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A rare-earth-containing compound, ytterbium aluminium antimonide, Yb3AlSb3(Ca3AlAs3-type structure), has been successfully synthesized within the Yb–Al–Sb system through flux methods. According to the Zintl formalism, this structure is nominally made up of (Yb2+)3[(Al1−)(1b– Sb2−)2(2b– Sb1−)], where1band2bindicate 1-bonded and 2-bonded, respectively, and Al is treated as part of the covalent anionic network. The crystal structure features infinite corner-sharing AlSb4tetrahedra, [AlSb2Sb2/2]6−, with Yb2+cations residing between the tetrahedra to provide charge balance. Herein, the synthetic conditions, the crystal structure determined from single-crystal X-ray diffraction data, and electronic structure calculations are reported.

The structure, magnetic properties, and 151Eu and 119Sn Mossbauer spectra of the solid-solution Eu11–xSrxZn4Sn2As12 are presented. A new commensurately modulated structure is described for Eu11Zn4S...

Here we report the synthesis and characterization of three quaternary complex chalcogenides, Ag0.72Bi5.48Cu0.88S9 (I), Ag0.70Bi5.30Cu1.3S9 (II), Ag0.34Bi4.54Cu1.98PbS9 (III). All the compounds in this homologous series crystallize in the C2/m space group and can be described as Pavonite structures. This structure type consists of alternating NaCl-like layers with varied thickness (nP), separated by a pair of square pyramids. All the compounds reported here are synthetic analogues of the n = 4 pavonite family and are known as makovickyite minerals. Compounds I–III possess complex crystal structures, consisting of mixed occupancies of Bi/Ag/Pb sites, as well as partially occupied Cu sites. These intrinsic assets lead to ultra-low lattice thermal conductivities, in the range of 0.75–0.42 Wm−1 K−1 from 300–500 K, and make these materials promising candidates for thermoelectric applications. All three structures exhibit very narrow indirect band gaps of less than 0.5 eV as confirmed by DRS measurements. Charge transport properties are consistent with n-type semiconducting behavior with moderate electrical conductivities and large Seebeck coefficients. Low temperature electrical resistivity and Seebeck coefficient measurements are also performed on II. A promising figure of merit, zT, of 0.09 for I and II, 0.11 for III can be achieved at 475 K.

The mineral Zlatogorite, CuNiSb2, was synthesized in the laboratory for the first time by annealing elements at ambient pressure (CuNiSb2-AP). Rietveld refinement of synchrotron powder X-ray diffraction data indicates that CuNiSb2-AP crystallizes in the NiAs-derived structure (P3m1, #164) with Cu and Ni ordering. The structure consists of alternate NiSb6 and CuSb6 octahedral layers via face-sharing. The formation of such structure instead of metal disordered NiAs-type structure (P63/mmc, #194) is validated by the lower energy of the ordered phase by first-principle calculations. Interatomic crystal orbital Hamilton population, electron localization function, and charge density analysis reveal strong Ni-Sb, Cu-Sb, and Cu-Ni bonding and long weak Sb-Sb interactions in CuNiSb2-AP. The magnetic measurement indicates that CuNiSb2-AP is Pauli paramagnetic. First-principle calculations and experimental electrical resistivity measurements reveal that CuNiSb2-AP is a metal. The low Seebeck coefficient and large thermal conductivity suggest that CuNiSb2 is not a potential thermoelectric material. Single crystals were grown by chemical vapor transport. The high pressure sample (CuNiSb2-8 GPa) was prepared by pressing CuNiSb2-AP at 700 °C and 8 GPa. However, the structures of single crystal and CuNiSb2-8 GPa are best fit with a disordered metal structure in the P3m1 space group, corroborated by transmission electron microscopy.

Multimetallic clusters can be described as building blocks in intermetallics, compounds prepared from all metals and/or semi-metals, and in Zintl phases, a subset of intermetallics containing metals with large differences in electronegativity. In many cases, these intermetallic and Zintl phases provide the first clue for the possibilities of bond formation between metals and semi-metals. Recent advances in multimetallic clusters found in Zintl phases and nanoparticles focusing on Ge with transition metals and semi-metals is presented. Colloidal routes to Ge nanocrystals provide an opportunity for kinetically stabilized Ge-metal and Ge-semi-metal bonding. These routes provide crystalline nanoclusters of Ge, hereafter referred to as nanocrystals, that can be structurally characterized. Compositions of Ge nanocrystals containing transition metals, and the semi-metals, Sb, Bi, and Sn, whose structures have recently been elucidated through EXAFS, will be presented along with potential applications.

${\mathrm{Yb}}_{14}\mathrm{Mn}{\mathrm{Sb}}_{11}$ is a magnetic Zintl compound as well as being one of the best high temperature $p$-type thermoelectric materials. According to the Zintl formalism, which defines intermetallic phases where cations and anions are valence satisfied, this structure type is nominally made up of 14 ${\mathrm{Yb}}^{2+}$, 1 ${\mathrm{MnSb}}_{4}^{9\ensuremath{-}}$, 1 ${\mathrm{Sb}}_{3}^{7\ensuremath{-}}$, and 4 ${\mathrm{Sb}}^{3\ensuremath{-}}$ atoms. When Mn is replaced by Mg or Zn, the Zintl defined motifs become 13 ${\mathrm{Yb}}^{2+}$, 1 ${\mathrm{Yb}}^{3+}$, 1 (Mg, Zn)${\mathrm{Sb}}_{4}^{10\ensuremath{-}}$, 1 ${\mathrm{Sb}}_{3}^{7\ensuremath{-}}$, and 4 ${\mathrm{Sb}}^{3\ensuremath{-}}$. The predicted existence of ${\mathrm{Yb}}^{3+}$ based on simple electron counting rules of the Zintl formalism calls the Yb valence of these compounds into question. X-ray absorption near-edge structure, magnetic susceptibility, and specific heat measurements on single crystals of the three analogs show signatures of intermediate valence Yb behavior and in particular, reveal the heavy fermion nature of ${\mathrm{Yb}}_{14}{\mathrm{MgSb}}_{11}$. In these isostructural compounds, Yb can exhibit a variety of electronic configurations from intermediate ($M=\mathrm{Zn}$), mostly 2+ ($M=\mathrm{Mn}$), to 3+ ($M=\mathrm{Mg}$). In all cases, there is a small amount of intermediate valency at the lowest temperatures. The amount of intermediate valency is constant for $M=\mathrm{Mn}$, Mg and temperature dependent for $M=\mathrm{Zn}$. The evolution of the Yb valence correlated to the transport properties of these phases is highlighted. The presence of Yb in this structure type allows for fine tuning of the carrier concentration and thereby the possibility of optimized thermoelectric properties along with unique magnetic phenomena.

