temperature show that the system is composed of an interfacial layer of an antiferromagnetic core and a two-dimensional diluted antiferromagnet shell with a net magnetization under the field. Furthermore, the system's reasonable HEB and HC values at room temperature make it intriguing and appealing for a variety of multifunctional devices.

New Cyanido-Bridged Complexes of Zn(II) and/or Ag(I) with TPymT and Tptz Ligands: Synthesis, Structural and Fluorescent Properties

The use of two triazine-derived pincer ligands led to the obtaining of a heterometallic compound and of an unexpected 3D coordination polymer (CP). Therefore, by reacting 2,4,6-tri(2-pyridyl)-1,3,5-triazine (tptz) with Zn(NO3)2 and K[Ag(CN)2], the cyanido-bridged [Ag(CN)(m-CN)]2[Zn(tptz)(H2O)] (1) trinuclear complex was formed. Compound 1 crystallizes in the orthorhombic polar space group Aea2 and the crystal packing involves argentophilic interactions. When 2,4,6-Tris(2-pyrimidyl)-1,3,5-triazine (TPymT) was used as a ligand, along with the same precursors as for 1, a 3D CP was assembled, [Ag6(CN)6(TPymT)2] (2). The formation of 2 was favored, most likely, by the dicyanoargentate(I) ion dissociation and its interesting topology is due to the bridging cyanide ligands and argentophilic interactions. The fluorescence of both compounds was studied and compared to the emission features of their ligands. For the two coordination compounds, ligand-centered fluorescence data are discussed.

Crystal structure of dibenzo[c,e]thiepine-5(7H)-thione

The title compound, C14H10S2, was prepared from dibenzo[c,e]oxepine-5(7H)-one and Lawesson's reagent in refluxing toluene. Pink blocks were grown by slow evaporation from petroleum ether. The resulting crystal structure resides in the orthorhombic space group Pbca with Z = 8 and Z′ = 1. The structure is comprised of a network of C—H...S and C—H...π interactions. No π–π interactions between ring moieties were observed, most likely due to the lack of molecular planarity.

Die Kristallstrukturen der Komplexe von 2,6-Dimethyl-γ-Pyron mit BF3, CuCl2 und HgCl2

Abstract The crystal structures of the complexes of 2,6-dimethyl-4H-pyran-4-one (DMP) with BF3, CuCl2 and HgCl2 have been investigated. In all three case, the site of coordination is to the carbonyl (exocyclic) oxygen atom. DMP·BF3 (I) crystallizes with the monoclinic space group C2/c and the lattice parameters a = 1023.98(5), b = 1465.74(7), c = 1169.03(6) pm, β = 101.347(2)°. In this molecular structure the non-connected molecules are arranged in layers, which spread out parallel to the ab plane. Starting from planar BF3, this molecule is converted by coordination to a tetrahedral entity −OBF3. DMP·CuCl2 (II) belongs to the orthorhombic space group Pnma with a = 1952.43(9), b = 670.84(3), c = 1362.30(6) pm and two different Cu2+ cations. All atoms except the Cl− anions and two atoms of the −CH3 groups reside in mirror planes. The coordination around both Cu2+ cations is square pyramidal −OCuCl4 with the oxygen atom at the apex. The bases are planar and connected via trans-oriented edges to form a strand, running parallel to the b axis. DMP·HgCl2 (III) crystallizes with the space group P21/n and the lattice parameters a = 767.59(4), b = 1970.32(9), c = 1374.41(6) pm, β = 98.257(2)°. Its monoclinic structure is a distorted version of the orthorhombic copper(II) complex structure. The reason is the preference of Hg2+ for the short linear arrangement Cl−Hg−Cl. It is demonstrated, that the crystal structure of DMP·HgCl2 belongs to a translationsgleiche subgroup of the DMP·CuCl2 structure.

