  This paper investigates small-scale structures of dense gas and dust around
the low-mass protostellar binary NGC1333-IRAS2 using millimeter-wavelength
aperture-synthesis observations from the OVRO and BIMA interferometers. The
detected 3 mm continuum emission is consistent with models of the envelope
around IRAS2A, based on previously reported submillimeter continuum images,
down to the 3", or 500 AU, resolution of the interferometer data. Our data
constrain the contribution of an unresolved point source to 22 mJy. Within the
accuracy of the parameters describing the envelope model, the point source flux
has an uncertainty by up to 25%. We interpret this point source as a cold disk
of mass \gtrsim 0.3 M_\odot. The same envelope model also reproduces
aperture-synthesis line observations of the optically thin isotopic species
C34S and H13CO+. The more optically thick main isotope lines show a variety of
components in the protostellar environment: N2H+ is closely correlated with
dust concentrations as seen at submillimeter wavelengths and is particularly
strong toward the starless core IRAS2C. We hypothesize that N2H+ is destroyed
through reactions with CO that is released from icy grains near the
protostellar sources IRAS2A and B. CS, HCO+, and HCN have complex line shapes
apparently affected by both outflow and infall. In addition to the east-west
jet from IRAS2A, a north-south velocity gradient near this source indicates a
second, perpendicular outflow. This suggests the presence of a binary companion
within 0.3" (65 AU) from IRAS2A as driving source of this outflow. Alternative
explanations of the velocity gradient such as rotation in a circumstellar
envelope or a single, wide-angle outflow are less likely.