We report the synthesis, structure, and magnetic properties of a new Zintl phase and structure type, Eu11Zn4Sn2As12. The structure and composition of this phase have been established by single-crystal X-ray diffraction and electron microprobe analysis. Eu11Zn4Sn2As12 crystallizes in monoclinic space group C2/c (No. 15) with the following lattice parameters: a = 7.5679(4) A, b = 13.0883(6) A, c = 31.305(2) A, and β = 94.8444(7)° [R1 = 0.0398; wR2 = 0.0633 (all data)]. The anisotropic structural features staggered ethane-like [Sn2As6]12– units and infinite ∞2[Zn2As3]5– sheets extended in the a–b plane. Eu cations fill the space between these anionic motifs. Temperature-dependent magnetic properties and magnetoresistance of this Zintl phase have been studied, and the electronic structure and chemical bonding were elucidated using first-principles quantum chemical calculations (TB-LMTO-ASA). Quantum chemical calculations show that the ethane-like units can be considered as consisting of covalent single bonds;...

Large crystals of Yb14MgSb11 were grown through a Sn flux method. Magnetic susceptibility measurements yield an effective magnetic moment of 3.4(1) μB, revealing the presence of both divalent and trivalent Yb in Yb14MgSb11. Previously assumed to only contain Yb2+ as in Yb14MnSb11, the mixed valency demonstrates that Yb14MgSb11 is a Zintl phase.

Eu11–xYbxCd6Sb12 Zintl solid solutions have been prepared by tin flux reaction by employing the elements Eu/Yb/Cd/Sb/Sn in the ratio 11 – xp:xp:6:12:30, where xp is an integer less than 11 representing the preparative amount of Eu (11 – xp) and Yb (xp). Efforts to make the Yb compositions for x exceeding ∼3 resulted in structures other than the Sr11Cd6Sb12 structure type. The crystal structures and compositions were determined by single-crystal and powder X-ray diffraction and wavelength-dispersive X-ray analysis measurements. The title solid-solution Zintl compounds crystallize in the centrosymmetric monoclinic space group C2/m (no. 12, Z = 2) as the Sr11Cd6Sb12 structure type (Pearson symbol mC58), and the lattice parameters decrease with increasing ytterbium content. Single crystal X-ray diffraction shows that Yb atoms are not randomly distributed in the Eu sites but have a site preference which can be attributed to size effects. The influence of the rare earth (RE) metal sites on thermal and electroni...

EuGa4 hosts a magnetic Eu2+ sublattice surrounded by a network of covalently-bound Ga atoms with the BaAl4 structure type (space group I4/ m m m ). In this study, we present the synthesis and characterization of three new single crystal substitutional series Eu A x 1 − x Ga4 with A ​= ​Ca, Sr, or La. X-ray diffraction and resistivity measurements show that Ca substitution induced a structural phase transition from the tetragonal crystal structure at high temperatures to the monoclinic crystal structure (CaGa4 type, space group C2/m) at low temperatures and suppressed the antiferromagnetic ordering temperature to 8.8 ​K for x ​= ​0.45. Comparatively, La or Sr substitution maintained the tetragonal crystal structure and suppressed the antiferromagnetic ordering temperatures to 6.7 ​K and 1.6 ​K for (A, x) = (La, 0.37) and (Sr, 0.91), respectively. In addition to suppressing the magnetic order, magnetization and specific heat measurements indicate the onset of anisotropic metamagnetic transitions in (La, 0.18), (La, 0.37), and (Sr, 0.63), along with an incommensurate-to-commensurate magnetic transition in (Sr, 0.38). By comparing these effects of doping EuGa4, we show how size, disorder, and charge determine the structure-physical property relations in EuGa4.

A novel Zintl phase structure type, Eu7Cd4Sb8-xAsx (x = 2, 3, 4, and 5), with the general formula Eu7Cd4Pn8 (Pn = mixed occupancy Sb and As), was synthesized by molten tin flux reaction. Its structure was determined using single-crystal X-ray diffraction methods. This structure type is only preserved for 2 ≤ x ≤ 5 under our experimental conditions, and efforts to synthesize samples with x2 or x5 resulted in other structure types. The mixed occupancy Sb and As can be thought of as a pseudoatom whose ideal size, in this range of Sb/As ratios, fits the structure. The title phase crystallizes in the I-centered monoclinic space group I2/m (No. 12, Z = 4) with unit cell parameters ranging as follows: a = 19.7116(17)-19.4546(13) Å, b = 4.6751(4)-4.6149(3) Å, c = 24.157(2)-23.871(15) Å, and β = 95.8798(1)-96.016(5)°, depending on the Sb/As ratio. The structure can be described as parallel double pentagonal tubes resulting from Cd-Pn and Pn-Pn bonding. These double pentagons are formed through corner sharing of the Cd-centered CdPn4 tetrahedra and a Pn-Pn interaction from two adjacent CdPn4 tetrahedra. This structure type is closely related to the Sr11Cd6Sb12 structure type as both share the same bonding features of Pn-Pn bonding and double pentagonal tubes. Electron microprobe analysis confirms the composition of these new Zintl solid solution phases. The As exhibits preferential substitution on specific sites, and site specificity trends are supported by lowest energy models from theoretical calculations. Theoretical calculations also predict that Sb-rich compounds should be metallic or semimetallic and that they should become more insulating as As content increases. Members of the solid-solution order ferromagnetically between 5 and 6 K and exhibit relatively low electrical resistivity between 50 and 300 K, ranging from ∼0.57 to ∼26 mΩ·cm, increasing with increasing As content.