Insights into the structural symmetry of YCrO3 from synchrotron X-ray diffraction

A high-resolution synchrotron X-ray diffraction study of a single-crystal YCrO3 compound was employed to obtain its crystallographic information, such as lattice parameters, atomic positions, bond lengths and angles, and local crystalline distortion size and mode. The measurements were taken at 120 K (below the antiferromagnetic transition temperature T N ≃ 141.5 K), 300 K (between T N and the ferroelectric transition temperature T C ≃ 473 K) and 500 K (above T C). Using the high intensity of synchrotron X-rays, it was possible to refine collected patterns with the previously proposed noncentrosymmetric monoclinic structural model (P1211, No. 4) and determine detailed structural parameters. Meanwhile, for a controlled study, the data were refined with the centrosymmetric orthorhombic space group (Pmnb, No. 62). The lattice constants a, b and c and the unit-cell volume increased nearly linearly upon heating. With the P1211 space group, the distributions of bond lengths and angles, as well as local distortion strengths, were observed to be more dispersed. This implies that (i) the local distortion mode of Cr2O6 at 120 K correlates with the formation of canted antiferromagnetic order by Cr1–Cr2 spin interactions, primarily via intermediate O3 and O4 ions; and (ii) the previously reported dielectric anomaly may have a microscopic origin in the strain-balanced Cr1—O3(O4) and Cr2—O5(O6) bonds as well as the local distortion modes of Cr1O6 and Cr2O6 octahedra at 300 K. Local crystalline distortion is shown to be an important factor in the formation of ferroelectric order. The comprehensive set of crystallographic information reported here allows for a complete understanding of the unique magnetic and ferroelectric properties of YCrO3.

Chelated calcium 1D coordination polymer: Crystal growth, characterization and Z scan studies

Calcium acetamido iminodiacetate single crystals with third order nonlinear optical activity have been synthesized by silica gel diffusion method. The structure of the compound was confirmed by elemental analysis, FT – IR, FT-Raman spectroscopy and single crystal X-ray diffraction method. Thermogravimetry was used quite strategically to establish the thermal stability. The compound belongs to orthorhombic space group Pbac, having cell parameters a = 9.4805(6) Å, b = 9.9256 (7) Å, c = 20. 4046 (14) Å, α = β = γ = 90° Optical parameters for the crystals were examined using UV–Visible spectroscopy. Z scan technique has been utilized to find out nonlinear refractive index, nonlinear absorption coefficient and third order susceptibility. Procured results of Z scan support the suitability of the grown crystal for photonics and laser assisted uses.

Structures of Three Alkaline-Earth Metal Germanides Refined from Single-Crystal X-ray Diffraction Data

The calcium- and strontium- alumo-germanides SrxCa1–xAl2Ge2 (x ≈ 0.4) and SrAl2Ge2 have been synthesized and structurally characterized. Additionally, a binary calcium germanide CaGe has also been identified as a byproduct. All three crystal structures have been established from single-crystal X-ray diffraction methods and refined with high accuracy and precision. The binary CaGe crystallizes with a CrB-type structure in the orthorhombic space group Cmcm (no. 63; Z = 4; Pearson symbol oC8), where the germanium atoms are interconnected into infinite zigzag chains, formally [Ge]2−. The calcium atoms are arranged in monocapped trigonal prisms, centered by Ge atoms. SrxCa1−xAl2Ge2 (x ≈ 0.4) and SrAl2Ge2 have been confirmed to crystallize with a CaAl2Si2-type structure in the trigonal space group P3¯m1 (no. 164; Z = 1; Pearson symbol hP5), where the germanium and aluminum atoms form puckered double-layers, formally [Al2Ge2]2−. The calcium atoms are located between the layers and reside inside distorted octahedra of Ge atoms. All presented structures have a valence electron count satisfying the octet rules (e.g., Ca2+Ge2− and Ca2+[Al2Ge2]2−) and can be regarded as Zintl phases.