Solid-solution Zintl compounds with the formula Eu11Cd6–xZnxSb12 have been synthesized from the elements as single crystals using a tin flux according to the stoichiometry Eu:Cd:Zn:Sb:Sn of 11:6–xp:xp:12:30 with xp = 0, 1, 2, 3, 4, 5, and 6, where xp is the preparative amount of Zn employed in the reaction. The crystal structures and the compositions were established by single-crystal as well as powder X-ray diffraction and wavelength-dispersive X-ray analysis measurements. The title solid-solution Zintl compounds crystallize isostructurally in the centrosymmetric monoclinic space group C 2/m (No. 12, Z = 2) as the Sr11Cd6Sb12 structure type (Pearson symbol mC58). There is a miscibility gap at 3 ≤ xp ≤ 4 where the major product crystallizes in a disordered structure related to the Ca9Mn4Bi9 structure type; otherwise, for all other compositions, the Sr11Cd6Sb12 structure is the majority phase. Eu11Cd6Sb12 shows lower lattice thermal conductivity relative to Eu11Zn6Sb12 consistent with its higher mean atomi...

Magnesium-containing Zintl phase compounds Yb14MgSb11 and Ca14MgSb11 have been prepared by annealing the mixture of the elements at 1075–1275 K. These compounds are isostructural with the Zintl compound Ca14AlSb11 and crystallize in the tetragonal space group I41/acd (Z = 8). Single-crystal X-ray data (90 K) were refined for Yb14MgSb11 [a = 16.625(9) A, c = 22.24(2) A, V = 6145(8) A3, and R1/wR2 (0.0194/0.0398)] and Ca14MgSb11 [a = 16.693(2) A, c = 22.577(5) A, V = 6291(2) A3, R1/wR2 (0.0394/0.0907)]. This structure type has been shown to be highly versatile with a large number of phases with the general formula A14MPn11 (A = Ca, Sr, Ba, Yb, Eu; M = Mn, Zn, Nb, Cd, Group 13 elements; Pn = Group 15 elements). The two compounds reported in this paper are the first Mg-containing analogs. Replacing M with Mg, which is divalent with no d-orbitals, probes electronic structure and properties of this structure type. Mg2+ is well-known to prefer tetrahedral geometry and allows for integration of the properties of ...

The synthesis, crystal structure, magnetic properties, and europium Mossbauer spectroscopy of the new members of the 9–4–9 Zintl family of Eu9Cd4–xCM2+x–y□ySb9 (CM = coinage metal: Au, Ag, and Cu) are reported. These compounds crystallize in the Ca9Mn4Bi9 structure type (9–4–9) with the 4g interstitial site almost half-occupied by coinage metals; these are the first members in the 9–4–9 family where the interstitial positions are occupied by a monovalent metal. All previously known compounds with this structure type include divalent interstitials where these interstitials are typically the same as the transition metals in the anionic framework. Single-crystal magnetic susceptibility data indicate paramagnetic behavior for all three compounds with antiferromagnetic ordering below 10 K (at 100 Oe) that shifts to lower temperature (

Applications of Ge nanocrystals (NCs) are limited by the stability and air reactivity of the Ge surface. In order to promote stability and increase the diversity of ligand functionalization of Ge NCs, the preparation of thiol-passivated Ge NCs via a ligand exchange process was investigated. Herein a successful replacement of oleylamine ligands on the surface of Ge NCs with dodecanethiol is reported. The successful ligand exchange was monitored by FTIR and NMR spectroscopy and it was found that dodecanethiol provided a better surface coverage, leading to stable Ge NC dispersions. Dodecanethiol capping also enabled band gap determination of the NCs by surface photovoltage (SPV) spectroscopy. The SPV measurements indicated an efficient charge separation in the ligand-exchanged Ge NCs. On the other hand, oleylamine-terminated Ge NCs of similar sizes exhibited a very small photovoltage, indicating a poorly passivated surface.

The compounds, Yb14−xTmxMnSb11 (0

Zintl phases are compounds that have shown promise for thermoelectric applications. The title solid–solution Zintl compounds were prepared from the elements as single crystals using a tin flux for compositions x = 0, 1, 2, and 3. Eu_(11)Cd_6Sb_(12–x)As_x (x < 3) crystallize isostructurally in the centrosymmetric monoclinic space group C2/m (no. 12, Z = 2) as the Sr_(11)Cd_6Sb_(12) structure type (Pearson symbol mC58). Efforts to make the As compositions for x exceeding ~3 resulted in structures other than the Sr_(11)Cd_6Sb_(12) structure type. Single-crystal X-ray diffraction indicates that As does not randomly substitute for Sb in the structure but is site specific for each composition. The amount of As determined by structural refinement was verified by electron microprobe analysis. Electronic structures and energies calculated for various model structures of Eu_(11)Cd_6Sb_(10)As_2 (x = 2) indicated that the preferred As substitution pattern involves a mixture of three of the six pnicogen sites in the asymmetric unit. In addition, As substitution at the Pn4 site opens an energy gap at the Fermi level, whereas substitution at the other five pnicogen sites remains semimetallic with a pseudo gap. Thermoelectric properties of these compounds were measured on hot-pressed, fully densified pellets. Samples show exceptionally low lattice thermal conductivities from room temperature to 775 K: 0.78–0.49 W/mK for x = 0; 0.72–0.53 W/mK for x = 1; and 0.70–0.56 W/mK for x = 2. Eu_(11)Cd_6Sb_(12) shows a high p-type Seebeck coefficient (from +118 to 153 μ V/K) but also high electrical resistivity (6.8 to 12.8 mΩ·cm). The value of zT reaches 0.23 at 774 K. The properties of Eu_(11)Cd_6Sb_(12–x)As_x are interpreted in discussion with the As site substitution.

Single crystals of Ce3Ni25.75Ru3.16Al4.1B10 were obtained from a process in which a polycrystalline sample of CeRu2Al2B was annealed in an excess of a Ni–In flux. The initial phase, CeRu2Al2B, does not recrystallize, instead, crystals of a new phase, Ce3Ni25.75Ru3.16Al4.1B10, could be isolated once the flux was removed. The title compound crystallizes in the tetragonal space group P4/nmm (No. 129) with a=1139.02(8), c=801.68(6) pm (c/a=0.70) in the Nd3Ni29Si4B10 structure type. Electrical resistivity measurements reveal metallic behavior with a minimum of 700 µΩ cm and a small residual resistivity ratio of RRR=1.4 indicating a large amount of disorder scattering. The cerium atoms are either in the 4+ or an intermediate valence state with a valence fluctuation temperature far above room temperature.

Earth abundant element clathrate phases are of interest for a number of applications ranging from photovoltaics to thermoelectrics. Silicon-containing type I clathrate is a framework structure with the stoichiometry A8-xSi46 (A = guest atom such as alkali metal) that can be tuned by alloying and doping with other elements. The type I clathrate framework can be described as being composed of two types of polyhedral cages made up of tetrahedrally coordinated Si: pentagonal dodecahedra with 20 atoms and tetrakaidecahedra with 24 atoms in the ratio of 2:6. The cation sites, A, are found in the center of each polyhedral cage. This review focuses on the newest discoveries in the group 13-silicon type I clathrate family: A8E8Si38 (A = alkali metal; E = Al, Ga) and their properties. Possible approaches to new phases based on earth abundant elements and their potential applications will be discussed.

Samples with the type-I clathrate composition Ba{sub 8}Ni{sub x}Si{sub 46-x} have been synthesized and their structure and thermoelectric properties characterized. Microprobe analysis indicates the Ni incorporation to be 2.62{

Single crystals of CeRu0.5Ni0.5Al can be obtained from a Ce-Ni melt using elements as starting materials. The presented compound crystallizes in the orthorhombic space group Pnma (no. 62) with a = 700.38(7), b = 416.92(4) and c = 1562.84(16) pm in the LaNiAl structure type. The compound shows an unusual temperature dependence of the magnetic susceptibility for T < 20 K although the cerium cations exhibit no local moment behavior. This feature is also visible in the electrical resistivity.

CaFe4As3 is a new intermetallic structure type that can be described as a framework comprising of FeAs4 tetrahedra. The structure has similarities to the 1-2-2 superconducting phase in that the Fe/As network is related to the ThCr2Si2 structure. In addition, this phase shows magnetic transitions associated with spin density waves. This phase was prepared from a Sn flux, and it has recently been reported that further expansion of this structure type via chemical substitution is limited. We have developed a solid-state synthesis route for the preparation of CaFe4As3 that involves reacting a stoichiometric combination of the constituent elements. The thermal stability of this material was investigated over the 298–1473 K temperature range. An initial investigation of the Sn grown CaFe4As3 crystals showed that residual Sn that was present on the surface of the crystals reacted with the crystals at temperatures above 1173 K to form new phases. A thermal stability study of Sn-free CaFe4As3 indicated that it decomposed to give CaFe2As2 and Fe2As. The thermal behavior of CaFe2As2 was also investigated and the data showed that it can also form CaFe4As3 at high temperatures. The solid-state synthesis route presented herein and additional solid solution studies may provide opportunities for the prepartion of materials with this structure type with improved electronic properties.

Phase stability of the type-I clathrate compound Ba_(8)Al_(x)Si_(46−x) and the thermoelectric property dependence on chemical composition are presented. Polycrystalline samples were prepared by argon arc melting and annealing. Results of powder X-ray diffraction and electron microprobe analysis show that the type-I structure is formed without framework deficiency for 8≤x≤15. Lattice constant a increases linearly with the increase of x. Thermoelectric properties were measured for x=12, 14 and 15. The Seebeck coefficients are negative, with the absolute values increasing with x. The highest figure of merit zT=0.24 was observed for x=15 at T=1000 K, with carrier electron density n=3×10^(21) cm^(−3). A theoretical calculation based on the single parabolic band model reveals the optimum carrier concentration to be n~4×10^(20) cm^(−3), where zT~0.7 at T=1000K is predicted.

Na4Si4 is a Zintl salt composed of Na+ cations and Si 4 4 − tetrahedral anions and is a unique solid-state precursor to clathrate structures and nanomaterials. In order to provide opportunities for the synthesis of complex materials, phosphorus was explored as a possible substituent for silicon. Phosphorus doped sodium silicides Na4Si4−xPx (x≤0.04) were prepared by reaction of Na with the mechanically alloyed Si4−x:Px (x=0.04, 0.08, 0.12) mixture in a sealed Nb tube at 650 °C for 3 days. Energy dispersive X-ray spectroscopy confirms the presence of P in all products. Powder X-ray diffraction patterns are consistent with the retention of the Na4Si4 crystal structure. As the amount of P increases, a new peak in the diffraction pattern that can be assigned to black phosphorus is apparent above the background. Raman and solid-state NMR provide information on phosphorus substitution in the Na4Si4 structure. Raman spectroscopy shows a shift of the most intense band assigned to the Si 4 4 − ν1 (A1) mode from 486.4 to 484.0 cm−1 with increasing P, consistent with P replacement of Si. Differential nuclear spin-lattice relaxation for the Si sites determined via 29Si solid-state NMR provides direct evidence for Si–P bonding in the (Si1−xPx)4− tetrahedron. The 23Na NMR shows additional Na…P interactions and the 31P NMR shows two P sites, consistent with P presence in both of the crystallographic sites in the (Si4)4− tetrahedron.

A hydrogen-containing inorganic clathrate with the nominal composition, K(7)(H(2))(3)Si(46), has been prepared in 98% yield by the reaction of K(4)Si(4) with NH(4)Br. Rietveld refinement of the powder X-ray diffraction data is consistent with the clathrate type I structure. Elemental analysis and (1)H MAS NMR confirmed the presence of hydrogen in this material. Type I clathrate structure is built up from a Si framework with two types of cages where the guest species, in this case K and H(2), can reside: a large cage composed of 24 Si, in which the guest resides in the 6d position, and a smaller one composed of 20 Si, in which the guest occupies the 2a position (cubic space group Pm3n). Potassium occupancy was examined using spherical aberration (Cs) corrected scanning transmission electron microscopy (STEM). The high-angle annular dark-field (HAADF) STEM experimental and simulated images indicated that the K is deficient in both the 2a and the 6d sites. (1)H and (29)Si MAS NMR are consistent with the presence of H(2) in a restricted environment and the clathrate I structure, respectively. FTIR and (29)Si{(1)H} CP MAS NMR results show no evidence for a Si-H bond, suggesting that hydrogen is present as H(2) in interstitial sites. Thermal gravimetry (TG) mass spectrometry (MS) provide additional confirmation of H(2) with hydrogen loss at approximately 400 degrees C.

Single crystals of the new Zintl phases AIn2P2 [A = Ca (calcium indium phosphide), Sr (strontium indium phosphide) and Ba (barium indium phosphide)] have been synthesized from a reactive indium flux. CaIn2P2 and SrIn2P2 are isostructural with EuIn2P2 and crystallize in the space group P63/mmc. The alkaline earth cations A are located at a site with 3m symmetry; In and P are located at sites with 3m symmetry. The structure type consists of layers of A2+ cations separated by [In2P2]2- anions that contain [In2P6] eclipsed ethane-like units that are further connected by shared P atoms. This yields a double layer of six-membered rings in which the In-In bonds are parallel to the c axis and to one another. BaIn2P2 crystallizes in a new structure type in the space group P2(1)/m with Z = 4, with all atoms residing on sites of mirror symmetry. The structure contains layers of Ba2+ cations separated by [In2P2]2- layers of staggered [In2P6] units that form a mixture of four-, five- and six-membered rings. As a consequence of this more complicated layered structure, both the steric and electronic requirements of the large Ba2+ cation are met.

Single crystals of EuGa2Pn2 (Pn = P, As) were grown from a molten Ga flux and characterized by single-crystal X-ray diffraction at 100(1) K. They are isostructural and crystallize in a new structure type (monoclinic, P2/m, a = 9.2822(9) A, b = 3.8967(4) A, c = 12.0777(11) A, β = 95.5220(10)°, R1 = 0.0148, wR2 = 0.0325 (EuGa2P2) and a = 9.4953(7) A, b = 4.0294(3) A, c = 12.4237(9) A, β = 95.3040(10)°, R1 = 0.0155, wR2 = 0.0315 (EuGa2As2)). The structures consist of alternating layers of two-dimensional Ga2Pn2 anions and Eu cations. The anion layers are composed of Ga2Pn6 staggered, ethane-like moieties having a rare Ga−Ga bonding motif; these moieties are connected in a complex fashion by means of shared Pn atoms. Both structures show small residual electron densities that can be modeled by adding a Eu atom and removing two bonded Ga atoms, resulting in structures (

Large, high quality single crystals of a new Zintl phase, EuIn(2)As(2), have been synthesized from a reactive indium flux. EuIn(2)As(2) is isostructural to the recently reported phase EuIn(2)P(2), and it is only the second reported member of the group of compounds with formula AM(2)X(2) (A = alkali, alkaline earth, or rare earth cation; M = transition or post-transition metal; and X = Group 14 or 15 element) that crystallizes in the hexagonal space group P6(3)/mmc (a = 4.2067(3) A, c = 17.889(2) A and Z = 2). The structure type contains layers of A(2+) cations separated by [M(2)X(2)](2-) layers along the crystallographic c-axis. Crystals of the title compound were mounted for magnetic measurements, with the crystallographic c-axis oriented either parallel or perpendicular to the direction of the applied field. The collective magnetization versus temperature and field data indicate two magnetic exchange interactions near 16 K, one involving Eu(2+)...Eu(2+) intralayer coupling and the other involving Eu(2+)...Eu(2+) coupling between layers. EuIn(2)As(2) is metallic and magnetoresistive, as is the isostructural phosphide, and both compounds have coincident resistivity and magnetic ordering transitions, consistent with the observation of colossal magnetoresistance. Negative colossal magnetoresistance (MR = {[rho(H) - rho(0)]/rho(H)} x 100%) of up to -143% (at T = 17.5 K, H = 5 T) is observed for EuIn(2)As(2), approximately half of that observed for the more resistive phosphide, which has a higher magnetic ordering temperature and local moment coupling strength.

High purity NaGe was directly prepared by a low-temperature reaction of NaH and Ge. The product was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy. This material is a useful starting reagent for the preparation of Ge nanoparticles. Hydrogen-terminated germanium (Ge) nanoparticles were prepared by reaction of NaGe with NH4Br. These Ge nanoparticles could be prepared as amorphous or crystalline nanoparticles in quantitative yields and with a narrow size distribution. The nanoparticles were functionalized via thermally initiated hydrogermylation with 1-eicosyne, CH3(CH2)17C≡CH to produce alkyl-terminated Ge nanoparticles. The modified Ge nanoparticles were characterized by powder XRD, transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and Raman spectroscopy, and photoluminescence (PL) spectroscopy. The alkyl-functionalized Ge nanoparticles can be expected to have promising applications in many technological and biological areas.

A hydrogen-encapsulated inorganic clathrate, which is stable at ambient temperature and pressure, has been prepared in high yield. Na5.5(H2)2.15Si46 is a sodium-deficient, hydrogen-encapsulated, type I silicon clathrate. It was prepared by the reaction between NaSi and NH4Br under dynamic vacuum at 300 degrees C. The Rietveld refinement of the powder X-ray diffraction data is consistent with the clathrate type I structure. The type I clathrate structure has two types of cages where the guest species, in this case Na and H2, can reside: a large cage composed of 24 Si, in which the guest resides in the 6d crystallographic position, and a smaller one composed of 20 Si, in which the guest occupies the 2a position. Solid-state 23Na, 1H, and 29Si MAS NMR confirmed the presence of both sodium and hydrogen in the clathrate cages. 23Na NMR shows that sodium completely fills the small cage and is deficient in the larger cage. The 1H NMR spectrum shows a pattern consistent with mobile hydrogen in the large cage. 29Si NMR spectrum is consistent with phase pure type I clathrate framework. Elemental analysis is consistent with the stoichiometry Na5.5(H2.15)2Si46. The sodium occupancy was also examined using spherical aberration (Cs) corrected scanning transmission electron microscopy (STEM). The high-angle annular dark-field (HAADF) STEM experimental and simulated images indicated that the Na occupancy of the large cage, 6d sites, is less than 2/3, consistent with the NMR and elemental analysis.

Various reaction conditions, such as reductant, time, procedure, concentration, and temperature, were investigated with the aim of finding a simple, optimized synthetic route for the synthesis of crystalline germanium nanoparticles. Results from these studies indicate that sodium naphthalide is an ideal reductant and that the reaction is virtually complete within 10 min. Furthermore, it was observed that a two-pot synthesis resulted in a cleaner, narrower distribution of nanoparticle size and that the narrowest size distribution (∼20%) was produced when a dilute Na(naphth) in glyme mixture was utilized. The optimum initial reduction temperature was found to be 0 °C. It was also shown that concentration and temperature play an important role in controlling nanoparticle size. The best reaction conditions, as stated above, produced nanoparticles with a size dispersion of ∼20% when combined. Transmission electron microscopy (TEM), selected-area electron diffraction (SAED), high-resolution TEM (HRTEM), energy-...

Single crystals of a new Zintl compound, EuIn2P2, were grown from indium metal as a flux solvent. The compound crystallizes in the hexagonal P6(3)/mmc space group with a unit cell of a = 4.0829(6) A, c = 17.595(4) A, and Z = 2. It contains alternating Eu2+ layers and [In2P2]2- layers. This compound is paramagnetic at high temperatures with a magnetic transition at 24 K. In the magnetically ordered state, it shows large magnetic anisotropy. The temperature-dependent resistivity of this compound suggests interaction between conduction electrons and local spins. Negative colossal magnetoresistance of up to −398% (MR = {[ρ(H) − ρ(0)]/ρ(H)} × 100%) at 5 T is observed at 24 K.

Butyl-capped crystalline germanium (Ge) nanoparticles were synthesized at room temperature in dimethoxyethane by reduction of GeCl4 with Na(naphthalide) and subsequent reaction with butyl Grignard. The nanoparticles were isolated in hexane and characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDX), elemental analysis, and X-ray powder diffraction (XRD). The product from this room-temperature reaction was heated under vacuum at temperatures of 200−600 °C at 50 °C intervals. The product obtained from the 300 °C treatment was soluble in hexane, while the products from temperatures greater than 300 °C were not. SAED was consistent with crystalline Ge from the initial synthesis at room temperature and amorphous Ge for the product heated under vacuum to 300 °C. X-ray powder diffraction of the 300 °C product shows the transition from amorphous to crystalline nanoparticles occurring between 550 and 600 °C. TEM shows that the n...

The compound Ca14MnP11 crystallizes in the Ca14AlSb11 structure type with the tetragonal space group I 4 1 / acd ( Z = 8 ) and lattice parameters of a = 15.3255 ( 7 ) A , c = 20.7565 ( 9 ) at 90 K. The structure consists of MnP49− tetrahedron, P37− trimer, 4 P3− isolated anions and 14 Ca2+ cations. Similar to other compounds of this structure type containing phosphorous, the P37− trimer has a central P atom that is best modeled in the structure as being equally split between two sites. In addition, there is no additional distortion of the manganese-containing tetrahedron compared with the main group analog, Ca14GaP11, suggesting that the Mn oxidation state is Mn2+. Temperature-dependent magnetic susceptibility shows that the compound is paramagnetic over the entire temperature range measured (2–300 K). The data can be fit with a modified Curie–Weiss law and provide an effective magnetic moment of 5.80 (2) B.M. with a Weiss constant of −2.13(2) K and χ 0 = - 9 ( 1 ) × 1 - 5 emu / mol . This moment is significantly higher than those measured for any of the Mn-containing analogs and is consistent with Mn2+. This result will be discussed in light of the electron counting scheme for Mn compounds of the Ca14AlSb11 structure-type.

A new rare-earth rich Zintl phase Yb11GaSb9 was synthesized by direct fusion of the corresponding elements, and large single crystals of the compound were obtained from high temperature flux synthesis. Its crystal structure was determined by single-crystal X-ray diffraction to be orthorhombic in the non-centrosymmetric space group Iba2 (No. 45), Z = 4 ( R 1 = 3.24 % , w R 2 = 6.40 % ) with a = 11.7257 ( 12 ) A , b = 12.3204 ( 13 ) A , c = 16.633 ( 2 ) A measured at 90(3) K. The structure belongs to the Ca11InSb9-type and can be viewed as built of isolated Sb4-tetrahedra centered by Ga, Sb-dimers and isolated Sb anions, which are separated by Yb2+ cations. Electron count according to the Zintl formalism suggests that the phase is electron-precise and charge-balanced, which is supported by the virtually temperature-independent magnetization for Yb11GaSb9. Electrical resistivity data from 2 to 400 K confirm that Yb11GaSb9 is a small band-gap semiconductor with room temperature resistivity ρ 298 = 45.1 m Ω cm , and low-temperature resistivity at 2 K ρ 2 = 1.9 Ω cm . As such, Yb11GaSb9 and related compounds might be promising materials for thermoelectric applications, and currently, efforts to synthesize new members of this family and test their thermoelectric performance are under way.

The europium-151 Mossbauer spectra of the Eu(14)MnP(11), Eu(14)MnAs(11), and Eu(14)MnSb(11) Zintl compounds, measured between 4.2 and 100 K, reveal europium(II) for all four crystallographically inequivalent europium sites in Eu(14)MnAs(11) and Eu(14)MnSb(11) and europium(II) and europium(III) for the three 32g and the 16f europium sites in Eu(14)MnP(11), respectively. Below the ordering temperatures of 52, 74, and 92 K, only very small hyperfine fields of 2-4 T are observed at the europium sites as a result of the polarization by the manganese magnetic moments. At 4.2 K, the europium(II) magnetic moments are ordered, and hyperfine fields of 24.4, 24.8, and 19.3 T are observed in Eu(14)MnP(11), Eu(14)MnAs(11), and Eu(14)MnSb(11), respectively, fields that are typical for magnetically ordered europium(II) ions. At 4.2 K the 16f europium(III) sites in Eu(14)MnP(11) experience a transferred hyperfine field of 33 T from the neighboring ordered europium(II) moments. Between its Curie temperature and 4.2 K, the europium-151 Mossbauer spectra of Eu(14)MnSb(11) reveal that the europium(II) moments order below ca. 13 K, i.e., below the second magnetic transition observed in magnetic measurements. Between their Curie temperatures and 4.2 K, the europium-151 Mossbauer spectra of Eu(14)MnP(11) and Eu(14)MnAs(11) are complex and have been analyzed with two models, models that give equivalently good fits. However, the second model in which the spectra are fit with a three-dimensional relaxation of the europium(II) and europium(III) hyperfine fields is preferred for its physical meaning and its reduced number of fitted parameters.

A new transition metal Zintl phase, Yb(9)Zn(4+x)Sb(9), was prepared by high-temperature flux syntheses as large single crystals, or by direct fusion of the corresponding elements in polycrystalline form. Its crystal structure was determined by single-crystal X-ray diffraction. Its Ca-counterpart, hitherto known as Ca(9)Zn(4)Sb(9), and the presence of nonstoichiometry in it were also studied. Yb(9)Zn(4+x)Sb(9) was found to exist in a narrow homogeneity range, as suggested from the crystallographic data at 90(3) K (orthorhombic, space group Pbam (No. 55), Z = 2): (1) a = 21.677(2) A, b = 12.3223(10) A, c = 4.5259(4) A, R1 = 3.09%, wR2 = 7.18% for Yb(9)Zn(4.23(2))Sb(9); (2) a = 21.706(2) A, b = 12.3381(13) A, c = 4.5297(5) A, R1 = 2.98%, wR2 = 5.63% for Yb(9)Zn(4.380(12))Sb(9); and (3) a = 21.700(2) A, b = 12.3400(9) A, c = 4.5339(4) A, R1 = 2.75%, wR2 = 5.65% for Yb(9)Zn(4.384(14))Sb(9). The isostructural Ca(9)Zn(4.478(8))Sb(9) has unit cell parameters a = 21.830(2) A, b = 12.4476(9) A, and c = 4.5414(3) A (R1 = 3.33%, wR2 = 5.83%). The structure type in which these compounds crystallize is related to the Ca(9)Mn(4)Bi(9) type, and can be considered an interstitially stabilized variant. Formal electron count suggests that the Yb or Ca cations are in the +2 oxidation state. This is supported by the virtually temperature-independent magnetization for Yb(9)Zn(4.5)Sb(9). Electrical resistivity data show that Yb(9)Zn(4.5)Sb(9) and Ca(9)Zn(4.5)Sb(9) are poor metals with room-temperature resistivity of 10.2 and 19.6 mOmega.cm, respectively.

Single crystals of Na2Ti2Sb2O have been grown by NaSb flux method. It crystallizes in platelet morphology with dark silver color. The growth conditions are optimized and crystal structure has been analyzed by single crystal X-ray diffraction at 88.7, 120.0 and 150.0 K. The structure analysis result shows that there is a non-linear change in temperature-dependent lattice parameters suggesting that previously reported anomaly in temperature-dependent magnetization and electrical resistivity of polycrystalline samples around 120 K is associated with the structure distortion. Temperature-dependent magnetic susceptibility of a single crystal sample grown by NaSb flux method also exhibits a sharp transition around 120 K confirming that this anomaly is intrinsic to Na2Ti2Sb2O.

The solid solution of the ternary transition metal Zintl phase Ca 14-x Eu x MnSb 11 (0 < x < 14) has been prepared by heating a mixture of stoichiometric amounts of the elements in a two-zone furnace with T high = 1100 °C and T low = 1050 °C. The ternary transition metal compounds crystallize in the tetragonal space group I4 1 /acd and are isostructural with the Zintl compound Ca 14 AlSb 11 . The lattice parameters of the Ca 14-x Eu x MnSb 11 compounds linearly increase with increasing Eu substitution for Ca. The Eu atoms preferentially occupy the C a (2) site first and subsequently occupy Ca(4), Ca(1), and Ca(3), in order, among the four crystallographically inequivalent Ca sites. Temperature-dependent magnetic susceptibility measurements of the solid solution reveal that Eu replacement for Ca induces complex magnetic interactions in the compound, from simple ferromagnetic interactions for Ca 14 -MnSb 11 to ferrimagnetic interactions for Eu 14 MnSb 11 , because of the Eu 2+ (4f 7 ) magnetic moment. The paramagnetic Curie temperature of the Ca 14-x Eu x MnSb 11 compounds shows an interesting change with varying x, and the magnetic easy axis gradually changes in the solid solution from perpendicular (for Ca 14 MnSb 11 ) to parallel (for Eu 14 MnSb 11 ) to the crystal c axis. The electrical transport properties of the Ca 14-x Eu x MnSb 11 (x = 0, 3, 11) compounds show a close relation to their magnetic properties and are compared to the previous results for Ca 14-x Eu x MnSb 11 (x = 13, 14). The influence of Eu doping on the structural and physical property of Ca 14-x Eu x MnSb 11 is discussed in terms of the site preferences of Eu for the four different Ca sites.

The compounds Ca14AlP11, Ca14MnP11, and Eu14MnP11 have been synthesized and are isostructural to the Zintl compound, Ca14AlSb11. Eu14MnP11 is a ferromagnet showing colossal magnetoresistance at TC = 52 K, Ca14MnP11 shows paramagnetic behavior down to 5 K, and Ca14AlP11 is nonmagnetic. The formula unit for these Zintl compounds is A14MPn11 and comprises 14 A cations, a MPn4 tetrahedron, four isolated Pn anions, and a Pn3 linear unit. The central Pn of the Pn3 unit is believed to be positionally disordered, and it has been speculated that the disorder is static rather than dynamic. To address this issue, 31P solid-state NMR was applied to these new compounds to provide insight into the magnetic ordering and structural changes. The NMR chemical shift anisotropy and the dipolar coupling for the 31P nuclei as well as the quadrupolar coupling for the 27Al nucleus in the diamagnetic compound Ca14AlP11 provide structural details consistent with the Zintl structure. Wide-line 31P NMR and EPR were applied to the pa...

In the course of our investigation aimed at the preparation of anisotropic cluster materials using a combination of oxide and chloride ligands to induce directional bonding preferences in the cluster unit, a series of niobium oxychloride cluster compounds AxNb6Cl12O2 (A=K, x=0.72(2); A=Rb, x=0.736(7); A=Cs, x=0.938(4); A=In, x=0.634(8)) was obtained by solid state synthesis. The cluster framework is based on (Nb6Cl10iO2i)Cl4aO2a clusters connected via oxide ligands in the a → direction with two Nb–O linkages between adjacent clusters, which resembles intercluster bonding in Chevrel–Sergent phases, while in the other two directions, the linkages occur through single Cla–a bridges. The framework generates channels where the cations A+ are located. The electronic band structure of the series features a narrow partially occupied band originating from a Nb–Nb bonding state. Magnetic and ESR measurements show the presence of localized unpaired electrons, and resistivity measurements indicate a semiconducting behavior.

The effect of four different dopants (Ca, Sr, Ba, and Yb) on the structural and physical properties of the ternary rare-earth transition metal compound, Eu14MnSb11, has been investigated. The compounds, Eu14-xAxMnSb11 (A = Ca, Sr, Ba, and Yb, x = 1), have been prepared by heating the mixture of stoichiometric amounts of the elements, sealed in a quartz jacketed Ta tube, in a two-zone furnace with Thigh = 1100 °C and Tlow = 1050 °C for 10 days. These compounds are isostructural with the Zintl compound Ca14AlSb11 and crystallize in the tetragonal space group I41/acd, Z = 8. The lattice parameters of the doped compound increase correspondingly as the radius of the metal dopant (A2+) increases. The preference of the dopants onto the four crystallographically inequivalent sites of Eu was examined by single-crystal X-ray diffraction. The magnetization of the compounds has been measured as a function of temperature and applied magnetic field. Temperature-dependent magnetic susceptibility measurement of powder sa...

Large single crystals of EuMn2P2 were grown from a tin flux whose melt composition and reaction temperature profile were optimized to avoid impurity phases. The crystal structure of EuMn2P2 is of the CaAl2Si2 structure type. The structure was determined by single-crystal X-ray crystallography, with the unit cell in the trigonal lattice, a=4.1294(3) A and c=6.9936(8) A, at T=90 K (Z=1, R1=0.0239, wR2=0.0632) and belongs to the P 3 m1 (#164) space group. Temperature-dependent magnetic susceptibility, resistivity, and neutron diffraction measurements on single crystals indicate that EuMn2P2 is an antiferromagnetic insulator with a Neel temperature of 16.5±0.25 K. The Eu spins order in a simple magnetic structure where the spins in the a–b plane are aligned ferromagnetically; these ferromagnetic planes are stacked antiferromagnetically along the c-axis.

Single crystals of Ce3(Ni/Al/Ga)11 were obtained from an Al flux reaction. Single crystals of the title compound crystallizing in the orthorhombic space group Immm (No. 71, Z = 2) with a = 436.38(14), b = 1004.5(3) and c = 1293.4(4) pm. This is a standardized unit cell of the previously published La3Al11 structure type. Wavelength dispersive microprobe provides the composition of Ce3.11(1)Ni0.03(1)Al8.95(1)Ga1.90(1). Single crystal refinement provides the composition Ce3Ni0.08Al9.13Ga1.78 with substitution of the Ni and Ga on the Al1 and Al4 sites with the Al2 and Al3 solely occupied by Al. Magnetic susceptibility measurements reveal antiferromagnetic ordering with TN = 4.8 K and there is no evidence for a ferromagnetic ordering that has been reported for Ce3Al11. The effective magnetic moment was found to be μeff = 1.9μB/Ce, which is lower than the expected value for trivalent Ce (2.54μB/Ce).

The new compounds Eu14MnAs11 and Eu14MnP11 were synthesized from stoichiometric amounts of the elements. The compounds are isotypic to Ca14AlSb11 and crystallize in the tetragonal space group I41/acd (Z = 8). Lattice parameters obtained from single-crystal X-ray diffraction at 130 K are a = 16.318 (2) A, c = 21.684 (4) A and a = 15.930 (4) A, c = 21.213 (5) A for Eu14MnAs11 and Eu14MnP11, respectively. In the refinement of each structure, the central Pn(4) site of a Pn37- linear unit (Pn = As, P) shows positional disorder; this is in contrast to the ordered structures formed when Pn = Sb and Bi. Eu14MnAs11 and Eu14MnP11 are ferromagnetic with transitions at 74 and 52 K, respectively. Eu14MnAs11 also has a low-temperature transition at ∼25 K. Resistivity measurements indicate an insulator-to-metal transition near the magnetic transition, and plots of ln ρ vs 1/T are linear above TC, providing activation energies of 0.03 eV (As; 240−300 K) and 0.31 eV (P). The resistivity is suppressed in the presence of a ...

The new pnictide oxide Sr2MnZn2As2O2 is reported. The crystal structure of this compound consists of a 1:1 intergrowth of square-planar MnO22- layers and ThCr2Si2-type Zn2As22- layers interspersed by Sr cations. This compound has been prepared by sintering the stoichiometric ratio of SrO, Mn, Zn, and As in a fused-silica ampule under 0.2 atm of Ar at 1000 °C for 1 week. The sample quality has been examined by Rietveld refinement of the powder X-ray diffraction data, and the transition metal site (2a and 4d) selectivity has been analyzed by Rietveld refinement of powder neutron diffraction data. Furthermore, effects of this structural order on the magnetic susceptibility and interaction between the magnetic layers have been analyzed by temperature-dependent magnetization measurements. The magnetic structures of both phases, A2MnZn2As2O2 (A = Sr, Ba), have been investigated by temperature-dependent powder neutron diffraction. The Ba analogue exhibits two-dimensional short-range order below about 40 K, where...

The new pseudo-binary intermetallic compound, Ti 11 (Sb,Sn) 8 , has been synthesized by reacting Ti and Sb in a Sn flux at 1100°C and its structure determined from both single-crystal X-ray and neutron diffraction data (orthorhombic, Pnma , Z=4, X-ray diffraction at 90 K: a =14.6877(6) A, b =5.5677(2) A, c =17.7207(7) A, V =1449.14(10) A 3 , neutron diffraction at room temperature: a =14.677(6) A, b =5.577(3) A, c =17.716 (6) A, V =1450(1) A 3 ). The structure contains two differently oriented repeating layers and interstitial atoms that are closely connected to make linear chains aligned along the crystal b axis. The compound exhibits mixed site occupancies of Sb and Sn on the anion sites. The phase width (Sb/Sn ratio=0.98–1.40) was determined by microprobe elemental analysis. The electrical resistivity of a single crystal as a function of temperature is anisotropic ( ρ //b =1∼2×10 −1 mΩ·cm, ρ ⊥b =0.5×10 −1 mΩ·cm) and confirms that this compound is metallic. Magnetic susceptibility measurements show Pauli paramagnetism.

The synthesis of silicon nanoclusters and their characterization by multinuclear solid-state nuclear magnetic resonance (NMR) is presented. A combination of 23Na, 29Si, and 13C magic angle spinning with and without cross polarization to 1H nuclei have been used to investigate the reaction of sodium silicide (NaSi) with silicon tetrachloride (SiCl4) followed by varying degrees of surface passivation. The 23Na and 29Si NMR spectra of NaSi distinguish the two crystallographically inequivalent sites for each, consistent with the crystal structure. This compound exhibits extreme diamagnetic chemical shifts for 29Si of −361 and −366 ppm. NaSi is reacted with SiCl4 in refluxing ethylene glycol dimethyl ether to produce both amorphous and crystalline Si nanoparticles with surfaces capped by chlorine. This reaction produces new 29Si resonances that survive subsequent capping and oxidation reactions. The 29Si NMR spectrum shows that the product is incompletely passivated with butyl groups and gives several peaks ly...